Java知多少（65）线程的挂起、恢复和终止
11个月前 (05-17)
有时，线程的挂起是很有用的。例如，一个独立的线程可以用来显示当日的时间。如果用户不希望用时钟，线程被挂起。在任何情形下，挂起线程是很简单的，一旦挂起，重新启动线程也是一件简单的事。
挂起，终止和恢复线程机制在Java 2和早期版本中有所不同。尽管你运用Java 2的途径编写代码，你仍需了解这些操作在早期Java环境下是如何完成的。例如，你也许需要更新或维护老的代码。你也需要了解为什么Java 2会有这样的变化。因为这些原因，下面内容描述了执行线程控制的原始方法，接着是Java 2的方法。
Java 1.1或更早版本的线程的挂起、恢复和终止
先于Java2的版本，程序用Thread 定义的suspend() 和 resume() 来暂停和再启动线程。它们的形式如下：
final void suspend( )
final void resume( )
下面的程序描述了这些方法：
&span class="lit"&1&/span& &span class="com"&//&/span&&span class="com"& Using suspend() and resume().&/span&
&span class="lit"&2&/span& &span class="kwd"&class&/span& &span class="typ"&NewThread&/span& &span class="kwd"&implements&/span& &span class="typ"&Runnable&/span& &span class="pun"&{&/span&
&span class="lit"&3&/span&
&span class="typ"&String&/span&&span class="pln"& name&/span&&span class="pun"&;&/span& &span class="com"&//&/span&&span class="com"& name of thread&/span&
&span class="lit"&4&/span&
&span class="typ"&Thread&/span&&span class="pln"& t&/span&&span class="pun"&;&/span&
&span class="lit"&5&/span&
&span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& threadname&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&6&/span&&span class="pln"&
name &/span&&span class="pun"&=&/span&&span class="pln"& threadname&/span&&span class="pun"&;&/span&
&span class="lit"&7&/span&&span class="pln"&
t &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&Thread&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&,&/span&&span class="pln"& name&/span&&span class="pun"&);&/span&
&span class="lit"&8&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"New thread: "&/span& &span class="pun"&+&/span&&span class="pln"& t&/span&&span class="pun"&);&/span&
&span class="lit"&9&/span&&span class="pln"&
t&/span&&span class="pun"&.&/span&&span class="pln"&start&/span&&span class="pun"&();&/span& &span class="com"&//&/span&&span class="com"& Start the thread&/span&
&span class="lit"&10&/span&
&span class="pun"&}&/span&
&span class="lit"&11&/span&
&span class="com"&//&/span&&span class="com"& This is the entry point for thread.&/span&
&span class="lit"&12&/span&
&span class="kwd"&public&/span& &span class="kwd"&void&/span&&span class="pln"& run&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&
&span class="lit"&13&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&14&/span&
&span class="kwd"&for&/span&&span class="pun"&(&/span&&span class="kwd"&int&/span&&span class="pln"& i &/span&&span class="pun"&=&/span& &span class="lit"&15&/span&&span class="pun"&;&/span&&span class="pln"& i &/span&&span class="pun"&&&/span& &span class="lit"&0&/span&&span class="pun"&;&/span&&span class="pln"& i&/span&&span class="pun"&--&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&15&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&": "&/span& &span class="pun"&+&/span&&span class="pln"& i&/span&&span class="pun"&);&/span&
&span class="lit"&16&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&200&/span&&span class="pun"&);&/span&
&span class="lit"&17&/span&
&span class="pun"&}&/span&
&span class="lit"&18&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&19&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" interrupted."&/span&&span class="pun"&);&/span&
&span class="lit"&20&/span&
&span class="pun"&}&/span&
&span class="lit"&21&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" exiting."&/span&&span class="pun"&);&/span&
&span class="lit"&22&/span&
&span class="pun"&}&/span&
&span class="lit"&23&/span& &span class="pun"&}&/span&
&span class="lit"&24&/span& &span class="kwd"&class&/span& &span class="typ"&SuspendResume&/span& &span class="pun"&{&/span&
&span class="lit"&25&/span&
&span class="kwd"&public&/span& &span class="kwd"&static&/span& &span class="kwd"&void&/span&&span class="pln"& main&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& args&/span&&span class="pun"&[])&/span& &span class="pun"&{&/span&
&span class="lit"&26&/span&
&span class="typ"&NewThread&/span&&span class="pln"& ob1 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"One"&/span&&span class="pun"&);&/span&
&span class="lit"&27&/span&
&span class="typ"&NewThread&/span&&span class="pln"& ob2 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"Two"&/span&&span class="pun"&);&/span&
&span class="lit"&28&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&29&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&30&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&suspend&/span&&span class="pun"&();&/span&
&span class="lit"&31&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread One"&/span&&span class="pun"&);&/span&
&span class="lit"&32&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&33&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&resume&/span&&span class="pun"&();&/span&
&span class="lit"&34&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread One"&/span&&span class="pun"&);&/span&
&span class="lit"&35&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&suspend&/span&&span class="pun"&();&/span&
&span class="lit"&36&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread Two"&/span&&span class="pun"&);&/span&
&span class="lit"&37&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&38&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&resume&/span&&span class="pun"&();&/span&
&span class="lit"&39&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread Two"&/span&&span class="pun"&);&/span&
&span class="lit"&40&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&41&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&
&span class="lit"&42&/span&
&span class="pun"&}&/span&
&span class="lit"&43&/span&
&span class="com"&//&/span&&span class="com"& wait for threads to finish&/span&
&span class="lit"&44&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&45&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Waiting for threads to finish."&/span&&span class="pun"&);&/span&
&span class="lit"&46&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&
&span class="lit"&47&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&
&span class="lit"&48&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&49&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&
&span class="lit"&50&/span&
&span class="pun"&}&/span&
&span class="lit"&51&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread exiting."&/span&&span class="pun"&);&/span&
&span class="lit"&52&/span&
&span class="pun"&}&/span&
&span class="lit"&53&/span& &span class="pun"&}&/span&
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253
&span class="lit"&1&/span& &span class="com"&//&/span&&span class="com"& Using suspend() and resume().&/span& &span class="lit"&2&/span& &span class="kwd"&class&/span& &span class="typ"&NewThread&/span& &span class="kwd"&implements&/span& &span class="typ"&Runnable&/span& &span class="pun"&{&/span& &span class="lit"&3&/span&&&&& &span class="typ"&String&/span&&span class="pln"& name&/span&&span class="pun"&;&/span& &span class="com"&//&/span&&span class="com"& name of thread&/span& &span class="lit"&4&/span&&&&& &span class="typ"&Thread&/span&&span class="pln"& t&/span&&span class="pun"&;&/span& &span class="lit"&5&/span&&&&& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& threadname&/span&&span class="pun"&)&/span& &span class="pun"&{&/span& &span class="lit"&6&/span&&span class="pln"&&&&&&&&& name &/span&&span class="pun"&=&/span&&span class="pln"& threadname&/span&&span class="pun"&;&/span& &span class="lit"&7&/span&&span class="pln"&&&&&&&&& t &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&Thread&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&,&/span&&span class="pln"& name&/span&&span class="pun"&);&/span& &span class="lit"&8&/span&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"New thread: "&/span& &span class="pun"&+&/span&&span class="pln"& t&/span&&span class="pun"&);&/span& &span class="lit"&9&/span&&span class="pln"&&&&&&&&& t&/span&&span class="pun"&.&/span&&span class="pln"&start&/span&&span class="pun"&();&/span& &span class="com"&//&/span&&span class="com"& Start the thread&/span&&span class="lit"&10&/span&&&&& &span class="pun"&}&/span&&span class="lit"&11&/span&&&&& &span class="com"&//&/span&&span class="com"& This is the entry point for thread.&/span&&span class="lit"&12&/span&&&&& &span class="kwd"&public&/span& &span class="kwd"&void&/span&&span class="pln"& run&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&&span class="lit"&13&/span&&&&&&&&& &span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&14&/span&&&&&&&&&&&&& &span class="kwd"&for&/span&&span class="pun"&(&/span&&span class="kwd"&int&/span&&span class="pln"& i &/span&&span class="pun"&=&/span& &span class="lit"&15&/span&&span class="pun"&;&/span&&span class="pln"& i &/span&&span class="pun"&>&/span& &span class="lit"&0&/span&&span class="pun"&;&/span&&span class="pln"& i&/span&&span class="pun"&--&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&15&/span&&&&&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&": "&/span& &span class="pun"&+&/span&&span class="pln"& i&/span&&span class="pun"&);&/span&&span class="lit"&16&/span&&&&&&&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&200&/span&&span class="pun"&);&/span&&span class="lit"&17&/span&&&&&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&18&/span&&&&&&&&& &span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&19&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" interrupted."&/span&&span class="pun"&);&/span&&span class="lit"&20&/span&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&21&/span&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" exiting."&/span&&span class="pun"&);&/span&&span class="lit"&22&/span&&&&& &span class="pun"&}&/span&&span class="lit"&23&/span& &span class="pun"&}&/span&&span class="lit"&24&/span& &span class="kwd"&class&/span& &span class="typ"&SuspendResume&/span& &span class="pun"&{&/span&&span class="lit"&25&/span&&&&& &span class="kwd"&public&/span& &span class="kwd"&static&/span& &span class="kwd"&void&/span&&span class="pln"& main&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& args&/span&&span class="pun"&[])&/span& &span class="pun"&{&/span&&span class="lit"&26&/span&&&&&&&&& &span class="typ"&NewThread&/span&&span class="pln"& ob1 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"One"&/span&&span class="pun"&);&/span&&span class="lit"&27&/span&&&&&&&&& &span class="typ"&NewThread&/span&&span class="pln"& ob2 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"Two"&/span&&span class="pun"&);&/span&&span class="lit"&28&/span&&&&&&&&& &span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&29&/span&&&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&30&/span& &span class="pln"&&&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&suspend&/span&&span class="pun"&();&/span&&span class="lit"&31&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread One"&/span&&span class="pun"&);&/span&&span class="lit"&32&/span&&&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&33&/span& &span class="pln"&&&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&resume&/span&&span class="pun"&();&/span&&span class="lit"&34&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread One"&/span&&span class="pun"&);&/span&&span class="lit"&35&/span& &span class="pln"&&&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&suspend&/span&&span class="pun"&();&/span&&span class="lit"&36&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread Two"&/span&&span class="pun"&);&/span&&span class="lit"&37&/span&&&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&38&/span& &span class="pln"&&&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&resume&/span&&span class="pun"&();&/span&&span class="lit"&39&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread Two"&/span&&span class="pun"&);&/span&&span class="lit"&40&/span&&&&&&&&& &span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&41&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&&span class="lit"&42&/span&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&43&/span&&&&&&&&& &span class="com"&//&/span&&span class="com"& wait for threads to finish&/span&&span class="lit"&44&/span&&&&&&&&& &span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&45&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Waiting for threads to finish."&/span&&span class="pun"&);&/span&&span class="lit"&46&/span& &span class="pln"&&&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&&span class="lit"&47&/span& &span class="pln"&&&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&&span class="lit"&48&/span&&&&&&&&& &span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&49&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&&span class="lit"&50&/span&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&51&/span&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread exiting."&/span&&span class="pun"&);&/span&&span class="lit"&52&/span&&&&& &span class="pun"&}&/span&&span class="lit"&53&/span& &span class="pun"&}&/span&
程序的部分输出如下：
&span class="lit"&1&/span& &span class="typ"&New&/span&&span class="pln"& thread&/span&&span class="pun"&:&/span& &span class="typ"&Thread&/span&&span class="pun"&[&/span&&span class="typ"&One&/span&&span class="pun"&,&/span&&span class="lit"&5&/span&&span class="pun"&,&/span&&span class="pln"&main&/span&&span class="pun"&]&/span&
&span class="lit"&2&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&15&/span&
&span class="lit"&3&/span& &span class="typ"&New&/span&&span class="pln"& thread&/span&&span class="pun"&:&/span& &span class="typ"&Thread&/span&&span class="pun"&[&/span&&span class="typ"&Two&/span&&span class="pun"&,&/span&&span class="lit"&5&/span&&span class="pun"&,&/span&&span class="pln"&main&/span&&span class="pun"&]&/span&
&span class="lit"&4&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&15&/span&
&span class="lit"&5&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&14&/span&
&span class="lit"&6&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&14&/span&
&span class="lit"&7&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&13&/span&
&span class="lit"&8&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&13&/span&
&span class="lit"&9&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&12&/span&
&span class="lit"&10&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&12&/span&
&span class="lit"&11&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&11&/span&
&span class="lit"&12&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&11&/span&
&span class="lit"&13&/span& &span class="typ"&Suspending&/span&&span class="pln"& thread &/span&&span class="typ"&One&/span&
&span class="lit"&14&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&10&/span&
&span class="lit"&15&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&9&/span&
&span class="lit"&16&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&8&/span&
&span class="lit"&17&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&7&/span&
&span class="lit"&18&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&6&/span&
&span class="lit"&19&/span& &span class="typ"&Resuming&/span&&span class="pln"& thread &/span&&span class="typ"&One&/span&
&span class="lit"&20&/span& &span class="typ"&Suspending&/span&&span class="pln"& thread &/span&&span class="typ"&Two&/span&
&span class="lit"&21&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&10&/span&
&span class="lit"&22&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&9&/span&
&span class="lit"&23&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&8&/span&
&span class="lit"&24&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&7&/span&
&span class="lit"&25&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&6&/span&
&span class="lit"&26&/span& &span class="typ"&Resuming&/span&&span class="pln"& thread &/span&&span class="typ"&Two&/span&
&span class="lit"&27&/span& &span class="typ"&Waiting&/span& &span class="kwd"&for&/span&&span class="pln"& threads to finish&/span&&span class="pun"&.&/span&
&span class="lit"&28&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&5&/span&
&span class="lit"&29&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&5&/span&
&span class="lit"&30&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&4&/span&
&span class="lit"&31&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&4&/span&
&span class="lit"&32&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&3&/span&
&span class="lit"&33&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&3&/span&
&span class="lit"&34&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&2&/span&
&span class="lit"&35&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&2&/span&
&span class="lit"&36&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&1&/span&
&span class="lit"&37&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&1&/span&
&span class="lit"&38&/span& &span class="typ"&Two&/span&&span class="pln"& exiting&/span&&span class="pun"&.&/span&
&span class="lit"&39&/span& &span class="typ"&One&/span&&span class="pln"& exiting&/span&&span class="pun"&.&/span&
&span class="lit"&40&/span& &span class="typ"&Main&/span&&span class="pln"& thread exiting&/span&&span class="pun"&.&/span&
12345678910111213141516171819202122232425262728293031323334353637383940
&span class="lit"&1&/span& &span class="typ"&New&/span&&span class="pln"& thread&/span&&span class="pun"&:&/span& &span class="typ"&Thread&/span&&span class="pun"&[&/span&&span class="typ"&One&/span&&span class="pun"&,&/span&&span class="lit"&5&/span&&span class="pun"&,&/span&&span class="pln"&main&/span&&span class="pun"&]&/span& &span class="lit"&2&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&15&/span& &span class="lit"&3&/span& &span class="typ"&New&/span&&span class="pln"& thread&/span&&span class="pun"&:&/span& &span class="typ"&Thread&/span&&span class="pun"&[&/span&&span class="typ"&Two&/span&&span class="pun"&,&/span&&span class="lit"&5&/span&&span class="pun"&,&/span&&span class="pln"&main&/span&&span class="pun"&]&/span& &span class="lit"&4&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&15&/span& &span class="lit"&5&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&14&/span& &span class="lit"&6&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&14&/span& &span class="lit"&7&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&13&/span& &span class="lit"&8&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&13&/span& &span class="lit"&9&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&12&/span&&span class="lit"&10&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&12&/span&&span class="lit"&11&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&11&/span&&span class="lit"&12&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&11&/span&&span class="lit"&13&/span& &span class="typ"&Suspending&/span&&span class="pln"& thread &/span&&span class="typ"&One&/span&&span class="lit"&14&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&10&/span&&span class="lit"&15&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&9&/span&&span class="lit"&16&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&8&/span&&span class="lit"&17&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&7&/span&&span class="lit"&18&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&6&/span&&span class="lit"&19&/span& &span class="typ"&Resuming&/span&&span class="pln"& thread &/span&&span class="typ"&One&/span&&span class="lit"&20&/span& &span class="typ"&Suspending&/span&&span class="pln"& thread &/span&&span class="typ"&Two&/span&&span class="lit"&21&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&10&/span&&span class="lit"&22&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&9&/span&&span class="lit"&23&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&8&/span&&span class="lit"&24&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&7&/span&&span class="lit"&25&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&6&/span&&span class="lit"&26&/span& &span class="typ"&Resuming&/span&&span class="pln"& thread &/span&&span class="typ"&Two&/span&&span class="lit"&27&/span& &span class="typ"&Waiting&/span& &span class="kwd"&for&/span&&span class="pln"& threads to finish&/span&&span class="pun"&.&/span&&span class="lit"&28&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&5&/span&&span class="lit"&29&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&5&/span&&span class="lit"&30&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&4&/span&&span class="lit"&31&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&4&/span&&span class="lit"&32&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&3&/span&&span class="lit"&33&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&3&/span&&span class="lit"&34&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&2&/span&&span class="lit"&35&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&2&/span&&span class="lit"&36&/span& &span class="typ"&Two&/span&&span class="pun"&:&/span& &span class="lit"&1&/span&&span class="lit"&37&/span& &span class="typ"&One&/span&&span class="pun"&:&/span& &span class="lit"&1&/span&&span class="lit"&38&/span& &span class="typ"&Two&/span&&span class="pln"& exiting&/span&&span class="pun"&.&/span&&span class="lit"&39&/span& &span class="typ"&One&/span&&span class="pln"& exiting&/span&&span class="pun"&.&/span&&span class="lit"&40&/span& &span class="typ"&Main&/span&&span class="pln"& thread exiting&/span&&span class="pun"&.&/span&
Thread类同样定义了stop() 来终止线程。它的形式如下：
void stop( )
一旦线程被终止，它不能被resume() 恢复继续运行。
Java 2中挂起、恢复和终止线程
Thread定义的suspend()，resume()和stop()方法看起来是管理线程的完美的和方便的方法，它们不能用于新Java版本的程序。下面是其中的原因。Thread类的suspend()方法在Java2中不被赞成，因为suspend()有时会造成严重的系统故障。假定对关键的数据结构的一个线程被锁定的情况，如果该线程在那里挂起，这些锁定的线程并没有放弃对资源的控制。其他的等待这些资源的线程可能死锁。
Resume()方法同样不被赞同。它不引起问题，但不能离开suspend()方法而独立使用。Thread类的stop()方法同样在Java 2中受到反对。这是因为该方法可能导致严重的系统故障。设想一个线程正在写一个精密的重要的数据结构且仅完成一个零头。如果该线程在此刻终止，则数据结构可能会停留在崩溃状态。
因为在Java 2中不能使用suspend()，resume()和stop() 方法来控制线程，你也许会想那就没有办法来停止，恢复和结束线程。其实不然。相反，线程必须被设计以使run() 方法定期检查以来判定线程是否应该被挂起，恢复或终止它自己的执行。有代表性的，这由建立一个指示线程状态的标志变量来完成。只要该标志设为“running”，run()方法必须继续让线程执行。如果标志为“suspend”，线程必须暂停。若设为“stop”，线程必须终止。
当然，编写这样的代码有很多方法，但中心主题对所有的程序应该是相同的。
下面的例题阐述了从Object继承的wait()和notify()方法怎样控制线程的执行。该例与前面讲过的程序很像。然而，不被赞同的方法都没有用到。让我们思考程序的执行。
NewTread 类包含了用来控制线程执行的布尔型的实例变量suspendFlag。它被构造函数初始化为false。Run()方法包含一个监测suspendFlag 的同步声明的块。如果变量是true，wait()方法被调用以挂起线程。Mysuspend()方法设置suspendFlag为true。Myresume()方法设置suspendFlag为false并且调用notify()方法来唤起线程。最后，main()方法被修改以调用mysuspend()和myresume()方法。
&span class="lit"&1&/span& &span class="com"&//&/span&&span class="com"& Suspending and resuming a thread for Java2&/span&
&span class="lit"&2&/span& &span class="kwd"&class&/span& &span class="typ"&NewThread&/span& &span class="kwd"&implements&/span& &span class="typ"&Runnable&/span& &span class="pun"&{&/span&
&span class="lit"&3&/span&
&span class="typ"&String&/span&&span class="pln"& name&/span&&span class="pun"&;&/span& &span class="com"&//&/span&&span class="com"& name of thread&/span&
&span class="lit"&4&/span&
&span class="typ"&Thread&/span&&span class="pln"& t&/span&&span class="pun"&;&/span&
&span class="lit"&5&/span&
&span class="kwd"&boolean&/span&&span class="pln"& suspendFlag&/span&&span class="pun"&;&/span&
&span class="lit"&6&/span&
&span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& threadname&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&7&/span&&span class="pln"&
name &/span&&span class="pun"&=&/span&&span class="pln"& threadname&/span&&span class="pun"&;&/span&
&span class="lit"&8&/span&&span class="pln"&
t &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&Thread&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&,&/span&&span class="pln"& name&/span&&span class="pun"&);&/span&
&span class="lit"&9&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"New thread: "&/span& &span class="pun"&+&/span&&span class="pln"& t&/span&&span class="pun"&);&/span&
&span class="lit"&10&/span&&span class="pln"&
suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&false&/span&&span class="pun"&;&/span&
&span class="lit"&11&/span&&span class="pln"&
t&/span&&span class="pun"&.&/span&&span class="pln"&start&/span&&span class="pun"&();&/span& &span class="com"&//&/span&&span class="com"& Start the thread&/span&
&span class="lit"&12&/span&
&span class="pun"&}&/span&
&span class="lit"&13&/span&
&span class="com"&//&/span&&span class="com"& This is the entry point for thread.&/span&
&span class="lit"&14&/span&
&span class="kwd"&public&/span& &span class="kwd"&void&/span&&span class="pln"& run&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&
&span class="lit"&15&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&16&/span&
&span class="kwd"&for&/span&&span class="pun"&(&/span&&span class="kwd"&int&/span&&span class="pln"& i &/span&&span class="pun"&=&/span& &span class="lit"&15&/span&&span class="pun"&;&/span&&span class="pln"& i &/span&&span class="pun"&&&/span& &span class="lit"&0&/span&&span class="pun"&;&/span&&span class="pln"& i&/span&&span class="pun"&--&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&17&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&": "&/span& &span class="pun"&+&/span&&span class="pln"& i&/span&&span class="pun"&);&/span&
&span class="lit"&18&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&200&/span&&span class="pun"&);&/span&
&span class="lit"&19&/span&
&span class="kwd"&synchronized&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&20&/span&
&span class="kwd"&while&/span&&span class="pun"&(&/span&&span class="pln"&suspendFlag&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&21&/span& &span class="pln"&
wait&/span&&span class="pun"&();&/span&
&span class="lit"&22&/span&
&span class="pun"&}&/span&
&span class="lit"&23&/span&
&span class="pun"&}&/span&
&span class="lit"&24&/span&
&span class="pun"&}&/span&
&span class="lit"&25&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&26&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" interrupted."&/span&&span class="pun"&);&/span&
&span class="lit"&27&/span&
&span class="pun"&}&/span&
&span class="lit"&28&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" exiting."&/span&&span class="pun"&);&/span&
&span class="lit"&29&/span&
&span class="pun"&}&/span&
&span class="lit"&30&/span&
&span class="kwd"&void&/span&&span class="pln"& mysuspend&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&
&span class="lit"&31&/span&&span class="pln"&
suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&true&/span&&span class="pun"&;&/span&
&span class="lit"&32&/span&
&span class="pun"&}&/span&
&span class="lit"&33&/span&
&span class="kwd"&synchronized&/span& &span class="kwd"&void&/span&&span class="pln"& myresume&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&
&span class="lit"&34&/span&&span class="pln"&
suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&false&/span&&span class="pun"&;&/span&
&span class="lit"&35&/span& &span class="pln"&
notify&/span&&span class="pun"&();&/span&
&span class="lit"&36&/span&
&span class="pun"&}&/span&
&span class="lit"&37&/span& &span class="pun"&}&/span&
&span class="lit"&38&/span& &span class="kwd"&class&/span& &span class="typ"&SuspendResume&/span& &span class="pun"&{&/span&
&span class="lit"&39&/span&
&span class="kwd"&public&/span& &span class="kwd"&static&/span& &span class="kwd"&void&/span&&span class="pln"& main&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& args&/span&&span class="pun"&[])&/span& &span class="pun"&{&/span&
&span class="lit"&40&/span&
&span class="typ"&NewThread&/span&&span class="pln"& ob1 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"One"&/span&&span class="pun"&);&/span&
&span class="lit"&41&/span&
&span class="typ"&NewThread&/span&&span class="pln"& ob2 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"Two"&/span&&span class="pun"&);&/span&
&span class="lit"&42&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&43&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&44&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&mysuspend&/span&&span class="pun"&();&/span&
&span class="lit"&45&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread One"&/span&&span class="pun"&);&/span&
&span class="lit"&46&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&47&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&myresume&/span&&span class="pun"&();&/span&
&span class="lit"&48&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread One"&/span&&span class="pun"&);&/span&
&span class="lit"&49&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&mysuspend&/span&&span class="pun"&();&/span&
&span class="lit"&50&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread Two"&/span&&span class="pun"&);&/span&
&span class="lit"&51&/span&
&span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&
&span class="lit"&52&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&myresume&/span&&span class="pun"&();&/span&
&span class="lit"&53&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread Two"&/span&&span class="pun"&);&/span&
&span class="lit"&54&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&55&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&
&span class="lit"&56&/span&
&span class="pun"&}&/span&
&span class="lit"&57&/span&
&span class="com"&//&/span&&span class="com"& wait for threads to finish&/span&
&span class="lit"&58&/span&
&span class="kwd"&try&/span& &span class="pun"&{&/span&
&span class="lit"&59&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Waiting for threads to finish."&/span&&span class="pun"&);&/span&
&span class="lit"&60&/span& &span class="pln"&
ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&
&span class="lit"&61&/span& &span class="pln"&
ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&
&span class="lit"&62&/span&
&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&
&span class="lit"&63&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&
&span class="lit"&64&/span&
&span class="pun"&}&/span&
&span class="lit"&65&/span&
&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread exiting."&/span&&span class="pun"&);&/span&
&span class="lit"&66&/span&
&span class="pun"&}&/span&
&span class="lit"&67&/span& &span class="pun"&}&/span&
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667
&span class="lit"&1&/span& &span class="com"&//&/span&&span class="com"& Suspending and resuming a thread for Java2&/span& &span class="lit"&2&/span& &span class="kwd"&class&/span& &span class="typ"&NewThread&/span& &span class="kwd"&implements&/span& &span class="typ"&Runnable&/span& &span class="pun"&{&/span& &span class="lit"&3&/span&&&&& &span class="typ"&String&/span&&span class="pln"& name&/span&&span class="pun"&;&/span& &span class="com"&//&/span&&span class="com"& name of thread&/span& &span class="lit"&4&/span&&&&& &span class="typ"&Thread&/span&&span class="pln"& t&/span&&span class="pun"&;&/span& &span class="lit"&5&/span&&&&& &span class="kwd"&boolean&/span&&span class="pln"& suspendFlag&/span&&span class="pun"&;&/span& &span class="lit"&6&/span&&&&& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& threadname&/span&&span class="pun"&)&/span& &span class="pun"&{&/span& &span class="lit"&7&/span&&span class="pln"&&&&&&&&& name &/span&&span class="pun"&=&/span&&span class="pln"& threadname&/span&&span class="pun"&;&/span& &span class="lit"&8&/span&&span class="pln"&&&&&&&&& t &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&Thread&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&,&/span&&span class="pln"& name&/span&&span class="pun"&);&/span& &span class="lit"&9&/span&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"New thread: "&/span& &span class="pun"&+&/span&&span class="pln"& t&/span&&span class="pun"&);&/span&&span class="lit"&10&/span&&span class="pln"&&&&&&&&& suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&false&/span&&span class="pun"&;&/span&&span class="lit"&11&/span&&span class="pln"&&&&&&&&& t&/span&&span class="pun"&.&/span&&span class="pln"&start&/span&&span class="pun"&();&/span& &span class="com"&//&/span&&span class="com"& Start the thread&/span&&span class="lit"&12&/span&&&&& &span class="pun"&}&/span&&span class="lit"&13&/span&&&&& &span class="com"&//&/span&&span class="com"& This is the entry point for thread.&/span&&span class="lit"&14&/span&&&&& &span class="kwd"&public&/span& &span class="kwd"&void&/span&&span class="pln"& run&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&&span class="lit"&15&/span&&&&&&&&& &span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&16&/span&&&&&&&&&&&&& &span class="kwd"&for&/span&&span class="pun"&(&/span&&span class="kwd"&int&/span&&span class="pln"& i &/span&&span class="pun"&=&/span& &span class="lit"&15&/span&&span class="pun"&;&/span&&span class="pln"& i &/span&&span class="pun"&>&/span& &span class="lit"&0&/span&&span class="pun"&;&/span&&span class="pln"& i&/span&&span class="pun"&--&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&17&/span&&&&&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&": "&/span& &span class="pun"&+&/span&&span class="pln"& i&/span&&span class="pun"&);&/span&&span class="lit"&18&/span&&&&&&&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&200&/span&&span class="pun"&);&/span&&span class="lit"&19&/span&&&&&&&&&&&&&&&&& &span class="kwd"&synchronized&/span&&span class="pun"&(&/span&&span class="kwd"&this&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&20&/span&&&&&&&&&&&&&&&&&&&&& &span class="kwd"&while&/span&&span class="pun"&(&/span&&span class="pln"&suspendFlag&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&21&/span& &span class="pln"&&&&&&&&&&&&&&&&&&&&&&&&&wait&/span&&span class="pun"&();&/span&&span class="lit"&22&/span&&&&&&&&&&&&&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&23&/span&&&&&&&&&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&24&/span&&&&&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&25&/span&&&&&&&&& &span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&26&/span&&&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" interrupted."&/span&&span class="pun"&);&/span&&span class="lit"&27&/span&&&&&&&&& &span class="pun"&}&/span&&span class="lit"&28&/span&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="pln"&name &/span&&span class="pun"&+&/span& &span class="str"&" exiting."&/span&&span class="pun"&);&/span&&span class="lit"&29&/span&&&&& &span class="pun"&}&/span&&span class="lit"&30&/span&&&&& &span class="kwd"&void&/span&&span class="pln"& mysuspend&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&&span class="lit"&31&/span&&span class="pln"&&&&&&&&& suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&true&/span&&span class="pun"&;&/span&&span class="lit"&32&/span&&&&& &span class="pun"&}&/span&&span class="lit"&33&/span&&&&& &span class="kwd"&synchronized&/span& &span class="kwd"&void&/span&&span class="pln"& myresume&/span&&span class="pun"&()&/span& &span class="pun"&{&/span&&span class="lit"&34&/span&&span class="pln"&&&&&&&&& suspendFlag &/span&&span class="pun"&=&/span& &span class="kwd"&false&/span&&span class="pun"&;&/span&&span class="lit"&35&/span& &span class="pln"&&&&&&&&&notify&/span&&span class="pun"&();&/span&&span class="lit"&36&/span&&&&& &span class="pun"&}&/span&&span class="lit"&37&/span& &span class="pun"&}&/span&&span class="lit"&38&/span& &span class="kwd"&class&/span& &span class="typ"&SuspendResume&/span& &span class="pun"&{&/span&&span class="lit"&39&/span&&&&& &span class="kwd"&public&/span& &span class="kwd"&static&/span& &span class="kwd"&void&/span&&span class="pln"& main&/span&&span class="pun"&(&/span&&span class="typ"&String&/span&&span class="pln"& args&/span&&span class="pun"&[])&/span& &span class="pun"&{&/span&&span class="lit"&40&/span&&&&&&&&&&span class="typ"&NewThread&/span&&span class="pln"& ob1 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"One"&/span&&span class="pun"&);&/span&&span class="lit"&41&/span&&&&&&&&&&span class="typ"&NewThread&/span&&span class="pln"& ob2 &/span&&span class="pun"&=&/span& &span class="kwd"&new&/span& &span class="typ"&NewThread&/span&&span class="pun"&(&/span&&span class="str"&"Two"&/span&&span class="pun"&);&/span&&span class="lit"&42&/span&&&&&&&&&&span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&43&/span&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&44&/span& &span class="pln"&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&mysuspend&/span&&span class="pun"&();&/span&&span class="lit"&45&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread One"&/span&&span class="pun"&);&/span&&span class="lit"&46&/span&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&47&/span& &span class="pln"&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&myresume&/span&&span class="pun"&();&/span&&span class="lit"&48&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread One"&/span&&span class="pun"&);&/span&&span class="lit"&49&/span& &span class="pln"&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&mysuspend&/span&&span class="pun"&();&/span&&span class="lit"&50&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Suspending thread Two"&/span&&span class="pun"&);&/span&&span class="lit"&51&/span&&&&&&&&&&& &span class="typ"&Thread&/span&&span class="pun"&.&/span&&span class="pln"&sleep&/span&&span class="pun"&(&/span&&span class="lit"&1000&/span&&span class="pun"&);&/span&&span class="lit"&52&/span& &span class="pln"&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&myresume&/span&&span class="pun"&();&/span&&span class="lit"&53&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Resuming thread Two"&/span&&span class="pun"&);&/span&&span class="lit"&54&/span&&&&&&&&&&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&55&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&&span class="lit"&56&/span&&&&&&&&&&span class="pun"&}&/span&&span class="lit"&57&/span&&&&&&&&&&span class="com"&//&/span&&span class="com"& wait for threads to finish&/span&&span class="lit"&58&/span&&&&&&&&&&span class="kwd"&try&/span& &span class="pun"&{&/span&&span class="lit"&59&/span&&&&&&&&&&& &span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Waiting for threads to finish."&/span&&span class="pun"&);&/span&&span class="lit"&60&/span& &span class="pln"&&&&&&&&&&&ob1&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&&span class="lit"&61&/span& &span class="pln"&&&&&&&&&&&ob2&/span&&span class="pun"&.&/span&&span class="pln"&t&/span&&span class="pun"&.&/span&&span class="pln"&join&/span&&span class="pun"&();&/span&&span class="lit"&62&/span&&&&&&&&&&span class="pun"&}&/span& &span class="kwd"&catch&/span& &span class="pun"&(&/span&&span class="typ"&InterruptedException&/span&&span class="pln"& e&/span&&span class="pun"&)&/span& &span class="pun"&{&/span&&span class="lit"&63&/span&&&&&&&&&&&&&&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread Interrupted"&/span&&span class="pun"&);&/span&&span class="lit"&64&/span&&&&&&&&&&span class="pun"&}&/span&&span class="lit"&65&/span&&&&&&&&&&span class="typ"&System&/span&&span class="pun"&.&/span&&span class="kwd"&out&/span&&span class="pun"&.&/span&&span class="pln"&println&/span&&span class="pun"&(&/span&&span class="str"&"Main thread exiting."&/span&&span class="pun"&);&/span&&span class="lit"&66&/span&&&&& &span class="pun"&}&/span&&span class="lit"&67&/span& &span class="pun"&}&/span&
该程序的输出与前面的程序相同。此书的后面部分，你将看到用Java 2机制控制线程的更多例子。尽管这种机制不像老方法那样“干净”，然而，它是确保运行时不发生错误的方法。它是所有新的代码必须采用的方法。
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