"声明一个boolean公共变量，表明当前httpconnection是否得到服务器回应。
你的连接线程中在连接之前置这个变量为false；
另起一个监视线程，拿到那个HttpConnection的连接对象，并循环监视这个boolean公共变量。如果指定时间内(20秒后)你的boolean公共变量还是false，那么就主动置httpconnection=null。这样，那边连接线程就会抛出异常退出来。"??-----zhengyun
写了Timer类来实现.(学习国外一个网站上的写法)
class?Timer?extends?Thread?{
??
??protected?int?m_rate?=?100;
??
??private?int?m_length;
??
??private?int?m_elapsed;
??
??public?Timer(int?length)?{
???//?Assign?to?member?variable
???m_length?=?length;
???//?Set?time?elapsed
???m_elapsed?=?0;
??}
??
??public?synchronized?void?reset()?{
???m_elapsed?=?0;
???System.out.println("reset?timer");
??}
??
??public?synchronized?void?setTimeOut()
??{
???m_elapsed?=?m_length+1;
??}
??
??public?void?run()?{
???//?循环
???System.out.println("timer?running");
???for?(;;)?{
????//?Put?the?timer?to?sleep
????try?{
?????Thread.sleep(m_rate);
????}?catch?(InterruptedException?ioe)?{
?????continue;
????}
????synchronized?(this)?{
?????//?Increment?time?remaining
??m_elapsed?+=?m_rate;
?????//?Check?to?see?if?the?time?has?been?exceeded
?????if?(m_elapsed?>?m_length?&&?!isConnActive)?{?//isConnActive?为全局变量
??????//?Trigger?a?timeout
??????timeout();
??????break;
?????}
????}
???}
??}
??
??public?void?timeout()?{
??????httpConnection?=?null;
??????System.out.println("conn?time?>?"?+?TIME_OUT?+?"?ms");
????}
?}
?
在http连接线程调用的同是调用?new?Timer(20*1000).start();
需要重新计时时候调用timer.reset();