被監聽的線程類:
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package cn.std.test;
import java.util.Observable;
import cn.std.util.DateUtil;
public class RunThread extends Observableimplements Runnable{
// 此方法一經調用,立馬可以通知觀察者,在本例中是監聽線程
publicvoid doBusiness(){
if ( true ){
super .setChanged();
}
notifyObservers();
}
@Override
publicvoid run() {
intc = 0 ;
while ( true ){ //模擬線程運行一段時間之後退出
System.out.println( "Runing- " +c+ " " +DateUtil.getStdDateTime());
try {
Thread.sleep( 2000 );
} catch (InterruptedException e) {
e.printStackTrace();
doBusiness();
break ;
}
c++;
//模擬拋出異常
try {
if (c== 4 ){
Stringstr = null ;
str.length(); //此處將會拋出空指針異常
}
} catch (Exception e) {
e.printStackTrace();
doBusiness(); //在拋出異常時調用,通知觀察者,讓其重啓線程
break ; //異常拋出之後,一定要跳出循環,保證將線程送進地獄
}
}
}
publicstatic void main(String[] args) {
RunThreadrun = new RunThread();
Listener listen = new Listener();
un.addObserver(listen);
newThread(run).start();
//run.doBusiness();
}
} |
被監聽的線程需要繼承Observable類,繼承之後輕鬆變身爲被觀察者doBusiness方法,此處可以加上你的業務處理內容,接下來是Listener
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package cn.std.test;
import java.util.Observable;
import java.util.Observer;
public class Listener implements Observer{
@Override
publicvoid update(Observable o, Object arg) {
System.out.println( "RunThread死機" );
RunThreadrun = new RunThread();
run.addObserver( this );
newThread(run).start();
System.out.println( "RunThread重啓" );
}
} |
很簡單,只要實現Observer接口,實現其update方法,在方法內部重啓線程