处理定时任务,超时终止方法
实现功能:处理一批任务,如果某个任务的处理时间超过最大处理时间,则终止该任务的执行,继续执行下一个任务
实现思路:三线程实现,处理一个任务时,启动一个任务处理线程处理方案,再启动一个定时器线程检测是否超时,并通过一个同步变量保证任务时串行执行的。实现代码如下:
疑问:
1、在Java中,类似超时任务的处理有没有其它的实现方式?
2、下面几个异常会无规律地出现,想不明白其中的道理,请明白人帮忙解释一下,
2.1、没有执行“Normal Process”,也没有执行“ending ok!” :为什么interrupt后,doSomething里没有捕获到异常? start task!20
ThreadID:27>>> starting!
ThreadID: MonitorThread running!
ThreadID:27>>> stoping end!
end task!20
2.2、没有执行“ending ok!” :stop后,run里后续处理不做了?start task!18
ThreadID:25>>> starting!
ThreadID: MonitorThread running!
ThreadID:25>>> AbNormal Proccess! processTime=18000
ThreadID:25>>> stoping end!
2.3、执行了2次“AbNormal Proccess! ”,但没有执行“ending ok!” :为什么会打印2次?
start task!10
ThreadID:17>>> starting!
ThreadID: MonitorThread running!
ThreadID:17>>> AbNormal Proccess! processTime=10000ThreadID:17>>> AbNormal Proccess! processTime=10000ThreadID:17>>> stoping end!
end task!10
代码如下:
Java code
package MultiThreadTest;
import java.util.Timer;
import java.util.TimerTask;
public class MainThread {
private Object lock = new Object();
public void waitLock() throws InterruptedException {
synchronized (lock) {
lock.wait();
}
}
public void notifyLock() {
synchronized (lock) {
lock.notify();
}
}
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) {
MainThread mainThread = new MainThread();
for (int i = 2; i <= 20; i += 2) {
System.out.println("start task!" + i);
ProccessThread proccessThread = new ProccessThread(mainThread,
i * 1000);
MonitorThread monitorThread = new MonitorThread(mainThread);
long maxProccessTime = 8 * 1000;// 每个任务的最大处理时间
Timer timer = new Timer();
timer.schedule(monitorThread, maxProccessTime);
proccessThread.start();
try {
mainThread.waitLock();
} catch (InterruptedException e) {
e.printStackTrace();
}
proccessThread.stop();
timer.cancel();
System.out.println("end task!" + i);
}
}
}
class MonitorThread extends TimerTask {
private MainThread mt;
public MonitorThread(MainThread mt) {
super();
this.mt = mt;
}
@Override
public void run() {
System.out.println("ThreadID:" + " MonitorThread running!");
mt.notifyLock();
}
}
class ProccessThread implements Runnable {
private MainThread mt;
private Thread thread;
private long processTime;
public ProccessThread(MainThread mt, long processTime) {
super();
this.mt = mt;
this.processTime = processTime;
}
private void doSomething() {
try {
// do something
// thread.sleep(100*1000); //异常情况
// thread.sleep(1*1000); //正常情况
thread.sleep(processTime); // 正常情况
System.out.println("ThreadID:" + thread.getId() + ">>> Normal Process! processTime=" + processTime);
} catch (InterruptedException e) {
// e.printStackTrace();
System.out.println("ThreadID:" + thread.getId() + ">>> AbNormal Proccess! processTime=" + processTime);
}
}
public void run() {
System.out.println("ThreadID:" + thread.getId() + ">>> starting!");
doSomething();
mt.notifyLock();
System.out.println("ThreadID:" + thread.getId() + ">>> ending ok!");
}
public void start() {
thread = new Thread(this);
thread.start();
}
public void stop() {
thread.interrupt();// 如果任务在正常时间内不能退出,认为产生interrupt,强行地退出 (run方法正常结束)
thread.stop();
try {
Thread.sleep(1 * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("ThreadID:" + thread.getId()
+ ">>> stoping end!");
thread = null;
}
}