在多线程中会出现异常情况发生, 但是又苦于没有任何日志信息, 这对程序员来说拍错是个致命的打击, 不小心需要好几天都没有眉目
针对这种情况, 对JDK自带的线程池进行改造, 让其能够显示出对应的错误日志,
创建TraceThreadPoolExecutor extends ThreadPoolExecutor (JDK自带线程池)
import java.util.concurrent.*;
/**
* Created by Luoqy on 2017/7/9 0009.
*/
public class TraceThreadPoolExecutor extends ThreadPoolExecutor {
public TraceThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
}
@Override
public void execute(Runnable task){
super.execute(warp(task, clientTrace(), Thread.currentThread().getName()));
}
@Override
public Future<?> submit(Runnable task){
return super.submit(warp(task, clientTrace(), Thread.currentThread().getName()));
}
private Exception clientTrace(){
return new Exception("Client stack trace");
}
private Runnable warp(final Runnable task, final Exception clientStack, String clientThreadName) {
return new Runnable() {
@Override
public void run() {
try {
task.run();
} catch (Exception e) {
clientStack.printStackTrace();
throw e;
}
}
};
}
以上warp()方法的第2个参数为一个异常信息,里面保存提交任务的线程中的堆栈信息, 该方法将我们传入的Runnable任务进一步进行包装, 使之能处理异常信息,当异常发生时将会进行异常信息打印
测试Demo展示:
创建一个除法运算的任务
public class DivTask implements Runnable {
int a;
int b;
public DivTask(int a, int b) {
this.a = a;
this.b = b;
}
@Override
public void run() {
double re = a / b;
System.out.println(re);
}
}
测试
public static void main(String[] args) {
TraceThreadPoolExecutor pools = new TraceThreadPoolExecutor(0, Integer.MAX_VALUE, 0L, TimeUnit.SECONDS, new SynchronousQueue<Runnable>());
for (int i = 0; i < 5; i++) {
pools.execute(new DivTask(100, i));
}
}
运行之后你将看到错误提示信息:
100.0
java.lang.Exception: Client stack trace
25.0
50.0
at com.beingmate.vip.controller.TraceThreadPoolExecutor.clientTrace(TraceThreadPoolExecutor.java:29)
33.0
at com.beingmate.vip.controller.TraceThreadPoolExecutor.execute(TraceThreadPoolExecutor.java:17)
at com.beingmate.vip.controller.TraceThreadPoolExecutor.main(TraceThreadPoolExecutor.java:51)
Exception in thread "pool-1-thread-1" java.lang.ArithmeticException: / by zero
at com.beingmate.vip.controller.DivTask.run(DivTask.java:17)
at com.beingmate.vip.controller.TraceThreadPoolExecutor$1.run(TraceThreadPoolExecutor.java:38)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
备注:
pools.execute() 和 pools.submit().get()方法也可以打印出部分堆栈信息, 但是无法知道是哪个线程出现问题
