java基础-并发-如何捕获线程异常

由于线程本质特性，使得我们不能捕获从线程中逃逸的异常。一旦异常逃出线程的run方法，他就会向外传播到控制台。
捕获线程中异常分为以下几步：
新建线程异常处理器，实现Thread.UncaughtExceptionHandler接口

class MyUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler{    @Override    public void uncaughtException(Thread t, Throwable e) {        System.out.println("catch " + e);    }}

创建线程工厂，给每一个由此工厂生产的线程都设置线程处理器：

class HandlerThreadFactory implements ThreadFactory{    @Override    public Thread newThread(Runnable r) {        System.out.println(this+" creating new Thread");        Thread t  = new Thread(r);        System.out.println(" created " + t);        //设置线程处理器        t.setUncaughtExceptionHandler(new MyUncaughtExceptionHandler());        System.out.println("eh= "+t.getUncaughtExceptionHandler());        return t;    }}

创建线程：

class ExceptionThread implements Runnable{    @Override    public void run() {        Thread t = Thread.currentThread();        System.out.println("run() by "+ t);        System.out.println("eh= " +t.getUncaughtExceptionHandler());        throw new RuntimeException();    }}

使用测试：

public class CaptureUnCaughtException {    public static void main(String[] args) {        ExecutorService exec = Executors.newCachedThreadPool(new HandlerThreadFactory());        exec.execute(new ExceptionThread());    }}

输出(不一定完全一样)：

com.len.javabase.supervene.base.HandlerThreadFactory@4e25154f creating new Thread created Thread[Thread-0,5,main]eh= com.len.javabase.supervene.base.MyUncaughtExceptionHandler@70dea4erun() by Thread[Thread-0,5,main]eh= [e-mail]@4e25154f creating new Thread created Thread[Thread-1,5,main]eh= com.len.javabase.supervene.base.MyUncaughtExceptionHandler@471be934catch java.lang.RuntimeException