java主线程捕获子线程中的异常
正常情况下，如果不做特殊的处理，在主线程中是不能够捕获到子线程中的异常的。
例如下面的情况。
package com.xueyou.demo.theadexceptiondemo; public class ThreadExceptionRunner implements Runnable{ @Override public void run() { throw new RuntimeException("error !!!!"); } }
使用线程执行上面的任务
package com.xueyou.demo.theadexceptiondemo; import com.sun.glass.ui.TouchInputSupport; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadFactory; public class ThreadExceptionDemo { public static void main(String[] args) { try { Thread thread = new Thread(new ThreadExceptionRunner()); thread.start(); } catch (Exception e) { System.out.println("========"); e.printStackTrace(); } finally { } System.out.println(123); } }
执行结果如下：
如果想要在主线程中捕获子线程的异常，我们需要使用ExecutorService，同时做一些修改。
如下：
package com.xueyou.demo.theadexceptiondemo; import com.sun.glass.ui.TouchInputSupport; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadFactory; public class ThreadExceptionDemo { public static void main(String[] args) { try { Thread thread = new Thread(new ThreadExceptionRunner()); thread.start(); } catch (Exception e) { System.out.println("========"); e.printStackTrace(); } finally { } System.out.println(123); ExecutorService exec = Executors.newCachedThreadPool(new HandleThreadFactory()); exec.execute(new ThreadExceptionRunner()); exec.shutdown(); } } class MyUncaughtExceptionHandle implements Thread.UncaughtExceptionHandler { @Override public void uncaughtException(Thread t, Throwable e) { System.out.println("caught " + e); } } class HandleThreadFactory implements ThreadFactory { @Override public Thread newThread(Runnable r) { System.out.println("create thread t"); Thread t = new Thread(r); System.out.println("set uncaughtException for t"); t.setUncaughtExceptionHandler(new MyUncaughtExceptionHandle()); return t; } }
这样就能够捕获到异常了，运行结果如下：
上面的方式是设置每一个线程执行时候的异常处理。如果每一个线程的异常处理相同，我们可以用如下的方式进行处理，使用Thread的静态方法。
Thread.setDefaultUncaughtExceptionHandler(new MyUncaughtExceptionHandle());
整体代码如下：
package com.xueyou.demo.theadexceptiondemo; import com.sun.glass.ui.TouchInputSupport; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadFactory; /** * Created by wuxueyou on 2018/6/24. */ public class ThreadExceptionDemo { public static void main(String[] args) { try { Thread thread = new Thread(new ThreadExceptionRunner()); thread.start(); } catch (Exception e) { System.out.println("========"); e.printStackTrace(); } finally { } System.out.println(123); Thread.setDefaultUncaughtExceptionHandler(new MyUncaughtExceptionHandle()); // ExecutorService exec = Executors.newCachedThreadPool(new HandleThreadFactory()); ExecutorService exec = Executors.newCachedThreadPool(); exec.execute(new ThreadExceptionRunner()); exec.shutdown(); } }
运行结果：
