java捕获线程异常

怼烎@ 2021-06-24 14:35 435阅读 0赞

在jdk1.5之前，线程不允许抛出异常（各个线程要把自己的checked exception处理掉），但是无法避免的是uncheckedexception，也就是RuntimeException，当抛出异常时子线程会结束，但不会影响主线程。主线程通过try catch是无法捕获子线程异常的，Thread对象提供了**setUncaughtExceptionHandler(Thread.UncaughtExceptionHandlereh)方法用来获取线程中产生的异常**。

import java.lang.Thread.UncaughtExceptionHandler;
    
    public class ThreadTest1 {
    
    	public static void main(String[] args) {
    		MyThread my = new MyThread();
    		my.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
    			public void uncaughtException(Thread t, Throwable e) {
    				System.out.println(t.getName() + " : " + e.getMessage());
    				// TODO
    			}
    	    });
    		try {
    			my.start();
    		} catch (Exception e) {
    			System.out.println("error");
    		}
    	}
    	
    	public static class  MyThread extends Thread {
    		public MyThread() {}
    		public void run() {
    		    System.out.println("abc");  
         		throw new RuntimeException("just a test");
    	}
    	}
    }

**注**：下面这种方式无法捕获到线程中抛出的异常。

public static void main(String[] args) {
    	MyThread my = new MyThread();
    	try {
    		my.start();
    	} catch (Exception e) {
    		System.out.println("error");
    	}
    }

在jdk1.5以后，引入了callable，该类可以让线程又返回值，同时可以抛出异常。如下：

public class ThreadTest2 {
    
    	public static void main(String[] args) {
    		ExecutorService pool = Executors.newFixedThreadPool(2); 
    		Callable<String> c1 = new MyThread();
    		Future<String> future = pool.submit(c1);
    		
    		try {
    			System.out.println(future.get());
    		} catch (Exception e) {
    			System.out.println("error....");
    		} finally {
    			pool.shutdown();
    		}
    	}
    	
    	public static class  MyThread implements Callable<String> {
    		public MyThread() {}
    	
    		@Override
    		public String call() throws Exception {
    			int a = 1/0;
    			return "abc";
    		}
    	}
    }