对线程中未捕获的异常进行处理UncaughtExceptionHandler

通常程序中我们会对可能出现的异常进行捕获，例如

public static void main(String[] args) {
    
    System.out.println("##### begin");

    int dividend = 10;
    int divisor = 0;
    try {
        int result = dividend / divisor;
    } catch (Exception e) {
        System.out.println(e);
    }

    System.out.println("##### end");
}

输出结果

##### begin
java.lang.ArithmeticException: / by zero
##### end

如果程序中我们没有对可能出现的异常进行捕获，例如

public static void main(String[] args) {

    System.out.println("##### begin");

    int dividend = 10;
    int divisor = 0;
    int result = dividend / divisor;

    System.out.println("##### end");

}

输出结果

##### begin
Exception in thread "main" java.lang.ArithmeticException: / by zero
    at com.yzj.ehr.controller.InnerController.main(InnerController.java:153)

Thread类有个方法setUncaughtExceptionHandler(UncaughtExceptionHandler eh)，表示我们可以对一个线程自定义自己的未捕获异常处理器。
我们只需写一个类继承UncaughtExceptionHandler接口，重写void uncaughtException(Thread t, Throwable e)方法，然后传入到Thread对象中。

public static void main(String[] args) {

    Thread.currentThread().setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
            System.out.println("这是对未捕获的异常进行处理方法");
            System.out.println("Thread name:" + t.getName() + ",ex:" + e);
        }
    });

    System.out.println("##### begin");

    int dividend = 10;
    int divisor = 0;
    int result = dividend / divisor;

    System.out.println("##### end");

}

输出结果

##### begin
这是对未捕获的异常进行处理方法
Thread name:main,ex:java.lang.ArithmeticException: / by zero

对不同线程定义不同的未捕获异常处理器

public static void main(String[] args) {

    // 定义main线程的
    Thread.currentThread().setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
            System.out.println("这是对main线程中未捕获的异常进行处理方法");
            System.out.println("@ Thread name:" + t.getName() + ",ex:" + e);
        }
    });

    System.out.println("##### begin");
    
    new Thread(new Runnable() {
        @Override
        public void run() {
         // 定义myThread线程的
            Thread.currentThread().setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
                @Override
                public void uncaughtException(Thread t, Throwable e) {
                    System.out.println("这是对myThread线程中未捕获的异常进行处理方法");
                    System.out.println("# Thread name:" + t.getName() + ",ex:" + e);
                }
            });
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e1) {
                e1.printStackTrace();
            }
            // 模拟异常
            int[] array = new int[2];
            int value = array[2];
        }
    }, "myThread").start();

    int dividend = 10;
    int divisor = 0;
    int result = dividend / divisor;

    System.out.println("##### end");

}

输出结果

##### begin
这是对main线程中未捕获的异常进行处理方法
@ Thread name:main,ex:java.lang.ArithmeticException: / by zero
这是对myThread线程中未捕获的异常进行处理方法
# Thread name:myThread,ex:java.lang.ArrayIndexOutOfBoundsException: 2