Brief introduction
setDefaultUncaughtExceptionHandler() // Set the global default uncaught error message code
setUncaughtExceptionHandler() // Set the current thread uncaught error message code
If the thread is abnormal, it will execute the set Handler code
demo
The main method depends on the main method. The test() method does not set the thread to capture the wrong information processor, and test2() sets the thread to capture the error information processor.
public class Test01 {
public static void main(String[] args) {
// test(); // 没设置自定义异常的
test2(); //设置自定义异常的
}
/**
* 没设置自定义异常的
*/
private static void test() {
new Thread(new Runnable() {
@Override
public void run() {
System.out.println("子线程异常前");
System.out.println(1 / 0);
}
}).start();
System.out.println("当前线程异常前");
System.out.println(1 / 0);
System.out.println("异常后的代码不能执行"); //发生异常之后 这个代码是不能执行的.
}
/**
* 设置自定义异常
* 如果线程出现了未被捕获的异常,则会执行 uncaughtException方法,
*/
private static void test2() {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("子线程异常前");
System.out.println(1 / 0);
}
});
Thread.UncaughtExceptionHandler currentHandler
= new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
System.out.println("[当前线程的Handler处理器信息] : " + t.toString() + "\n" + e.getMessage());
}
};
/*如果注释下面的,程序出现了未捕获的错误信息不会执行currentHandler方法的代码,
如果有设置setDefaultUncaughtExceptionHandler 就执行该设置的Handler代码.
如果不注释下面的代码,则执行当前线程的未捕获错误信息代码,默认的未捕获错误信息代码(defaultHandler)将不执行
* */
thread.setUncaughtExceptionHandler(currentHandler);//设置未捕获异常处理器
Thread.UncaughtExceptionHandler defaultHandler = new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
StringWriter writer = new StringWriter();
PrintWriter printWriter = new PrintWriter(writer);
printWriter.write("start------------\n");
e.printStackTrace(printWriter);
printWriter.write("------------end");
printWriter.close();
System.out.println("【默认的Handler处理异常信息】" + writer.getBuffer().toString());
}
};
/*如果注释掉,main线程报错会直接打印到控制台,不执行defaultHandler的代码
* 如果不注释,主线程和子线程的未捕获的错误出现都会执行defaultHandler的代码
* */
Thread.setDefaultUncaughtExceptionHandler(defaultHandler);//设置默认未捕获异常处理器
thread.start();
System.out.println("当前线程异常前");
System.out.println(1 / 0);
System.out.println("异常后的代码不能执行"); //发生异常之后 这个代码是不能执行的.
}
}