当线程抛出一个未捕获到的异常时,jvm将为异常寻找以下三种可能的处理器。
首先,它查找线程对象的未捕获异常处理器,如果找不到,jvm继续查找线程对象所在的线程组的未捕获异常处理器,如果还是找不到,会继续查找默认的未捕获异常处理器。
如果没有一个异常处理器在,jvm会把堆栈异常记录打印到控制台,并退出程序。
public class ThreadCatchException implements UncaughtExceptionHandler{
@Override
public void uncaughtException(Thread t, Throwable e) {
System.out.println(t.getName()+"出现异常");
}
public static void main(String[] args) {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
int a = 1/0;
}
});
thread.setUncaughtExceptionHandler(new ThreadCatchException());
thread.start();
}
}
输出结果:
Thread-0出现异常
import java.lang.Thread.UncaughtExceptionHandler;
public class ThreadCatchException implements UncaughtExceptionHandler {
@Override
public void uncaughtException(Thread t, Throwable e) {
System.out.println(t.getName() + "出现异常");
}
public static void main(String[] args) {
ThreadGroup threadGroup = new ThreadGroup("threadGroup") {
@Override
public void uncaughtException(Thread t, Throwable e) {
// TODO Auto-generated method stub
System.out.println(t.getName() + "出现异常");
}
};
for (int i = 0; i < 5; i++) {
Thread thread = new Thread(threadGroup, new Runnable() {
@Override
public void run() {
int a = 1 / 0;
}
});
thread.start();
}
}
}
输出结果:
Thread-0出现异常
Thread-2出现异常
Thread-1出现异常
Thread-4出现异常
Thread-3出现异常