java - 未处理的异常？

Question

这个问题已经有答案了:

sleep from main thread is throwing InterruptedException (3 个回答)

已关闭 8 年前。

我花了几个小时试图解决这个问题；我是 Java 新手，我似乎无法找出为什么 java Thread 函数抛出异常错误。谁能给我解释一下吗？

import java.util.Calendar;
import java.util.Date;

public class Loops {

    public static void main(String [] args) {



        Date today = new Date();
        System.out.println(today);

        Calendar cal = Calendar.getInstance();
        cal.set(2015, 1, 1, 0, 3, 0);

        while (today.before(cal.getTime()))
        {
            System.out.println("Waiting");
            Thread.sleep(1000);
            today = new Date();
            System.out.println(today);
        }

        System.out.println("Done");


    }

}

Answer 1

查看Thread.java API，方法sleep();抛出异常。

public static native void sleep(long millis) throws InterruptedException;

因此需要捕获异常或重新抛出异常。

抛出异常

public static void main(String[] args) throws InterruptedException {

        Date today = new Date();
        System.out.println(today);

        Calendar cal = Calendar.getInstance();
        cal.set(2015, 1, 2, 0, 3, 0);

        while (today.before(cal.getTime())) {
            System.out.println("Waiting");
            Thread.sleep(1000);
            today = new Date();
            System.out.println(today);
        }

        System.out.println("Done");

    }

捕获异常

 public static void main(String[] args) {

        Date today = new Date();
        System.out.println(today);

        Calendar cal = Calendar.getInstance();
        cal.set(2015, 1, 2, 0, 3, 0);

        while (today.before(cal.getTime())) {
            System.out.println("Waiting");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            today = new Date();
            System.out.println(today);
        }

        System.out.println("Done");

    }