java线程学习之Sleep方法

sleep方法是在线程中常用到的一个方法,它是一个静态方法。

sleep(long millis) 在指定的毫秒数内让当前正在执行的线程休眠（暂停执行），此操作受到系统计时器和调度程序精度和准确性的影响。它可能会抛出中断异常

InterruptedException。它在Thread中定义的为：

    /**
     * Causes the currently executing thread to sleep (temporarily cease
     * execution) for the specified number of milliseconds, subject to
     * the precision and accuracy of system timers and schedulers. The thread
     * does not lose ownership of any monitors.
     *
     * @param  millis
     *         the length of time to sleep in milliseconds
     *
     * @throws  IllegalArgumentException
     *          if the value of {@code millis} is negative
     *
     * @throws  InterruptedException
     *          if any thread has interrupted the current thread. The
     *          <i>interrupted status</i> of the current thread is
     *          cleared when this exception is thrown.
     */
    public static native void sleep(long millis) throws InterruptedException;

sleep(long millis, int nanos)
在指定的毫秒数加指定的纳秒数内让当前正在执行的线程休眠（暂停执行），此操作受到系统计时器和调度程序精度和准确性的影响。

在jdk的Thread中定义如下

 1  /**
 2      * Causes the currently executing thread to sleep (temporarily cease
 3      * execution) for the specified number of milliseconds plus the specified
 4      * number of nanoseconds, subject to the precision and accuracy of system
 5      * timers and schedulers. The thread does not lose ownership of any
 6      * monitors.
 7      *
 8      * @param  millis
 9      *         the length of time to sleep in milliseconds
10      *
11      * @param  nanos
12      *         {@code 0-999999} additional nanoseconds to sleep
13      *
14      * @throws  IllegalArgumentException
15      *          if the value of {@code millis} is negative, or the value of
16      *          {@code nanos} is not in the range {@code 0-999999}
17      *
18      * @throws  InterruptedException
19      *          if any thread has interrupted the current thread. The
20      *          <i>interrupted status</i> of the current thread is
21      *          cleared when this exception is thrown.
22      */
23     public static void sleep(long millis, int nanos)
24     throws InterruptedException {
25         if (millis < 0) {
26             throw new IllegalArgumentException("timeout value is negative");
27         }
28 
29         if (nanos < 0 || nanos > 999999) {
30             throw new IllegalArgumentException(
31                                 "nanosecond timeout value out of range");
32         }
33 
34         if (nanos >= 500000 || (nanos != 0 && millis == 0)) {
35             millis++;
36         }
37 
38         sleep(millis);
39     }

例子一：

 1 package com.song.test;
 2 
 3 import java.util.Date;
 4 
 5 public class TestThread01 extends Thread {
 6     public static void main(String[] args) {
 7         TestThread01 test = new TestThread01();
 8         test.start();
 9     }
10 
11     @Override
12     public void run() {
13         long time1 = System.currentTimeMillis();
14         
15         System.out.println("现在时间" + time1);
16         try {
17             sleep(2000);
18             long time2= System.currentTimeMillis();
19             System.out.println("休眠2秒后" + time2);
20             System.out.println(time2-time1);
21             sleep(1000,500000);
22             long time3 = System.currentTimeMillis();
23             System.out.println("休眠1000.5后：" + time3);
24             System.out.println(time3-time2);//因为时间精度为毫秒，会造成误差
25         } catch (InterruptedException e) {
26             e.printStackTrace();
27         } finally {
28             
29             
30         }
31         
32     }
33 }

运行结果为：

生于忧患，死于安乐