TimeUnit 使用

1.TimeUnit的介绍
是java.util.concurrent包下面的一个类

2.TimeUnit的作用

时间颗粒度转换
延时
3.TimeUnit常用的颗粒度

TimeUnit.DAYS          //天TimeUnit.HOURS         //小时TimeUnit.MINUTES       //分钟TimeUnit.SECONDS       //秒TimeUnit.MILLISECONDS  //毫秒 

4. 时间颗粒度转换

public long toMillis(long d)    //转化成毫秒public long toSeconds(long d)  //转化成秒public long toMinutes(long d)  //转化成分钟public long toHours(long d)    //转化成小时public long toDays(long d)     //转化天

5. 时间颗粒度转换的例子

package com.westlife;import java.util.concurrent.TimeUnit;/** * @Author: westlife * @Description: * @Date: Created in 15:17 2017/12/21 */public class TestTimeUnit {    public static void main(String[] args) {        //1天有24个小时    1代表1天：将1天转化为小时        System.out.println( TimeUnit.DAYS.toHours( 1 ) );        //结果： 24        //1小时有3600秒        System.out.println( TimeUnit.HOURS.toSeconds( 1 ));        //结果3600        //把3天转化成小时        System.out.println( TimeUnit.HOURS.convert( 3 , TimeUnit.DAYS ) );        //结果是：72    }}

6. 延时

• Thread.sleep();

package com.westlife;/** * @Author: westlife * @Description: * @Date: Created in 15:25 2017/12/21 */public class TestTime2 {    public static void main(String[] args) {        new Thread( new Runnable() {            @Override            public void run() {                try {                    Thread.sleep( 5 * 1000 );                    System.out.println( "5秒延时完成了");                } catch (InterruptedException e) {                    e.printStackTrace();                }            }        }).start();  ;    }}

• TimeUnit 的延时

package com.westlife;import java.util.concurrent.TimeUnit;/** * @Author: westlife * @Description: * @Date: Created in 15:29 2017/12/21 */public class TestTime3 {    public static void main(String[] args) {        new Thread( new Runnable() {            @Override            public void run() {                try {                    TimeUnit.SECONDS.sleep( 5 );                    System.out.println( "延时5秒，完成了");                } catch (InterruptedException e) {                    e.printStackTrace();                }            }        }).start();  ;    }}