在实际的情况中可能会需要有的线程是定期执行的,有的线程是只执行一次,如果通过Timer去触发,会涉及线程的切换以及线程安全问题,这对这种情况从jdk1.5开始添加了ScheduledThreadPoolExecutor 组件,这种组件主要就是用来解决前面出现的问题,通过这个组件即可以定期的去执行一个任务,也可以只执行一次,也可以把这两种情况一起使用,为了演示这个组件的使用,写了一个非常简单的小例子:
package com.eric.concurrency;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class ScheduledExecutorSample {
/**
* The ScheduledThreadPoolExecutor provides just the service necessary to
* solve the problem. Using either schedule( ) (to run a task once) or
* scheduleAtFixedRate( ) (to repeat a task at a regular interval), you set
* up Runnable objects to be executed at some time in the future.
*
* @param args
*/
public static ScheduledThreadPoolExecutor se = new ScheduledThreadPoolExecutor(10);
public static void main(String[] args) {
ScheduledExecutorSample ss = new ScheduledExecutorSample();
ss.schedule("begin");
ss.fixedPeriodSchedule();
ss.schedule("end");
}
class Schedule implements Runnable {
private String name;
public Schedule(String name) {
this.name = name;
}
public void run() {
System.out.println("Schedule" + name);
}
}
class FixedSchedule implements Runnable {
public void run() {
System.out.println("Fixed period schedule");
}
}
public void schedule(String name) {
// 设定值执行一次的runnable
se.schedule(new Schedule(name), 0, TimeUnit.SECONDS);
}
public void fixedPeriodSchedule() {
// 设定可以循环执行的runnable,任务的间隔为1秒
se.scheduleAtFixedRate(new FixedSchedule(), 0, 1, TimeUnit.SECONDS);
}
}