一、延迟队列
延迟队列,底层依赖了优先级队列PriorityBlockingQueue
二、延迟队列案例
(1)延迟队列的任务
public class DelayTask implements Delayed { /**
* 要执行的任务
*/
private String doTask; /**
* 任务要执行的时间
*/
private Date date; /**
* 还剩多长时间,开始执行任务
* @param unit
* @return
*/
@Override
public long getDelay(TimeUnit unit) {
return unit.convert(date.getTime()-System.currentTimeMillis(),unit) ;
} /**
* 当前对象,跟其他延时任务比,谁更先被触发
* @param o
* @return
*/
@Override
public int compareTo(Delayed o) {
if(o instanceof DelayTask){
Date otherDate= ((DelayTask) o).getDate();
long a= date.getTime()-otherDate.getTime();
if(a>0){
return 1;
}else if(a<0){
return -1;
}else{
return 0;
}
}else{
throw new RuntimeException("队列数据异常");
}
} public String getDoTask() {
return doTask;
} public void setDoTask(String doTask) {
this.doTask = doTask;
} public Date getDate() {
return date;
} public void setDate(Date date) {
this.date = date;
}
}
(2)延迟队列的消费线程
public class DelayTaskThread extends Thread{ private DelayQueue<DelayTask> delayTasksQueue; public DelayTaskThread(DelayQueue<DelayTask> delayTasksQueue ){
this.delayTasksQueue=delayTasksQueue;
} @Override
public void run() {
System.out.println("===========线程开始运行=====");
while (true){
try {
DelayTask delayTask=delayTasksQueue.take();
System.out.println(DateFormatUtils.format(new Date(),"yyyy-MM-dd HH:mm:ss")+"获取任务成功");
Date date =delayTask.getDate();
String task=delayTask.getDoTask();
System.out.println(DateFormatUtils.format(new Date(),"yyyy-MM-dd HH:mm:ss")+"=====>要执行的任务内容为【"+task+"】到期时间为【"+ DateFormatUtils.format(date,"yyyy-MM-dd HH:mm:ss")+"】");
Arrays.asList("a","b");
} catch (InterruptedException e) {
e.printStackTrace();
}catch (Exception e){
e.printStackTrace();
}
}
}
}