// 核心线程数
int corePoolSize = 1;
// 最大线程数
int maximumPoolSize = 2;
// 线程存活时间
long keepAliveTime = 10;
// 线程存活时间单位
TimeUnit unit = TimeUnit.SECONDS;
// 有界队列 遵循 FIFO 原则
BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(1);
// 线程工厂
ThreadFactory threadFactory = Executors.defaultThreadFactory();
class TaskThread implements Runnable{
private int i;
public TaskThread(int i) {
this.i = i;
}
@Override
public void run() {
try {
TimeUnit.SECONDS.sleep(2);
System.out.println("执行任务:" + i);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
// 拒绝策略 默认拒绝策略,拒绝任务并抛出异常:
RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();
ThreadPoolExecutor threadPool = new ThreadPoolExecutor(corePoolSize,
maximumPoolSize,
keepAliveTime,
unit,
workQueue,
threadFactory,
handler);
for (int i = 1; i <= 5; i++) {
try {
threadPool.execute(new TaskThread(i));
} catch (Exception e) {
System.out.println("【任务" + i + "】报错:" + e.getMessage());
}
}
【任务】4报错:Task com.test.controller.ThreadPoolController$TaskThread@5c0369c4 rejected from java.util.concurrent.ThreadPoolExecutor@50675690[Running, pool size = 2, active threads = 2, queued tasks = 1, completed tasks = 0]
【任务】5报错:Task com.test.controller.ThreadPoolController$TaskThread@31b7dea0 rejected from java.util.concurrent.ThreadPoolExecutor@50675690[Running, pool size = 2, active threads = 2, queued tasks = 1, completed tasks = 0]
执行任务:1
执行任务:3
执行任务:2
如果提交的任务都要执行,可以将抛出的错误任务存入在redis中,然后定时从redis中获取任务,再提交执行。
RejectedExecutionHandler handler = new ThreadPoolExecutor.CallerRunsPolicy();
执行任务:1
执行任务:4
执行任务:3
执行任务:2
执行任务:5
RejectedExecutionHandler handler = new ThreadPoolExecutor.DiscardPolicy();
执行任务:1
执行任务:3
执行任务:2
RejectedExecutionHandler handler3 = new ThreadPoolExecutor.DiscardOldestPolicy();
执行任务:3
执行任务:1
执行任务:5
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