自定义线程池
2021-01-06 15:31
标签：实现 ack src 创建线程 活跃 get pre getter 回收 转自：https://www.cnblogs.com/nele/p/6502750.html 当任务提交给ThreadPoolExecutor 线程池中，先检查核心线程数是否已经全部使用， 如果没有交由核心线程去执行任务， 如果核心线程数已经全部占用，则将任务添加到队列里面， 如果队列已经占满，比较当前线程池的中线程的数量是不是与超过maximumPoolSize，如果没有查过则创建线程去执行。 也就是说线程池最多可以接受多少任务呢？就是maximumPoolSize+队列的大小。 当线程池中的线程的数量大于corePoolSize数量有空闲线程则执行回收，回收时间是keepAliveTime，单位是unit，都是初始化的时候设置的。 下面通过代码来说明： 定义一个实现了Runnable接口的类，当作任务类： 定义如下的线程池： 运行结果： 自定义线程池 标签：实现 ack src 创建线程 活跃 get pre getter 回收 原文地址：https://www.cnblogs.com/ylz8401/p/12976102.html线程池执行的流程：
package com.ctrip.ck.test.thread.pool;
public class MyTask implements Runnable {
private int taskId;
private String taskName;
public MyTask(int taskId, String taskName) {
this.taskId = taskId;
this.taskName = taskName;
}
//getter/setter
public int getTaskId() {
return taskId;
}
public void setTaskId(int taskId) {
this.taskId = taskId;
}
public String getTaskName() {
return taskName;
}
public void setTaskName(String taskName) {
this.taskName = taskName;
}
@Override
public void run() {
System.out.println("taskId:" + taskId + ",taskName:" + taskName);
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
private static ThreadPoolExecutor pool = new ThreadPoolExecutor(// 自定义一个线程池
1, // coreSize
2, // maxSize
60, // 60s
TimeUnit.SECONDS,
new ArrayBlockingQueue(3), // 有界队列，容量是3个
Executors.defaultThreadFactory(),
new ThreadPoolExecutor.AbortPolicy()
);
测试类： 1 import java.util.concurrent.ArrayBlockingQueue;
2 import java.util.concurrent.Executors;
3 import java.util.concurrent.ThreadPoolExecutor;
4 import java.util.concurrent.TimeUnit;
5
6 public class PoolTest {
7 private static ThreadPoolExecutor pool = new ThreadPoolExecutor(// 自定义一个线程池
8 1, // coreSize
9 2, // maxSize
10 60, // 60s
11 TimeUnit.SECONDS,
12 new ArrayBlockingQueue(3), // 有界队列，容量是3个
13 Executors.defaultThreadFactory(),
14 new ThreadPoolExecutor.AbortPolicy()
15 );
16
17 public static void main(String[] args) {
18 pool.execute(new MyTask(1, "任务1"));
19 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
20
21 pool.execute(new MyTask(2, "任务2"));
22 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
23
24 pool.execute(new MyTask(3, "任务3"));
25 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
26
27 pool.execute(new MyTask(4, "任务4"));
28 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
29
30 pool.execute(new MyTask(5, "任务5"));
31 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
32
33 pool.execute(new MyTask(6, "任务6"));
34 System.out.println("活跃的线程数：" + pool.getActiveCount() + ",核心线程数：" + pool.getCorePoolSize() + ",线程池大小：" + pool.getPoolSize() + ",队列的大小" + pool.getQueue().size());
35
36 pool.shutdown();
37 System.out.println("------ over ------");
38 }
39
40 }
1 活跃的线程数：1,核心线程数：1,线程池大小：1,队列的大小0
2 活跃的线程数：1,核心线程数：1,线程池大小：1,队列的大小1
3 taskId:1,taskName:任务1
4 活跃的线程数：1,核心线程数：1,线程池大小：1,队列的大小2
5 活跃的线程数：1,核心线程数：1,线程池大小：1,队列的大小3
6 活跃的线程数：2,核心线程数：1,线程池大小：2,队列的大小3
7 Exception in thread "main" taskId:5,taskName:任务5
8 java.util.concurrent.RejectedExecutionException: Task com.ctrip.ck.test.thread.pool.MyTask@3532ec19 rejected from java.util.concurrent.ThreadPoolExecutor@68c4039c[Running, pool size = 2, active threads = 2, queued tasks = 3, completed tasks = 0]
9 at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047)
10 at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823)
11 at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369)
12 at com.ctrip.ck.test.thread.pool.PoolTest.main(PoolTest.java:36)
13 taskId:2,taskName:任务2
14 taskId:3,taskName:任务3
15 taskId:4,taskName:任务4
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