简单的java线程池demo
2019-10-10 本文已影响0人
Mrhy1996
最近看课程,简单的写了一个线程池的demo,代码如下
package com.mrhy.threaddemo.p2;
import com.sun.corba.se.spi.orbutil.threadpool.Work;
import lombok.extern.log4j.Log4j2;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
@Log4j2
public class FixedSizeThreadPool {
//手写线程池需要准备什么?
// 1.需要1个仓库
private BlockingQueue<Runnable> blockingQueue;
// 2.需要一个线程的集合
private List<Thread> workers;
//3. 需要具体干活的线程
public static class Worker extends Thread {
// 图上的卡车
// 1.到我们的仓库中去拿东西(blockingQueue)
//
private FixedSizeThreadPool pool;
// 创建构造方法,声明自己属于哪个线程池
public Worker(FixedSizeThreadPool pool) {
this.pool = pool;
}
@Override
public void run() {
// 开始工作
while (this.pool.isWorking || this.pool.blockingQueue.size() > 0) {
Runnable task = null;
// 从队列中拿东西的时候,需要的是阻塞
try {
if (this.pool.isWorking) {
task = this.pool.blockingQueue.take();
} else {
task = this.pool.blockingQueue.poll();
}
} catch (Exception e) {
e.printStackTrace();
}
if (task != null) {
task.run();
log.info("线程:{}执行完毕", Thread.currentThread().getName());
// System.out.println("线程:"+Thread.currentThread().getName());
}
}
}
}
// 线程池的初始化,构造函数
public FixedSizeThreadPool(int poolSize, int taskSize) {
if (poolSize <= 0 || taskSize <= 0)
throw new IllegalArgumentException("非法参数");
this.blockingQueue = new LinkedBlockingQueue<>(taskSize);
this.workers = Collections.synchronizedList(new ArrayList<>());
for (int i = 0; i < poolSize; i++) {
Worker work = new Worker(this);
work.start();
workers.add(work);
}
}
// 把任务提交到仓库中的办法
public boolean submit(Runnable task) {
if (isWorking) {
return this.blockingQueue.offer(task);
} else {
return false;
}
}
// 关闭的方法:
//a.仓库停止接收任务
//b.一旦仓库中还有任务就要继续执行
//c. 拿任务就不该阻塞
//d.一旦任务阻塞,我就中断他
private volatile boolean isWorking = true;
public void shutDown() {
// 执行关闭即可
this.isWorking = false;
for (Thread thread : workers) {
if (thread.getState().equals(Thread.State.BLOCKED)) {
thread.interrupt();// 中断线程
}
}
}
public static void main(String[] args) {
FixedSizeThreadPool fixedSizeThreadPool = new FixedSizeThreadPool(3, 6);
for (int i = 0; i < 6; i++) {
fixedSizeThreadPool.submit(
new Runnable() {
@Override
public void run() {
System.out.println("放入线程");
try {
Thread.sleep(2000L);
} catch (InterruptedException e) {
e.printStackTrace();
log.error("一个线程被中断");
}
}
}
);
}
fixedSizeThreadPool.shutDown();
}
}