线程池定义类
package com.nobody;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
/**
* 自定义线程池
* 本实现没考虑空闲线程处理,拒绝策略等,后续再将这部分补上。
* 有兴趣者可以自行实现下。
*
* @author Μr.ηobοdy
*
* @date 2020-06-02
*
*/
public class MyExecutorService {
// 保持一直运行的线程
private List<WorkThread> workThreads;
// 存放未执行任务的队列容器
private final BlockingQueue<Runnable> workQueue;
// 标志线程池关闭与否
private boolean isWorking = true;
// 构造函数,初始化线程池
public MyExecutorService(int corePoolSize, int queueCapacity) {
workThreads = new ArrayList<>(corePoolSize);
workQueue = new LinkedBlockingQueue<>(queueCapacity);
// 提前预热创建固定数量的线程,保持运行状态
for (int i = 0; i < corePoolSize; i++) {
WorkThread workThread = new WorkThread();
workThread.start();
workThreads.add(workThread);
}
}
// 调用execute执行任务,实际上先放入任务队列中
public boolean execute(Runnable task) {
if (null != task) {
return workQueue.offer(task);
}
return false;
}
// 优雅关闭线程池
public void shutdown() {
isWorking = false;
}
// 工作线程类
class WorkThread extends Thread {
@Override
public void run() {
// 如果线程池未关闭,并且任务队列还有未执行任务,则线程不断从任务队列取任务,如果能取到则执行任务的run方法
while (isWorking || !workQueue.isEmpty()) {
Runnable task = workQueue.poll();
if (null != task) {
task.run();
}
}
}
}
}
测试类
package com.nobody;
/**
* 测试线程池
*
* @author Μr.ηobοdy
*
* @date 2020-06-02
*
*/
public class Main {
public static void main(String[] args) {
// 1.创建线程池
MyExecutorService myExecutorService = new MyExecutorService(5, 100);
// 2.创建15个任务
for (int i = 0; i < 15; i++) {
final int finalI = i;
myExecutorService.execute(new Runnable() {
@Override
public void run() {
System.out.println(Thread.currentThread().getName() + " 执行... i=" + finalI);
}
});
}
// 3.关闭线程池
myExecutorService.shutdown();
}
}
测试结果
Thread-0 执行... i=0
Thread-2 执行... i=4
Thread-2 执行... i=6
Thread-4 执行... i=3
Thread-1 执行... i=2
Thread-1 执行... i=9
Thread-3 执行... i=1
Thread-3 执行... i=11
Thread-1 执行... i=10
Thread-4 执行... i=8
Thread-2 执行... i=7
Thread-0 执行... i=5
Thread-4 执行... i=14
Thread-1 执行... i=13
Thread-3 执行... i=12
demo工程下载地址:https://github.com/LucioChn/MyExecutorService.git