Java并发编程：ThreadPoolExecutor常用线程池_throw new runtimeerrorexception(null);

目录

线程池的分类

常用线程池(ThreadPoolExecutor)示例

CachedThreadPool

FixedThreadPool

SingleThreadExecutor

ThreadPoolExecutor类分析

三种线程池(返回ThreadPoolExecutor)构造方法

ThreadPoolExecutor中的成员变量

三种线程池(返回ThreadPoolExecutor类)分析

execute与submit方法

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线程池的分类

所有实现了ExecutorService接口(Executor的子接口)的实现类都是线程池，可以分为三大类

• ForkJoinPool
• ScheduledThreadPoolExecutor
• ThreadPoolExecutor

 

具体的线程池，在工具类Executors中预创建了六小类

实现了ThreadPoolExecutor类：

• ExecutorService newCachedThreadPool()：无界线程池
• ExecutorService newFixedThreadPool()：有界线程池
• ExecutorService newSingleThreadExecutor()：单一线程池

实现了ScheduledThreadPoolExecutor类：

• ScheduledExecutorService newSingleThreadScheduledExecutor() 
• ScheduledExecutorService newScheduledThreadPool(int corePoolSize)

实现了ForkJoinPool类： 

• ExecutorService newWorkStealingPool()  

 

当然我们也可以自定义线程池

 

常用线程池(ThreadPoolExecutor)示例

现在有一个任务WorkTask

public class WorkTask implements Runnable{
	public void run() {
		try {
			int r = (int)(Math.random()*10);
			Thread.sleep(r*1000);
			System.out.println(Thread.currentThread().getId() + " is over");
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

CachedThreadPool

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
public class CachedThreadPoolTest {
	public static void main(String[] args) {
		ExecutorService exec = Executors.newCachedThreadPool();
		for(int i=0;i<20;i++){
			exec.execute(new WorkTask());
		}
		exec.shutdown();
	}
}

无界线程池，最多可创建Integer.MAX_VALUE个线程，运行结果没有重复的线程号

FixedThreadPool

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
public class FixedThreadPoolTest {
	public static void main(String[] args) {
		ExecutorService exe