16. Thread pool

Thread Pool

• corePoolSize: The size of the core pool
• maximumPoolSize: maximum number of threads
• keepAliveTime: How long the thread will keep alive when there is no task before it will be terminated
• JDK5.0 provides thread pool related APIs: ExecutorService and Executors
• ExecutorService: The real thread pool interface. Common subclasses of ThreadPoolExecutor
  • void execute(Runnable command) : Execute task/command, no return value, generally used to execute Runnable
  • Futuresubmit(Callabletask): Execute the task, have a return value, and generally execute Callable again
  • void shutdown(): closes the connection pool
• Executors: tool class, thread pool factory class, used to create and return different types of thread pools

Use thread pool

package com.senior;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

// 测试线程池
public class TestPool {
    public static void main(String[] args) {
        // 1.创建服务，创建线程池
        // newFixedThreadPool：参数为线程池大小
        ExecutorService service = Executors.newFixedThreadPool(10);

        // 执行
        service.execute(new MyThread());
        service.execute(new MyThread());
        service.execute(new MyThread());
        service.execute(new MyThread());

        // 2.关闭连接
        service.shutdown();

    }
}
class MyThread implements Runnable{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName());
    }
}