Executor框架与Thread

Executor将线程的创建和线程的执行解耦，比较下面两个例子：

1：TaskExecutionWebServer.java

package chapter06;

import java.io.IOException;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.concurrent.Executor;

import java.util.concurrent.Executors;

public class TaskExecutionWebServer {

    private static final int NTHREADS=100;

    private static final Executor exec = Executors.newFixedThreadPool(NTHREADS);

    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = new ServerSocket(100);

        while (true) {

            final Socket connection=serverSocket.accept();

            Runnable task=new Runnable() {  //Runnable 不处理异常，callable 处理异常。

                @Override

                public void run() {

                    //handlerRequest (connection);

                }

            };

            exec.execute(task);  //将Runnable 交给executor

        }

    }

}

2：ThreadPerTaskWebServer ,不可取。

package chapter06;

import java.io.IOException;

import java.net.ServerSocket;

import java.net.Socket;

/**

 * @program: GradleTestUseSubModule

 * @author: Yafei Li

 * @create: 2018-07-13 21:05

 **/

public class ThreadPerTaskWebServer {

    public static void main(String[] args) throws IOException {

        ServerSocket socket = new ServerSocket(80);

        while (true) {

            final Socket connection=socket.accept();

            Runnable task=new Runnable() {

                @Override

                public void run() {

//                    handleRequest(connection);

                }

            };

            new Thread(task).start();

        }

    }

}

从上面两个例子可以看出 Executors 会创建线程池，从线程池中取出线程执行任务。可以控制线程的数量。

而Thread要为每个任务创建一个线程，浪费资源。开销比较高。

所以Executors 能够将创建线程与任务执行解耦，控制线程数量等优点。

当遇到new Thread(Runnable).start(); 时，应该换为Executor.execute(Runnable);

runnable

Executor框架与Thread