线程_线程池

1.认识Executor接口最顶层接口

package com.hpd.executor;

import java.util.concurrent.Executor;

public class T01_MyExecutor implements Executor {

    public static void main(String[] args) {
        new T01_MyExecutor().execute(()->System.out.println("helllo executor"));
    }

    @Override
    public void execute(Runnable command) {
        //new Thread(command).start();//开启一个线程去调用
        command.run();//直接的方法调用
    }

}

2.ExecutorService接口（继承自Executor接口）

　　除了继承的executor（）方法外，还提供了submit（Callable<T> task）方法,submit(Runnable task)

3Executors工具类

4ThreadPool

package com.hpd.executor;

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

import javax.swing.plaf.synth.SynthSplitPaneUI;

public class T02_ThreadPool {

    public static void main(String[] args) throws InterruptedException {
        ExecutorService service = Executors.newFixedThreadPool(5);
        for(int i=0;i<6;i++) {
            service.execute(()->{
                try {
                    TimeUnit.MICROSECONDS.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName());
            });
        }
        System.out.println(service);
        
        service.shutdown();
        System.out.println(service.isTerminated());
        System.out.println(service.isShutdown());
        System.out.println(service);
        
        TimeUnit.MICROSECONDS.sleep(5000);
        System.out.println(service.isTerminated());
        System.out.println(service.isShutdown());
        System.out.println(service);
        
        
    }

}

java.util.concurrent.ThreadPoolExecutor@1b28cdfa[Running, pool size = 5, active threads = 5, queued tasks = 1, completed tasks = 0]
false
true
java.util.concurrent.ThreadPoolExecutor@1b28cdfa[Shutting down, pool size = 5, active threads = 5, queued tasks = 1, completed tasks = 0]
pool-1-thread-2
pool-1-thread-4
pool-1-thread-1
pool-1-thread-5
pool-1-thread-3
pool-1-thread-2
true
true
java.util.concurrent.ThreadPoolExecutor@1b28cdfa[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 6]

5FutureTask和Future

package com.hpd.executor;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;

public class T03_Future {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        FutureTask<Integer> task = new FutureTask<>(()-> {   //用FurureTask包装Callable任务
            TimeUnit.MILLISECONDS.sleep(500); //Thread只能传入FutureTask不能传入Callable
            return 1000;
        });
        new Thread(task).start();
        System.out.println(task.get());//阻塞
        
        ExecutorService service = Executors.newFixedThreadPool(5);
        Future<Integer> f= service.submit(()->{ //submit方法直接传入Callable任务
            TimeUnit.MICROSECONDS.sleep(500);
            return 1;
        });
        System.out.println(f.isDone());
        
    }

}

6.------

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