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手动创建线程次,并自定义线程名称

JAVA相关 开心洋葱 2498次浏览 已收录 0个评论 手机上查看

package com.example.demo;

import com.google.common.util.concurrent.ThreadFactoryBuilder;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import javax.annotation.Nullable;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

/**
* <b><code>Thread</code></b>
* <p>
* Description
* <p>
* <b>Create Time:</b> 2021/9/16 16:39.
*
* @author qd.yt
* @version 0.0.1
* @since cola-demo v0.0.1
*/
public class Thread1 {
// 线程数
public static final int THREAD_POOL_SIZE = Runtime.getRuntime().availableProcessors();;

public static void main(String[] args) throws InterruptedException {
double startT = System.currentTimeMillis();
// 使用 ThreadFactoryBuilder 创建自定义线程名称的 ThreadFactory
//ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat(“hyn-demo-pool-%d”).build();

ThreadFactory namedThreadFactory = new SelfDefinedThreadFactory(“demo-thread”);
// 创建线程池,其中任务队列需要结合实际情况设置合理的容量
ThreadPoolExecutor executor = new ThreadPoolExecutor(THREAD_POOL_SIZE,
THREAD_POOL_SIZE,
0L,
TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<>(1024),
namedThreadFactory,
new ThreadPoolExecutor.AbortPolicy());

// 新建 1000 个任务,每个任务是打印当前线程名称
for (int i = 0; i < 1000; i++) {
executor.execute(() -> System.out.println(Thread.currentThread().getName()));
}
// 优雅关闭线程池
executor.shutdown();
executor.awaitTermination(1000L, TimeUnit.SECONDS);
// 任务执行完毕后打印”Done”
System.out.println(“Done”);
double startE = System.currentTimeMillis();
System.out.println(“”+(startE-startT));
}

static class SelfDefinedThreadFactory implements ThreadFactory {
final AtomicInteger threadNumber = new AtomicInteger(1);
final String namePrefix;

SelfDefinedThreadFactory(String namePrefix) {
this.namePrefix = namePrefix+”-“;
}

@Override
public Thread newThread(@Nullable Runnable r) {
Thread t = new Thread( r,namePrefix + threadNumber.getAndIncrement());
if (t.isDaemon()) {
t.setDaemon(true);
}
if (t.getPriority() != Thread.NORM_PRIORITY) {
t.setPriority(Thread.NORM_PRIORITY);
}
return t;
}
}
}


也可以使用谷歌的工具类增加依赖:

com.google.guava
guava
30.1.1-jre

执行改进版,可以增加详细日志


package com.example.demo;


import com.google.common.util.concurrent.ThreadFactoryBuilder;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import javax.annotation.Nullable;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * <b><code>Thread</code></b>
 * <p>
 * Description
 * <p>
 * <b>Create Time:</b> 2021/9/16 16:39.
 *
 * @author qd.yt
 * @version 0.0.1
 * @since cola-demo v0.0.1
 */
public class Thread1 {
    // 线程数
    public static final int THREAD_POOL_SIZE = Runtime.getRuntime().availableProcessors();;

    public static void main(String[] args) throws InterruptedException {
        double startT = System.currentTimeMillis();
        // 使用 ThreadFactoryBuilder 创建自定义线程名称的 ThreadFactory
        //ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat("hyn-demo-pool-%d").build();

        ThreadFactory namedThreadFactory = new SelfDefinedThreadFactory("demo-thread");
        // 创建线程池,其中任务队列需要结合实际情况设置合理的容量
        ThreadPoolExecutor executor = new ThreadPoolExecutor(THREAD_POOL_SIZE,
                THREAD_POOL_SIZE,
                0L,
                TimeUnit.MILLISECONDS,
                //队列改小后,会出现rejected,不接受执行任务的日志
                new LinkedBlockingQueue<>(2),
                namedThreadFactory,
                new MyIgnorePolicy());
        executor.prestartAllCoreThreads(); // 预启动所有核心线程

        // 新建 1000 个任务,每个任务是打印当前线程名称
        for (int i = 0; i < 1000; i++) {
            MyTask task = new MyTask(String.valueOf(i));
            executor.execute(task);
        }
        // 优雅关闭线程池
        executor.shutdown();
        executor.awaitTermination(1000L, TimeUnit.SECONDS);
        // 任务执行完毕后打印"Done"
        System.out.println("Done");
        double startE = System.currentTimeMillis();
        System.out.println(""+(startE-startT));
    }

    public static class MyIgnorePolicy implements RejectedExecutionHandler {

        @Override
        public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
            doLog(r, e);
        }

        private void doLog(Runnable r, ThreadPoolExecutor e) {
            // 可做日志记录等
            System.err.println( r.toString() + " rejected");
            //System.out.println("completedTaskCount: " + e.getCompletedTaskCount());
        }
    }

    static class MyTask implements Runnable {
        private String name;

        public MyTask(String name) {
            this.name = name;
        }

        @Override
        public void run() {
            try {
                System.out.println(this.toString() + " is running!");
                Thread.sleep(3000); //让任务执行慢点
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        public String getName() {
            return name;
        }

        @Override
        public String toString() {
            return "MyTask [name=" + name + "]";
        }
    }

    /**
     * 自定义线程名
     */
    static class SelfDefinedThreadFactory implements ThreadFactory {
        final AtomicInteger threadNumber = new AtomicInteger(1);
        final String namePrefix;

        SelfDefinedThreadFactory(String namePrefix) {
            this.namePrefix = namePrefix+"-";
        }

        @Override
        public Thread newThread(@Nullable Runnable r) {
            Thread t = new Thread( r,namePrefix + threadNumber.getAndIncrement());
            if (t.isDaemon()) {
                t.setDaemon(true);
            }
            if (t.getPriority() != Thread.NORM_PRIORITY) {
                t.setPriority(Thread.NORM_PRIORITY);
            }
            System.out.println(t.getName() + " has been created");
            return t;
        }
    }
}

扩展阅读:

两种情况会拒绝处理任务:

1):当线程数已经达到maxPoolSize,且队列已满,会拒绝新任务;

2):当线程池调用shutdown()后,会等待队列里的任务执行完毕,再关闭。如果在调用shutdown()和线程池真正关闭之间提交任务,会拒绝新任务;

 

线程池会调用rejectedExecutionHandler来处理这个任务。如果没有设置默认是 AbortPolicy,会抛出异常

线程池提供的拒绝策略:

ThreadPoolExecutor.AbortPolicy:丢弃任务,抛运行时异常

ThreadPoolExecutor.CallerRunsPolicy:执行任务

ThreadPoolExecutor.DiscardPolicy:忽视,什么都不会发生

ThreadPoolExecutor.DiscardOldestPolicy:从队列中踢出最先进入队列(最后一个执行)的任务

实现RejectedExecutionHandler接口,可自定义处理器


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