java简单实现多线程及线程池实例详解

时间:2021-08-13 22:04:36

本文为大家分享了java多线程的简单实现及线程池实例,供大家参考,具体内容如下

一、多线程的两种实现方式

1、继承Thread类的多线程

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/**
 * 继承Thread类的多线程简单实现
 */
public class extThread extends Thread {
    
   public void run(){
      for(int i=0;i<100;i++){
        System.out.println(getName()+"-"+i);
      }
   }
    
   public static void main(String arg[]){
      for(int i=0;i<100;i++){
        System.out.println(Thread.currentThread().getName()+"-"+i);
        if(i==50){
           new extThread().start();
           new extThread().start();
        }
      }
   }
}

2、实现Runnable接口的多线程

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/**
 * 实现runable接口的多线程实例
 */
public class runThread implements Runnable {
   public void run(){
      for(int i=0;i<100;i++){
        System.out.println(Thread.currentThread().getName()+"-"+i);
      }
   }
    
   public static void main(String arg[]){
      for(int i=0;i<100;i++){
        System.out.println(Thread.currentThread().getName()+"-"+i);
        if(i==50){
           runThread rt = new runThread();
           new Thread(rt,"新线程1").start();
           new Thread(rt,"新线程2").start();
        }
      }
   }
    
}

二、线程池的简单实现

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//实现Runnable接口
class TestThread implements Runnable{
   
  public void run() {
    for(int i = 0;i < 100;i++){
      System.out.println(Thread.currentThread().getName() + "i的值为:" + i);
    }
  }
}
 
public class threadPoolTest {
   
  public static void main(String[] args) {
    //创建一个具有固定线程数的线程池
    ExecutorService pool = Executors.newFixedThreadPool(5);
    //向线程池中提交三个线程
    pool.submit(new TestThread());
    pool.submit(new TestThread());
    pool.submit(new TestThread());
    //关闭线程池
    pool.shutdown();
  }
 
}

三、java爬虫使用线程池实例

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/**
 * 爬虫调度线程池
 */
public class threadPool {
 
  public static HashMap<String, Spiders> statusMap = new HashMap<String, Spiders>();
  // 存放爬虫,key为爬虫的id,value为爬虫的线程池
  static HashMap<Integer, ThreadPoolExecutor> threadMap = new HashMap<Integer, ThreadPoolExecutor>();
  //创建一个线程池
  static ThreadPoolExecutor threadPool = new ThreadPoolExecutor(200, 230,80000L, 
      TimeUnit.SECONDS, 
      new ArrayBlockingQueue<Runnable>(10),
      new ThreadPoolExecutor.CallerRunsPolicy());
 
  public static void executeThread(Spiders spider) {
    statusMap.put(String.valueOf(spider.getId()), spider);
    // 爬虫有效
    if (spider.getFlag() == 0) {
      if (spider.getStatus() == 0) {
        // 表示爬虫进入抓取状态
        ThreadPoolExecutor detailPool = null;
        if (threadMap.get(spider.getId()) == null) {
          detailPool = new ThreadPoolExecutor(30, 80, 80000L,
              TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(
                  10),
              new ThreadPoolExecutor.CallerRunsPolicy());
          threadMap.put(spider.getId(), detailPool);
          threadPool.execute(new threadRun(spider, threadMap));
        }
      }
    }
  }
}
 
//实现Runnable接口
class threadRun implements Runnable {
 
  private HashMap<Integer, ThreadPoolExecutor> threadPoolMap;
  private Spiders spider;
 
  public threadRun(Spiders spider,
      HashMap<Integer, ThreadPoolExecutor> threadPoolMap) {
    this.threadPoolMap = threadPoolMap;
    this.spider = spider;
  }
 
  //线程执行体
  public void run() {
    try {
      if ("rong360".equals(spider.getWebsite())) {
        new RongThread(threadPoolMap.get(spider.getId()), spider)
            .startSpider();
      } else if ("xxgg_sd".equals(spider.getWebsite())) {
        new Spider_ShanDong(threadPoolMap.get(spider
            .getId()), spider).startSpider();
      } else if ("xxgg_gz".equals(spider.getWebsite())) {
        new Spider_GuiZhou(threadPoolMap.get(spider
            .getId()), spider).startSpider();
      } else if ("sx".equals(spider.getWebsite())) {
        new SpiderSX(spider).startSpider();
      } else if ("baidu".equals(spider.getWebsite())) {
        new SpiderBaiDu(spider).startSpider();
      } else if ("11315".equals(spider.getWebsite())) {
        new Spider11315ByName(spider).startSpider();
      
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
 
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:https://blog.csdn.net/William_hangshao/article/details/67644335