多线程

1、创建线程

• 方式一

  继承Thread类，重写run()方法，调用start方法开启线程

  package com.study;
  
  public class TestThread extends Thread{
      public void run(){
          for (int i = 0; i < 100; i++) {
              System.out.println("hello world"+i);
  
          }
      }
  
      public static void main(String[] args) {
          //main线程,主线程
          TestThread testThread = new TestThread();
          testThread.start();
  
          for (int i = 0; i < 200; i++) {
              System.out.println("我是主线程"+i);
  
          }
      }
  }
  
  

• 方式二

  实现Runnable接口

  package com.study;
  
  public class TestRunnable implements Runnable{
      @Override
      public void run() {
          for (int i = 0; i < 30; i++) {
  
              System.out.println("hello world"+i);
  
          }
      }
  
      public static void main(String[] args) {
          TestRunnable testRunnable = new TestRunnable();
          new Thread(testRunnable).start();
  
          for (int i = 0; i < 60; i++) {
              System.out.println("主线程"+i);
          }
      }
  }
  
  

  2.练习1： 实现多线程同步下载图片

  package com.study;
  
  import org.apache.commons.io.FileUtils;
  import org.omg.CORBA.StringHolder;
  
  import java.io.File;
  import java.io.IOException;
  import java.net.URL;
  
  public class TestThread2 extends Thread{
      private String url; //图片地址名
      private String name;  //定义图片名
  
      public TestThread2(String url, String name){
          this.url = url;
          this.name = name;
      }
  
      public void run(){
          WebDownloader webDownloader = new WebDownloader();
          webDownloader.downloader(url,name);
          System.out.println("下载文件名："+name);
      }
  
      public static void main(String[] args) {
          TestThread2 t1 = new TestThread2("https://img2020.cnblogs.com/blog/1887105/202103/1887105-20210312200240114-635118268.png","1.png"); 
          TestThread2 t2 = new TestThread2("https://img2020.cnblogs.com/blog/1887105/202103/1887105-20210312200300521-827686531.png","2.png");
          t1.start();
          t2.start();
      }
  
  }
  //下载器
  class WebDownloader{
      public void downloader(String url,String name){
          try {
              FileUtils.copyURLToFile(new URL(url),new File(name));
          } catch (IOException e) {
              e.printStackTrace();
              System.out.println("捕获异常");
          }
  
      }
  }
  
  

  3.练习2：龟兔赛跑

  package com.study;
  
  public class Race implements Runnable{
  
      private static String winner;  //静态变量
      @Override
      public void run() {
          //100米赛道
          for (int i = 1; i <= 100; i++) {
              System.out.println(Thread.currentThread().getName()+"跑了"+i+"米");
              if (gameOver(i)){
                  break;
              }
              if (Thread.currentThread().getName().equals("rabbit") && i%10==0){
                  try {
                      Thread.sleep(10);
                  } catch (InterruptedException e) {
                      e.printStackTrace();
                  }
              }
  
          }
  
  
      }
  
      //判断游戏结束
      public boolean gameOver(int step){
          boolean flag=false;
          if (step >= 100){
              winner = Thread.currentThread().getName();
              System.out.println("winner is "+winner);
          }
          if (winner!=null){
              flag = true;
          }
          return flag;
      }
  
      public static void main(String[] args) {
          //一条赛道
          Race race = new Race();
  
          new Thread(race,"rabbit").start();
          new Thread(race,"turtle").start();
  
  
      }
  
  
  }
  
  

  4.静态代理模式

  package com.study;
  //静态代理模式
  public class StaticProx {
  }
  
  interface Marry{
  
      public void HappyMarry();
  }
  
  class You implements Marry{
  
      @Override
      public void HappyMarry() {
          System.out.println("I'm very happy!");
      }
  }
  
  class WeddingCompany implements Marry{
  
      private  Marry target;
      WeddingCompany(Marry target){
          this.target = target;
      }
      @Override
      public void HappyMarry() {
  
          before();
          this.target.HappyMarry();
          after();
      }
  
      private void after() {
          System.out.println("结婚后，收尾款");
      }
  
      private void before(){
          System.out.println("结婚前，布置现场");
      }
  
      public static void main(String[] args) {
  //        You you = new You();
  //        WeddingCompany weddingCompany = new WeddingCompany(you);
  
          WeddingCompany weddingCompany = new WeddingCompany(new You());
          weddingCompany.HappyMarry();
      }
  }