java多线程相关介绍-白红宇

java多线程相关介绍

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发布时间：2019-05-23

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1.线程的创建

三种创建线程的方法：

通过实现 Runnable 接口

以下的代码文件名RunnableDemo.java

package com.company;class RunnableDemo implements Runnable {
      private Thread t;   private String threadName;      RunnableDemo( String name) {
         threadName = name;      System.out.println("Creating " +  threadName );   }      public void run() {
         System.out.println("Running " +  threadName );      try {
            for(int i = 4; i > 0; i--) {
               System.out.println("Thread: " + threadName + ", " + i);            // 让线程睡眠一会            Thread.sleep(50);         }      }catch (InterruptedException e) {
            System.out.println("Thread " +  threadName + " interrupted.");      }      System.out.println("Thread " +  threadName + " exiting.");   }      public void start () {
         System.out.println("Starting " +  threadName );      if (t == null) {
            t = new Thread (this, threadName);         t.start ();      }   }}

以下的代码文件名TestThread .java

package com.company;public class TestThread {
       public static void main(String args[]) {
         RunnableDemo R1 = new RunnableDemo( "Thread-1");      R1.start();            RunnableDemo R2 = new RunnableDemo( "Thread-2");      R2.start();   }   }

通过继承 Thread 类本身

以下的代码文件名ThreadDemo.java

class ThreadDemo extends Thread {
      private Thread t;   private String threadName;      ThreadDemo( String name) {
         threadName = name;      System.out.println("Creating " +  threadName );   }      public void run() {
         System.out.println("Running " +  threadName );      try {
            for(int i = 4; i > 0; i--) {
               System.out.println("Thread: " + threadName + ", " + i);            // 让线程睡眠一会            Thread.sleep(50);         }      }catch (InterruptedException e) {
            System.out.println("Thread " +  threadName + " interrupted.");      }      System.out.println("Thread " +  threadName + " exiting.");   }      public void start () {
         System.out.println("Starting " +  threadName );      if (t == null) {
            t = new Thread (this, threadName);         t.start ();      }   }}

以下的代码文件名TestThread.java

public class TestThread {
       public static void main(String args[]) {
         ThreadDemo T1 = new ThreadDemo( "Thread-1");      T1.start();            ThreadDemo T2 = new ThreadDemo( "Thread-2");      T2.start();   }   }

通过 Callable 和 Future 创建线程

public class CallableThreadTest implements Callable
   
     {
       public static void main(String[] args)      {
             CallableThreadTest ctt = new CallableThreadTest();          FutureTask
    
      ft = new FutureTask<>(ctt);          for(int i = 0;i < 100;i++)          {
                 System.out.println(Thread.currentThread().getName()+" 的循环变量i的值"+i);              if(i==20)              {
                     new Thread(ft,"有返回值的线程").start();              }          }          try          {
                 System.out.println("子线程的返回值："+ft.get());          } catch (InterruptedException e)          {
                 e.printStackTrace();          } catch (ExecutionException e)          {
                 e.printStackTrace();          }        }    @Override      public Integer call() throws Exception      {
             int i = 0;          for(;i<100;i++)          {
                 System.out.println(Thread.currentThread().getName()+" "+i);          }          return i;      }  }