Java线程基础 之 创建线程

Java 线程基础 之 创建线程 继承Thread类创建线程

• 自定义Thread

  public class MyThread extends Thread {
      @Override
      public void run() {  //通过Thread类把run方法包装成线程体
          System.out.println(getName() + " *");
          try {
              Thread.sleep(1000);
          } catch (InterruptedException e) {
              e.printStackTrace();
          }
          System.out.println(getName() + "  #");
      }
  }
  

• 测试代码

public static void main(String[] args) {
    System.out.println(Thread.currentThread().getName());
    new MyThread().start();
    new MyThread().start();
    new MyThread().start();
}

结果：

实现Runnable接口创建线程

步骤：

1. 创建一个实现了Runnable接口的类，重写它的run()方法
2. 创建Thread对象，将第一个创建的Runnable类的对象作为参数传递过来
3. 通过Thread对象来启动线程

• 自定义Runnable

  public class MyRunnable implements Runnable {
      @Override
      public void run() {
          System.out.println(Thread.currentThread().getName() + "  *");
          try {
              Thread.sleep(1000);
          } catch (InterruptedException e) {
              e.printStackTrace();
          }
          System.out.println(Thread.currentThread().getName() + "  #");
      }
  }
  

• 测试代码

  public static void main(String[] args) {
      System.out.println(Thread.currentThread().getName());
      MyRunnable runnable = new MyRunnable();
      new Thread(runnable, "Thread-0 ").start();
      new Thread(runnable, "Thread-1 ").start();
      new Thread(runnable, "Thread-2 ").start();
  }
  

结果： 采用Labmda表达式改写上面代码

public static void main(String[] args) {
    System.out.println(Thread.currentThread().getName());
    Runnable runnable = () -> {
        System.out.println(Thread.currentThread().getName() + "  *");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(Thread.currentThread().getName() + "  #");
    };
    new Thread(runnable, "Thread-0 ").start();
    new Thread(runnable, "Thread-1 ").start();
    new Thread(runnable, "Thread-2 ").start();
}

使用Callable创建线程

• 自定义Callable

  public class MyCallable implements Callable {
      private String arg ;
      public MyCallable(String arg ) {
          this.arg = arg;
      }
      @Override
      public String call() { //线程执行体
          return arg.toUpperCase();
      }
  }
  

• 测试代码：

  public static void main(String[] args) throws Exception {
      // 使用Thread
      FutureTask task1 = new FutureTask(new MyCallable("helloworld"));
      new Thread(task1,"有返回值的线程").start();
      String res = task1.get();//FutureTask对象封装了Callable对象的call方法的返回值
      System.out.println(res);
      // 使用ExecutorService
      FutureTask task2 = new FutureTask(new MyCallable("Goodmoning"));
      ExecutorService pool = Executors.newCachedThreadPool();
      pool.submit(task2);
      System.out.println(task2.get());
      pool.shutdown();
      //
      FutureTask task3= new FutureTask(new MyCallable("NicetoMeetYou"));
      ExecutorService pool2 = Executors.newCachedThreadPool();
      pool2.execute(task3);
      System.out.println(task3.get());
      pool2.shutdown();
  }
  

结果：