Java多线程synchronized同步方法详解

public class DirtyReadTest {
  public static void main(String[] args) {
    try {
      PublicVar publicVar = new PublicVar();
      ThreadA thread = new ThreadA(publicVar);
      thread.start();
      Thread.sleep(200);
      publicVar.getValue();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  static class ThreadA extends Thread {
    private PublicVar publicVar;

    public ThreadA(PublicVar publicVar) {
      this.publicVar = publicVar;
    }

    @Override
    public void run() {
      super.run();
      publicVar.setValue("B", "BB");
    }
  }

  static class PublicVar {
    public String username = "A";
    public String password = "AA";

    synchronized public void setValue(String username, String password) {
      try {
        this.username = username;
        Thread.sleep(1000);
        this.password = password;
        System.out.println("setValue method thread name = " + Thread.currentThread().getName() + "\tusername = " + username + "\tpassword = " + password);
      } catch (Exception e) {
        e.printStackTrace();
      }
    }

    // 因为 getValue 方法是非 synchronized 方法，所以造成了脏读
    public void getValue() {
      System.out.println("getValue method thread name = " + Thread.currentThread().getName() + "\tusername = " + username + "\tpassword = " + password);
    }
  }
}