LockSupport

LockSupport是一个线程工具类，所有的方法都是静态方法，可以让线程在任意位置阻塞，也可以在任意位置唤醒。它的内部其实两类主要的方法：park（停车阻塞线程）和unpark（启动唤醒线程）。

public class Test{
  static Thread t1 = null , t2 = null;
  public static void main(){
    char[] aI = "1234567".toCharArray();
    char[] aC = "ABCDEFG".toCharArray();

    t1 = new Thread(()->{
      for(char c:aI){
         System.out.print(c);
         LockSupport.unpark(t2);      //唤醒t2
         LockSupport.park();          //阻塞
       }
    },"t1").start();

    t2 = new Thread(()->{
          for(char c : aC){
              LockSupport.park();
              System.out.print(c);
              LockSupport.unpark(t1);
          }
    },"t2").start();
  }
}

wait() & notify()

利用synchronized 锁定

public class Test{
 
  final Object o = new Object();
  public static void main(){
    char[] aI = "1234567".toCharArray();
    char[] aC = "ABCDEFG".toCharArray();

    t1 = new Thread(()->{
      sychronized(o){
        for(char c : aI) {
                    System.out.print(c);
                    try {
                        o.notify();
                        o.wait(); //让出锁
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                o.notify(); //必须，否则无法停止程序
      }
    },"t1").start();

    new Thread(()->{
            synchronized (o) {
                for(char c : aC) {
                    System.out.print(c);
                    try {
                        o.notify();
                        o.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                o.notify();
            }
        }, "t2").start();
  }
}