java 两个线程按顺序输出字符

方法一：

public class threadDemo {
    public static void main(String[] args) {
        final Object o=new Object();
         final char[] nums="1234567".toCharArray();
        final char[]  chars="ABCDEFG".toCharArray();
         new Thread(new Runnable() {
             @SneakyThrows
             @Override
             public void run() {
                 synchronized (o){
                     for(char num:nums){
                         System.out.println(num);
                         o.notify();
                         o.wait();
                     }
                     o.notify();
                 }
             }
         }).start();
        new Thread(new Runnable() {
            @SneakyThrows
            @Override
            public void run() {
                synchronized (o){
                    for(char ch:chars){
                        System.out.println(ch);
                        o.notify();
                        o.wait();
                    }
                    o.notify();
                }
            }
        }).start();
    }
}

方法二：

public class threadDemo {
    static Thread t1=null,t2=null;
    public static void main(String[] args) {

         final char[] nums="1234567".toCharArray();
        final char[]  chars="ABCDEFG".toCharArray();
         t1=new Thread(new Runnable() {
             @Override
             public void run() {
                 for(char num:nums){
                     System.out.println(num);
                     LockSupport.unpark(t2);
                     LockSupport.park();
                 }
             }
         });
        t2=new Thread(new Runnable() {
            @Override
            public void run() {
                for(char num:chars){
                    LockSupport.park();//挂起
                    System.out.println(num);
                    LockSupport.unpark(t1);//叫醒
                }
            }
        });
        t1.start();
        t2.start();
    }
}

方法三：

public class threadDemo {

    public static void main(String[] args) {

         final char[] nums="1234567".toCharArray();
        final char[]  chars="ABCDEFG".toCharArray();
        final Lock reentrantLock = new ReentrantLock();
        final Condition condition = reentrantLock.newCondition();
        new Thread(new Runnable() {
             @Override
             public void run() {
                 reentrantLock.lock();//相当synchronized
                 for(char num:nums){
                     System.out.println(num);
                     condition.signal();//相当于notify
                     try {
                         condition.await();
                     } catch (InterruptedException e) {
                         e.printStackTrace();
                     }
                 }
                 condition.signal();
             }
         }).start();
        new Thread(new Runnable() {
            @Override
            public void run() {
                reentrantLock.lock();
                for(char num:chars){
                    System.out.println(num);
                    try {
                        condition.signal();
                        condition.await();

                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                condition.signal();
            }
        }).start();
    }
}