逻辑：当线程1 执行完之后 通知线程2 再通知3 循序
    用了ReentrantLock锁来完成，创建多个Condition

    1. package com.daijunyi.lock;
    3. import java.util.concurrent.locks.Condition;
    4. import java.util.concurrent.locks.ReentrantLock;
    6. public class PrintTest {
    8.     private int flag = 0; //0表示 c1 1表示 c2 2表示c3
    10.     private ReentrantLock reentrantLock  = new ReentrantLock();
    12.     private Condition c1 = reentrantLock.newCondition();
    13.     private Condition c2 = reentrantLock.newCondition();
    14.     private Condition c3 = reentrantLock.newCondition();
    16.     private void print1() throws InterruptedException {
    17.         reentrantLock.lock();
    18.         try {
    19.             while (flag != 0){
    20.                 c1.await();
    21.             }
    22.             System.out.println(Thread.currentThread().getName()+"print1打印");
    23.             flag = 1;
    24.             c2.signal();
    25.         }finally {
    26.             reentrantLock.unlock();
    27.         }
    28.     }
    30.     private void print2() throws InterruptedException {
    31.         reentrantLock.lock();
    32.         try {
    33.             while (flag != 1){
    34.                 c2.await();
    35.             }
    36.             System.out.println(Thread.currentThread().getName()+"print2打印");
    37.             flag = 2;
    38.             c3.signal();
    39.         }finally {
    40.             reentrantLock.unlock();
    41.         }
    42.     }
    44.     private void print3() throws InterruptedException {
    45.         reentrantLock.lock();
    46.         try {
    47.             while (flag != 2){
    48.                 c3.await();
    49.             }
    50.             System.out.println(Thread.currentThread().getName()+"print3打印");
    51.             flag = 0;
    52.             c1.signal();
    53.         }finally {
    54.             reentrantLock.unlock();
    55.         }
    56.     }
    58.     public static void main(String[] args) {
    59.         PrintTest printTest = new PrintTest();
    60.         new Thread(()->{
    61.             for (int i=0;i<10;i++){
    62.                 try {
    63.                     printTest.print1();
    64.                 } catch (InterruptedException e) {
    65.                     e.printStackTrace();
    66.                 }
    67.             }
    69.         },"线程1").start();
    71.         new Thread(()->{
    72.             for (int i=0;i<10;i++) {
    73.                 try {
    74.                     printTest.print2();
    75.                 } catch (InterruptedException e) {
    76.                     e.printStackTrace();
    77.                 }
    78.             }
    79.         },"线程2").start();
    81.         new Thread(()->{
    82.             for (int i=0;i<10;i++) {
    83.                 try {
    84.                     printTest.print3();
    85.                 } catch (InterruptedException e) {
    86.                     e.printStackTrace();
    87.                 }
    88.             }
    89.         },"线程3").start();
    90.     }
    91. }