线程并发时，控制执行顺序

2017-04-05
package com.mengyanxin.utils.thread;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class TestThread {
    public static void main(String[] args) {
        final Print pt = new Print();
        new Thread(new Runnable() {
            public void run() {
                for (int i = 1; i <= 3; i++) {
                    pt.printA(i);
                }
            }
        },"A").start();
        new Thread(new Runnable() {
            public void run() {
                for (int i = 1; i <= 3; i++) {
                    pt.printB(i);
                }
            }
        },"B").start();
        new Thread(new Runnable() {
            public void run() {
                for (int i = 1; i <= 3; i++) {
                    pt.printC(i);
                    System.out.println("-----------------------------------");
                }
            }
        },"C").start();
    }
}
class Print {
    private int number = 1;
    private Lock lock = new ReentrantLock();
    private Condition conditionA = lock.newCondition();
    private Condition conditionB = lock.newCondition();
    private Condition conditionC = lock.newCondition();
    public void printA(int count){
        try {
            lock.lock();
            if (number != 1) {
                conditionA.await();
            }
            for (int i = 0; i < 1; i++) {
                System.out.println(Thread.currentThread().getName()+ "\t" + i + "\t" + "第" + count +"轮");
            }
            number = 2;
            conditionB.signal();
        } catch (Exception e) {
        }finally{
            lock.unlock();
        }
    }
    public void printB(int count){
        try {
            lock.lock();
            if (number != 2) {
                conditionB.await();
            }
            for (int i = 0; i < 1; i++) {
                System.out.println(Thread.currentThread().getName()+ "\t" + i + "\t" + "第" + count +"轮");
            }
            number = 3;
            conditionC.signal();
        } catch (Exception e) {
        }finally{
            lock.unlock();
        }
    }
    public void printC(int count){
        try {
            lock.lock();
            if (number != 3) {
                conditionC.await();
            }
            for (int i = 0; i < 1; i++) {
                System.out.println(Thread.currentThread().getName()+ "\t" + i + "\t" + "第" + count +"轮");
            }
            number = 1;
            conditionA.signal();
        } catch (Exception e) {
        }finally{
            lock.unlock();
        }
    }
}
输出结果：
A 0 第1轮
B 0 第1轮
C 0 第1轮
A 0 第2轮
B 0 第2轮
C 0 第2轮
A 0 第3轮
B 0 第3轮
C 0 第3轮