多线程通讯之共享内存二（可重用锁）

Posted 2020-10-14 纳木错星空

1.三个线程交替各打印15次，如此循环10次。

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;


public class ReentrantLockAndThreadTask {
    //三个任务依次执行15次，共执行10轮
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        final Transaction tran = new Transaction();
        
        new Thread(new Runnable() {
            
            @Override
            public void run() {
                // TODO Auto-generated method stub
                for (int i = 0 ; i < 15; i ++){
                    tran.sub2(i);
                }
            }
        }).start();
        new Thread(new Runnable() {
                    
            @Override
            public void run() {
                // TODO Auto-generated method stub
                for (int i = 0 ; i < 15; i ++){
                    tran.sub3(i);
                }
            }
        }).start();
        for (int i = 0 ; i < 15; i ++){
            tran.sub1(i);
        }
    }

}
class Transaction{
    private int turn = 1;
    ReentrantLock tranLock = new ReentrantLock(true);
    Condition condition1 = tranLock.newCondition();
    Condition condition2 = tranLock.newCondition();
    Condition condition3 = tranLock.newCondition();
    public void sub1(int j){
        tranLock.lock();
        try {
            while (turn != 1){
                //如果不是第一个线程的轮次就等待
                condition1.await();
                System.out.println("111");
            }
            for (int i = 0 ; i < 15; i ++){
                System.out.println(Thread.currentThread().getName()+"正在执行第："+j+"次序列号是:"+i);;
            }
            turn = 2;
            condition2.signal();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            tranLock.unlock();
        }
    }
    public void sub2(int j){
        boolean ishold = tranLock.isHeldByCurrentThread();
        int num = tranLock.getHoldCount();
        tranLock.lock();
        int num1 = tranLock.getHoldCount();
        boolean ishold1 = tranLock.isHeldByCurrentThread();
        try {
            while (turn != 2){
                //如果不是第一个线程的轮次就等待
                condition2.await();
                System.out.println("222");
            }
            for (int i = 0 ; i < 15; i ++){
                System.out.println(Thread.currentThread().getName()+"正在执行第："+j+"次序列号是:"+i);;
            }
            turn = 3;
            condition3.signal();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            tranLock.unlock();
        }
    }
    public void sub3(int j){
        tranLock.lock();
        try {
            while (turn != 3){
                //如果不是第一个线程的轮次就等待
                condition3.await();
                System.out.println("333");
            }
            for (int i = 0 ; i < 15; i ++){
                System.out.println(Thread.currentThread().getName()+"正在执行第："+j+"次序列号是:"+i);;
            }
            turn = 1;
            condition1.signal();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            tranLock.unlock();
        }
    }
}