## 多线程小题

``````package train20181010;

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

/* 编写一个程序，开启 3 个线程，
* 这三个线程的 ID 分别为 A、B、C，
* 每个线程将自己的 ID 在屏幕上打印 10 遍，
* 要求输出的结果必须按顺序显示。
* 如：ABCABCABC…… 依次递归
*/
public class TestABCAlternate {
public static void main(String[] args) {
@Override
public void run() {
for (int i = 1; i <= 10; i++) {
}
}
}, "A").start();
@Override
public void run() {
for (int i = 1; i <= 10; i++) {
}
}
}, "B").start();
@Override
public void run() {
for (int i = 1; i <= 10; i++) {
System.out.println("-----------------------------------");
}
}
}, "C").start();
}
}
class AlternateDemo{
private int number = 1; //当前正在执行线程的标记
private Lock lock = new ReentrantLock();
private Condition condition1 = lock.newCondition();
private Condition condition2 = lock.newCondition();
private Condition condition3 = lock.newCondition();
/**
* @param totalLoop : 循环第几轮
*/
public void loopA(int totalLoop){
lock.lock();
try {
//1. 判断
if(number != 1){
condition1.await();
}
//2. 打印
for (int i = 1; i <= 1; i++) {
}
//3、唤醒
number = 2;
condition2.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void loopB(int totalLoop){
lock.lock();
try {
//1. 判断
if(number != 2){
condition2.await();
}
//2. 打印
for (int i = 1; i <= 1; i++) {
}
//3. 唤醒
number = 3;
condition3.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void loopC(int totalLoop){
lock.lock();try {
//1. 判断
if(number != 3){
condition3.await();
}
//2. 打印
for (int i = 1; i <= 1; i++) {
}
//3. 唤醒
number = 1;
condition1.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
``````

0条评论