一、需求
- A、B、C 三个线程，循环10次，打印出自己的名称，ABC,ABC,ABC...
- A、B、C 三个线程，循环10次，打印出自己的名称，A一次，B三次，C五次，ABBBCCCCC，ABBBCCCCC
1.1、循环打印ABC
package com.example.demo.juc;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * @author DUCHONG * @since 2019-01-21 10:46 **/public class ABC { public static void main(String[] args) { PrintDemo pd=new PrintDemo(); //A 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printA(i); } } },"A").start(); //B 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printB(i); } } },"B").start(); //C 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printC(i); } } },"C").start(); }}class PrintDemo{ Lock lock =new ReentrantLock(); private Condition conditionA=lock.newCondition(); private Condition conditionB=lock.newCondition(); private Condition conditionC=lock.newCondition(); //哪个线程等待与否的标记,flag的值： // 1 线程A打印，否则等待，同时将标记设置为2，唤醒线程B // 2 线程B打印，否则等待，同时将标记设置为3，唤醒线程C // 3 线程C打印，否则等待，同时将标记设置为1，唤醒线程A 外层一次循环结束。 private Integer flag=1; //打印A public void printA(int loop){ try{ lock.lock(); if(flag!=1){ conditionA.await(); } for (int i=1;i<=1;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=2; conditionB.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } } //打印B public void printB(int loop){ try{ lock.lock(); if(flag!=2){ conditionB.await(); } for (int i=1;i<=1;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=3; conditionC.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } } //打印C public void printC(int loop){ try{ lock.lock(); if(flag!=3){ conditionC.await(); } for (int i=1;i<=1;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=1; conditionA.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } }} 结果：
1.2、循环打印ABBBCCCC
package com.example.demo.juc;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * @author DUCHONG * @since 2019-01-21 14:15 **/public class ABBB { public static void main(String[] args) { PrintABBBDemo pd=new PrintABBBDemo(); //A 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printA(i); } } },"A").start(); //B 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printB(i); } } },"B").start(); //C 线程 new Thread(new Runnable() { @Override public void run() { for (int i = 1; i <=10 ; i++) { pd.printC(i); } } },"C").start(); }}class PrintABBBDemo{ Lock lock =new ReentrantLock(); private Condition conditionA=lock.newCondition(); private Condition conditionB=lock.newCondition(); private Condition conditionC=lock.newCondition(); //哪个线程等待与否的标记,flag的值： // 1 线程A打印，否则等待，同时将标记设置为2，唤醒线程B // 2 线程B打印，否则等待，同时将标记设置为3，唤醒线程C // 3 线程C打印，否则等待，同时将标记设置为1，唤醒线程A 外层一次循环结束。 private Integer flag=1; //打印A public void printA(int loop){ try{ lock.lock(); if(flag!=1){ conditionA.await(); } for (int i=1;i<=1;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=2; conditionB.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } } //打印B public void printB(int loop){ try{ lock.lock(); if(flag!=2){ conditionB.await(); } for (int i=1;i<=3;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=3; conditionC.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } } //打印C public void printC(int loop){ try{ lock.lock(); if(flag!=3){ conditionC.await(); } for (int i=1;i<=5;i++) { System.out.println(Thread.currentThread().getName() + "---" + loop); } flag=1; conditionA.signal(); } catch(Exception e){ e.printStackTrace(); } finally { lock.unlock(); } }} 结果：
