效果展示:
A     1
A     2
A     3
A     4
A     5
B     1
B     2
B     3
B     4
B     5
C     1
C     2
C     3
C     4
C     5代码实现:
package juc;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class AlternativePrint {
    private ReentrantLock lock = new ReentrantLock();
    private Condition conditionA = lock.newCondition();
    private Condition conditionB = lock.newCondition();
    private Condition conditionC = lock.newCondition();
    private int number = 1;
    public void loopA(){
        lock.lock();
        try {
            if (number != 1){
                conditionA.await();
            }
            for (int i = 1; i <= 5; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 2;
            conditionB.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    public void loopB(){
        lock.lock();
        try {
            if (number != 2){
                conditionB.await();
            }
            for (int i = 1; i <= 5; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 3;
            conditionC.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    public void loopC(){
        lock.lock();
        try {
            if (number != 3){
                conditionC.await();
            }
            for (int i = 1; i <= 5; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 1;
            conditionA.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            System.out.println("--------------------------------------------------");
            lock.unlock();
        }
    }
    public static void main(String[] args) {
        final AlternativePrint alternativePrint = new AlternativePrint();
        new Thread("A"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopA();
            }
        }.start();
        new Thread("B"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopB();
            }
        }.start();
        new Thread("C"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopC();
            }
        }.start();
    }
}
效果展示:
A     1
B     1
C     1
-----------------------------------------------------------------
A     1
B     1
C     1
-----------------------------------------------------------------代码实现:
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class AlternativePrint {
    private ReentrantLock lock = new ReentrantLock();
    private Condition conditionA = lock.newCondition();
    private Condition conditionB = lock.newCondition();
    private Condition conditionC = lock.newCondition();
    private int number = 1;
    public void loopA(){
        lock.lock();
        try {
            if (number != 1){
                conditionA.await();
            }
            for (int i = 1; i <= 1; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 2;
            conditionB.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    public void loopB(){
        lock.lock();
        try {
            if (number != 2){
                conditionB.await();
            }
            for (int i = 1; i <= 1; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 3;
            conditionC.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    public void loopC(){
        lock.lock();
        try {
            if (number != 3){
                conditionC.await();
            }
            for (int i = 1; i <= 1; i++){
                System.out.println(Thread.currentThread().getName() + "     " + i);
            }
            number = 1;
            conditionA.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            System.out.println("-----------------------------------------------");
            lock.unlock();
        }
    }
    public static void main(String[] args) {
        final AlternativePrint alternativePrint = new AlternativePrint();
        new Thread("A"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopA();
            }
        }.start();
        new Thread("B"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopB();
            }
        }.start();
        new Thread("C"){
            @Override
            public void run() {
                for (int i= 0; i < 20; i++)
                    alternativePrint.loopC();
            }
        }.start();
    }
}
原文:https://www.cnblogs.com/ch-forever/p/10293741.html