JUC练习代码-JUC版本实现生产者消费者问题

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原创最新推荐文章于 2026-06-17 13:19:40 发布 312 阅读 AI 写同款· GEO 优化 ›

个人学习JUC代码笔记总集个人学习的时候对JUC做的笔记，包括所有代码，学习视频是尚硅谷周阳老师的JUC，需要有一定的基础才能看懂，这是个人笔记，不一定适用于所有人，谢谢！立即下载

public class JUCTest02 {
    public static void main(String[] args) throws InterruptedException {
        Data2 data = new Data2();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();

    }
}

//判断是否等待，业务，干完活通知
class Data2 {
    private int number = 0;
    Lock lock = new ReentrantLock();
    Condition condition = lock.newCondition();

    public void increment() throws InterruptedException {
        lock.lock();
        try {

            while (number > 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition.await();
            }
            number++;

            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了+1" + ";number=" + number);
            condition.signalAll();
        } catch (Exception e) {
            e.printStackTrace();

        } finally {
            lock.unlock();
        }


    }

    public void decrement() throws InterruptedException {
        lock.lock();
        try {

            while (number <= 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition.await();
            }
            number--;
            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了-1" + ";number=" + number);
            condition.signalAll();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }


    }
}

编写代码时注意顺序，首先是lock.lock()，然后try 里面包括业务逻辑，最后finally lock.unlock()
Condition也是JUC包下接口，可以通过lock.newCondition()进行实例化。
Condition中await，signal ，signalAll方法，对应Object的wait，notify，notifyAll方法。

上述代码样例打印的部分结果如下所示

A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
Await
B执行了-1;number=0
Bwait

虽然满足0，1输出，但是怎么保证ABCD也是按照顺序打印呢？

其实只要创建多个condition对象，就可以精确等待和唤醒了。如下图代码所示：

public class JUCTest02 {
    public static void main(String[] args) throws InterruptedException {
        Data2 data = new Data2();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.increment1();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.decrement2();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.increment3();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();
        new Thread(() -> {
            for (int i = 0; i < 20; i++) {
                try {
                    data.decrement4();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();

    }
}

//判断是否等待，业务，干完活通知
class Data2 {
    private int number = 0;
    Lock lock = new ReentrantLock();
    Condition condition1 = lock.newCondition();
    Condition condition2 = lock.newCondition();
    Condition condition3 = lock.newCondition();
    Condition condition4 = lock.newCondition();

    public void increment1() throws InterruptedException {
        lock.lock();
        try {

            while (number > 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition1.await();
            }
            number++;

            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了+1" + ";number=" + number);
            condition2.signal();
        } catch (Exception e) {
            e.printStackTrace();

        } finally {
            lock.unlock();
        }


    }

    public void decrement2() throws InterruptedException {
        lock.lock();
        try {

            while (number <= 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition2.await();
            }
            number--;
            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了-1" + ";number=" + number);
            condition3.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }


    }

    public void increment3() throws InterruptedException {
        lock.lock();
        try {

            while (number > 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition3.await();
            }
            number++;

            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了+1" + ";number=" + number);
            condition4.signal();
        } catch (Exception e) {
            e.printStackTrace();

        } finally {
            lock.unlock();
        }


    }

    public void decrement4() throws InterruptedException {
        lock.lock();
        try {

            while (number <= 0) {
                //等待
                System.out.println(Thread.currentThread().getName() + "wait");
                condition4.await();
            }
            number--;
            //通知其他线程，我+1完毕了
            System.out.println(Thread.currentThread().getName() + "执行了-1" + ";number=" + number);
            condition1.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }


    }

部分打印结果，如下所示：

A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait
A执行了+1;number=1
Await
B执行了-1;number=0
Bwait
C执行了+1;number=1
Cwait
D执行了-1;number=0
Dwait

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