两个线程交替打印奇数和偶数

超、凢脫俗 2021-06-22 15:38 372阅读 0赞

实现思路是使用锁来控制不同线程的执行。下面有两种实现：

1、使用对象监视器：

public class OddEvenPrinter {
    
        private final Object monitor = new Object();
        private final int limit;
        private volatile int count;
    
        public OddEvenPrinter(int limit, int initCount) {
            this.limit = limit;
            this.count = initCount;
        }
    
        public void print() {
            synchronized (monitor) {
                while (count < limit) {
                    try {
                        System.out.println(String.format("线程[%s]打印数字:%d", Thread.currentThread().getName(), ++count));
                        monitor.notifyAll();
                        monitor.wait();
                    } catch (InterruptedException e) {
                        //ignore
                    }
                }
            }
        }
    
        public static void main(String[] args) throws Exception {
            OddEvenPrinter printer = new OddEvenPrinter(10, 0);
            Thread thread1 = new Thread(printer::print, "thread-1");
            Thread thread2 = new Thread(printer::print, "thread-2");
            thread1.start();
            thread2.start();
            Thread.sleep(Integer.MAX_VALUE);
        }
    }

2、使用jdk的并发库：

public class OddEvenPrinterEx {
    
        private final ReentrantLock lock = new ReentrantLock();
        private final Condition condition = lock.newCondition();
    
        private final int limit;
        private volatile int count;
    
        public OddEvenPrinterEx(int limit, int initCount) {
            this.limit = limit;
            this.count = initCount;
        }
    
        public void print()  {
            lock.lock();
            try {
               while (count < limit){
                   System.out.println(String.format("线程[%s]打印数字:%d", Thread.currentThread().getName(), ++count));
                   condition.signalAll();
                   try {
                       condition.await();
                   } catch (InterruptedException e) {
                       //ignore
                   }
               }
            } finally {
                lock.unlock();
            }
        }
    
        public static void main(String[] args) throws Exception {
            OddEvenPrinterEx printer = new OddEvenPrinterEx(10, 0);
            Thread thread1 = new Thread(printer::print, "thread-1");
            Thread thread2 = new Thread(printer::print, "thread-2");
            thread1.start();
            thread2.start();
            Thread.sleep(Integer.MAX_VALUE);
        }
    }