并发编程(二) Lock用法

悠悠 2023-06-19 09:32 6阅读 0赞

**一、锁定类**

package com.zsx.demo.lock;
    
    import lombok.extern.log4j.Log4j2;
    
    import java.time.LocalDateTime;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;
    
    @Log4j2
    public class LockClass {
    
        private static final Lock lock = new ReentrantLock();
    
        public void print() {
            lock.lock();
            try {
                log.info("Current thread {} enters the print method, enter current time : {}", Thread.currentThread().getName(), LocalDateTime.now());
                TimeUnit.SECONDS.sleep(2);
                log.info("Current thread {} exits the print method, exit current time : {}", Thread.currentThread().getName(), LocalDateTime.now());
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public static void main(String[] args) {
            for (int i = 0; i < 5; i++) {
                new Thread(()->{
                    LockClass lockClass = new LockClass();
                    lockClass.print();
                    lockClass.print();
                }, String.format("t%d", i)).start();
            }
        }
    
    }

**1.运行结果**

14:06:19.471 [t0] INFO com.zsx.demo.lock.LockClass - Current thread t0 enters the print method, enter current time : 2019-12-05T14:06:19.466575
    14:06:21.476 [t0] INFO com.zsx.demo.lock.LockClass - Current thread t0 exits the print method, exit current time : 2019-12-05T14:06:21.476431400
    14:06:21.477 [t0] INFO com.zsx.demo.lock.LockClass - Current thread t0 enters the print method, enter current time : 2019-12-05T14:06:21.476431400
    14:06:23.478 [t0] INFO com.zsx.demo.lock.LockClass - Current thread t0 exits the print method, exit current time : 2019-12-05T14:06:23.478086200
    14:06:23.478 [t2] INFO com.zsx.demo.lock.LockClass - Current thread t2 enters the print method, enter current time : 2019-12-05T14:06:23.478889
    14:06:25.480 [t2] INFO com.zsx.demo.lock.LockClass - Current thread t2 exits the print method, exit current time : 2019-12-05T14:06:25.480727300
    14:06:25.481 [t2] INFO com.zsx.demo.lock.LockClass - Current thread t2 enters the print method, enter current time : 2019-12-05T14:06:25.481491600
    14:06:27.482 [t2] INFO com.zsx.demo.lock.LockClass - Current thread t2 exits the print method, exit current time : 2019-12-05T14:06:27.482367100
    14:06:27.483 [t1] INFO com.zsx.demo.lock.LockClass - Current thread t1 enters the print method, enter current time : 2019-12-05T14:06:27.482367100
    14:06:29.484 [t1] INFO com.zsx.demo.lock.LockClass - Current thread t1 exits the print method, exit current time : 2019-12-05T14:06:29.484020800
    14:06:29.484 [t1] INFO com.zsx.demo.lock.LockClass - Current thread t1 enters the print method, enter current time : 2019-12-05T14:06:29.484020800
    14:06:31.485 [t1] INFO com.zsx.demo.lock.LockClass - Current thread t1 exits the print method, exit current time : 2019-12-05T14:06:31.485670600
    14:06:31.486 [t3] INFO com.zsx.demo.lock.LockClass - Current thread t3 enters the print method, enter current time : 2019-12-05T14:06:31.486439
    14:06:33.487 [t3] INFO com.zsx.demo.lock.LockClass - Current thread t3 exits the print method, exit current time : 2019-12-05T14:06:33.487110600
    14:06:33.487 [t3] INFO com.zsx.demo.lock.LockClass - Current thread t3 enters the print method, enter current time : 2019-12-05T14:06:33.487110600
    14:06:35.487 [t3] INFO com.zsx.demo.lock.LockClass - Current thread t3 exits the print method, exit current time : 2019-12-05T14:06:35.487958200
    14:06:35.488 [t4] INFO com.zsx.demo.lock.LockClass - Current thread t4 enters the print method, enter current time : 2019-12-05T14:06:35.488767200
    14:06:37.489 [t4] INFO com.zsx.demo.lock.LockClass - Current thread t4 exits the print method, exit current time : 2019-12-05T14:06:37.489627300
    14:06:37.489 [t4] INFO com.zsx.demo.lock.LockClass - Current thread t4 enters the print method, enter current time : 2019-12-05T14:06:37.489627300
    14:06:39.491 [t4] INFO com.zsx.demo.lock.LockClass - Current thread t4 exits the print method, exit current time : 2019-12-05T14:06:39.491256800

**二、锁定对象**

package com.zsx.demo.lock;
    
    import lombok.extern.log4j.Log4j2;
    
    import java.time.LocalDateTime;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;
    
    @Log4j2
    public class LockObject {
    
        private final Lock lock = new ReentrantLock();
    
        public void print() {
            lock.lock();
            try {
                log.info("Current thread {} enters the print method, enter current time : {}", Thread.currentThread().getName(), LocalDateTime.now());
                TimeUnit.SECONDS.sleep(2);
                log.info("Current thread {} exits the print method, exit current time : {}", Thread.currentThread().getName(), LocalDateTime.now());
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public static void main(String[] args) {
            for (int i = 0; i < 5; i++) {
                new Thread(()->{
                    LockObject lockObject = new LockObject();
                    lockObject.print();
                    lockObject.print();
                }, String.format("t%d", i)).start();
            }
        }
    
    }

**2.运行结果**

14:12:00.627 [t2] INFO com.zsx.demo.lock.LockObject - Current thread t2 enters the print method, enter current time : 2019-12-05T14:12:00.621256700
    14:12:00.627 [t3] INFO com.zsx.demo.lock.LockObject - Current thread t3 enters the print method, enter current time : 2019-12-05T14:12:00.621256700
    14:12:00.627 [t1] INFO com.zsx.demo.lock.LockObject - Current thread t1 enters the print method, enter current time : 2019-12-05T14:12:00.621256700
    14:12:00.627 [t0] INFO com.zsx.demo.lock.LockObject - Current thread t0 enters the print method, enter current time : 2019-12-05T14:12:00.621256700
    14:12:00.626 [t4] INFO com.zsx.demo.lock.LockObject - Current thread t4 enters the print method, enter current time : 2019-12-05T14:12:00.621256700
    14:12:02.633 [t1] INFO com.zsx.demo.lock.LockObject - Current thread t1 exits the print method, exit current time : 2019-12-05T14:12:02.633123500
    14:12:02.633 [t3] INFO com.zsx.demo.lock.LockObject - Current thread t3 exits the print method, exit current time : 2019-12-05T14:12:02.633123500
    14:12:02.633 [t0] INFO com.zsx.demo.lock.LockObject - Current thread t0 exits the print method, exit current time : 2019-12-05T14:12:02.633123500
    14:12:02.633 [t2] INFO com.zsx.demo.lock.LockObject - Current thread t2 exits the print method, exit current time : 2019-12-05T14:12:02.633123500
    14:12:02.633 [t1] INFO com.zsx.demo.lock.LockObject - Current thread t1 enters the print method, enter current time : 2019-12-05T14:12:02.633897200
    14:12:02.633 [t3] INFO com.zsx.demo.lock.LockObject - Current thread t3 enters the print method, enter current time : 2019-12-05T14:12:02.633897200
    14:12:02.633 [t0] INFO com.zsx.demo.lock.LockObject - Current thread t0 enters the print method, enter current time : 2019-12-05T14:12:02.633897200
    14:12:02.633 [t2] INFO com.zsx.demo.lock.LockObject - Current thread t2 enters the print method, enter current time : 2019-12-05T14:12:02.633897200
    14:12:02.633 [t4] INFO com.zsx.demo.lock.LockObject - Current thread t4 exits the print method, exit current time : 2019-12-05T14:12:02.633123500
    14:12:02.634 [t4] INFO com.zsx.demo.lock.LockObject - Current thread t4 enters the print method, enter current time : 2019-12-05T14:12:02.634905600
    14:12:04.634 [t0] INFO com.zsx.demo.lock.LockObject - Current thread t0 exits the print method, exit current time : 2019-12-05T14:12:04.634749600
    14:12:04.634 [t1] INFO com.zsx.demo.lock.LockObject - Current thread t1 exits the print method, exit current time : 2019-12-05T14:12:04.634749600
    14:12:04.634 [t3] INFO com.zsx.demo.lock.LockObject - Current thread t3 exits the print method, exit current time : 2019-12-05T14:12:04.634749600
    14:12:04.634 [t2] INFO com.zsx.demo.lock.LockObject - Current thread t2 exits the print method, exit current time : 2019-12-05T14:12:04.634749600
    14:12:04.635 [t4] INFO com.zsx.demo.lock.LockObject - Current thread t4 exits the print method, exit current time : 2019-12-05T14:12:04.635527600