《SpringBoot2.0 实战》系列-集成redisson实现分布式锁

以你之姓@ 2023-06-13 06:13 33阅读 0赞

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### 前言 ###

最近面试总是会被问到有没有用过分布式锁、redis锁，由于平时很少接触到，所以只能很无奈的回答“没有”。回来之后就恶补了一下，本文主要做下记录，通过SpringBoot整合redisson来实现分布式锁，并结合demo测试结果。

首先看下大佬总结的图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0hYTkxZVw_size_16_color_FFFFFF_t_70][] 来源： [https://www.cnblogs.com/qdhxhz/p/11046905.html][https_www.cnblogs.com_qdhxhz_p_11046905.html]

### 正文 ###

**增加依赖**

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>
    
    <dependency>
        <groupId>org.redisson</groupId>
        <artifactId>redisson-spring-boot-starter</artifactId>
        <version>3.10.6</version>
    </dependency>

**配置 信息**

spring:
      # redis
      redis:
        host: 47.103.5.190
        port: 6379
        jedis:
          pool:
            # 连接池最大连接数（使用负值表示没有限制）
            max-active: 100
            # 连接池中的最小空闲连接
            max-idle: 10
            # 连接池最大阻塞等待时间（使用负值表示没有限制）
            max-wait: -1
          # 连接超时时间（毫秒）
          timeout: 5000
          #默认是索引为0的数据库
          database: 0

**配置类**

/**
     * redisson 配置，下面是单节点配置：
     *
     * @author gourd
     */
    @Configuration
    public class RedissonConfig {
        @Value("${spring.redis.host}")
        private String host;
        @Value("${spring.redis.port}")
        private String port;
        @Value("${spring.redis.password:}")
        private String password;
    
        @Bean
        public RedissonClient redissonClient() {
            Config config = new Config();
            //单节点
            config.useSingleServer().setAddress("redis://" + host + ":" + port);
            if (StringUtils.isEmpty(password)) {
                config.useSingleServer().setPassword(null);
            } else {
                config.useSingleServer().setPassword(password);
            }
            //添加主从配置
    // config.useMasterSlaveServers().setMasterAddress("").setPassword("").addSlaveAddress(new String[]{"",""});
            // 集群模式配置 setScanInterval()扫描间隔时间，单位是毫秒, //可以用"rediss://"来启用SSL连接
    // config.useClusterServers().setScanInterval(2000).addNodeAddress("redis://127.0.0.1:7000", "redis://127.0.0.1:7001").addNodeAddress("redis://127.0.0.1:7002");
            return Redisson.create(config);
        }
    }

**Redisson工具类**

/**
     * redis分布式锁帮助类
     *
     * @author gourd
     *
     */
    public class RedisLockUtil {
    
        private static DistributedLocker distributedLocker = SpringContextHolder.getBean("distributedLocker",DistributedLocker.class);
    
        /**
         * 加锁
         * @param lockKey
         * @return
         */
        public static RLock lock(String lockKey) {
            return distributedLocker.lock(lockKey);
        }
    
        /**
         * 释放锁
         * @param lockKey
         */
        public static void unlock(String lockKey) {
            distributedLocker.unlock(lockKey);
        }
        
        /**
         * 释放锁
         * @param lock
         */
        public static void unlock(RLock lock) {
            distributedLocker.unlock(lock);
        }
    
        /**
         * 带超时的锁
         * @param lockKey
         * @param timeout 超时时间   单位：秒
         */
        public static RLock lock(String lockKey, int timeout) {
            return distributedLocker.lock(lockKey, timeout);
        }
        
        /**
         * 带超时的锁
         * @param lockKey
         * @param unit 时间单位
         * @param timeout 超时时间
         */
        public static RLock lock(String lockKey, int timeout,TimeUnit unit ) {
            return distributedLocker.lock(lockKey, unit, timeout);
        }
        
        /**
         * 尝试获取锁
         * @param lockKey
         * @param waitTime 最多等待时间
         * @param leaseTime 上锁后自动释放锁时间
         * @return
         */
        public static boolean tryLock(String lockKey, int waitTime, int leaseTime) {
            return distributedLocker.tryLock(lockKey, TimeUnit.SECONDS, waitTime, leaseTime);
        }
        
        /**
         * 尝试获取锁
         * @param lockKey
         * @param unit 时间单位
         * @param waitTime 最多等待时间
         * @param leaseTime 上锁后自动释放锁时间
         * @return
         */
        public static boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime) {
            return distributedLocker.tryLock(lockKey, unit, waitTime, leaseTime);
        }
    
        /**
         * 获取计数器
         *
         * @param name
         * @return
         */
        public static RCountDownLatch getCountDownLatch(String name){
            return distributedLocker.getCountDownLatch(name);
        }
    
        /**
         * 获取信号量
         *
         * @param name
         * @return
         */
        public static RSemaphore getSemaphore(String name){
            return distributedLocker.getSemaphore(name);
        }
    }

**底层封装**

/**
     * @author gourd
     */
    public interface DistributedLocker {
    
        RLock lock(String lockKey);
    
        RLock lock(String lockKey, int timeout);
    
        RLock lock(String lockKey, TimeUnit unit, int timeout);
    
        boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime);
    
        void unlock(String lockKey);
    
        void unlock(RLock lock);
    }
    
    /**
     * @author gourd
     */
    @Component
    public class RedisDistributedLocker implements DistributedLocker {
    
        @Autowired
        private RedissonClient redissonClient;
    
        @Override
        public RLock lock(String lockKey) {
            RLock lock = redissonClient.getLock(lockKey);
            lock.lock();
            return lock;
        }
    
        @Override
        public RLock lock(String lockKey, int leaseTime) {
            RLock lock = redissonClient.getLock(lockKey);
            lock.lock(leaseTime, TimeUnit.SECONDS);
            return lock;
        }
        
        @Override
        public RLock lock(String lockKey, TimeUnit unit ,int timeout) {
            RLock lock = redissonClient.getLock(lockKey);
            lock.lock(timeout, unit);
            return lock;
        }
        
        @Override
        public boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime) {
            RLock lock = redissonClient.getLock(lockKey);
            try {
                return lock.tryLock(waitTime, leaseTime, unit);
            } catch (InterruptedException e) {
                return false;
            }
        }
        
        @Override
        public void unlock(String lockKey) {
            RLock lock = redissonClient.getLock(lockKey);
            lock.unlock();
        }
        
        @Override
        public void unlock(RLock lock) {
            lock.unlock();
        }
    }

### 测试 ###

模拟并发测试

/**
     * redis分布式锁控制器
     * @author gourd
     * @since 2019-07-30
     */
    @RestController
    @Api(tags = "redisson", description = "redis分布式锁控制器" )
    @RequestMapping("/redisson" )
    @Slf4j
    public class RedissonLockController {
    
        /**
         * 锁测试共享变量
         */
        private Integer lockCount = 10;
    
        /**
         * 无锁测试共享变量
         */
        private Integer count = 10;
    
        /**
         * 模拟线程数
         */
        private static int threadNum = 10;
    
        /**
         * 模拟并发测试加锁和不加锁
         * @return
         */
        @GetMapping("/test")
        @ApiOperation(value = "模拟并发测试加锁和不加锁")
        public void lock(){
            // 计数器
            final CountDownLatch countDownLatch = new CountDownLatch(1);
            for (int i = 0; i < threadNum; i ++) {
                MyRunnable myRunnable = new MyRunnable(countDownLatch);
                Thread myThread = new Thread(myRunnable);
                myThread.start();
            }
            // 释放所有线程
            countDownLatch.countDown();
        }
    
        /**
         * 加锁测试
         */
        private void testLockCount() {
            String lockKey = "lock-test";
            try {
                // 加锁，设置超时时间2s
                RedisLockUtil.lock(lockKey,2, TimeUnit.SECONDS);
                lockCount--;
                log.info("lockCount值："+lockCount);
            }catch (Exception e){
                log.error(e.getMessage(),e);
            }finally {
                // 释放锁
                RedisLockUtil.unlock(lockKey);
            }
        }
    
        /**
         * 无锁测试
         */
        private void testCount() {
            count--;
            log.info("count值："+count);
        }
    
    
        public class MyRunnable implements Runnable {
            /**
             * 计数器
             */
            final CountDownLatch countDownLatch;
    
            public MyRunnable(CountDownLatch countDownLatch) {
                this.countDownLatch = countDownLatch;
            }
    
            @Override
            public void run() {
                try {
                    // 阻塞当前线程，直到计时器的值为0
                    countDownLatch.await();
                } catch (InterruptedException e) {
                    log.error(e.getMessage(),e);
                }
                // 无锁操作
                testCount();
                // 加锁操作
                testLockCount();
            }
    
        }
    
    }

![20191230143338440.jpeg][]

调用接口后打印值：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0hYTkxZVw_size_16_color_FFFFFF_t_70 1][] 测试结果

根据打印结果可以明显看到，未加锁的count--后值是乱序的，而加锁后的结果和我们预期的一样。

由于条件问题没办法测试分布式的并发。只能模拟单服务的这种并发，但是原理是一样，希望对大家有帮助。如有错误之处，欢迎指正。

====================================================

代码均已上传至本人的开源项目

![20191230131831499.jpeg][]

spring-cloud-plus：[https://blog.csdn.net/HXNLYW/article/details/104635673][https_blog.csdn.net_HXNLYW_article_details_104635673]

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[https_www.cnblogs.com_qdhxhz_p_11046905.html]: https://www.cnblogs.com/qdhxhz/p/11046905.html
[20191230143338440.jpeg]: https://img-blog.csdnimg.cn/20191230143338440.jpeg
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0hYTkxZVw_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191114162857464.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0hYTkxZVw==,size_16,color_FFFFFF,t_70
[20191230131831499.jpeg]: https://img-blog.csdnimg.cn/20191230131831499.jpeg
[https_blog.csdn.net_HXNLYW_article_details_104635673]: https://blog.csdn.net/HXNLYW/article/details/104635673