redis和redisson实现分布式锁

谁借莪１个温暖的怀抱￠ 2022-12-27 09:30 186阅读 0赞

### 文章目录 ###

*  redis 实现分布式锁
 *   *  一、redis原生方式实现分布式锁
     *  二、Redisson实现分布式锁
     *   *  1.导入jar包
         *  2.设置连接配置
         *  3.编写代码实现分布式锁
     *  三、注解aop的方式加Redisson实现分布式锁（推荐）

# redis 实现分布式锁 #

介绍三种方式实现分布式锁：

1.  Redis原生方式实现分布式锁
2.  Redisson实现分布式锁
3.  注解aop的方式加Redisson实现分布式锁（推荐）

## 一、redis原生方式实现分布式锁 ##

Redis 单线程

SETNX (set if not exists)

setnx key value 若key存在则添加失败，若key不存在才会添加存在

redisTempalte.setIfAbsetn(key,value,time) 设置 key 和 value 和 超时时间

try {
        // todo 业务
        
        } finally {
            // get 值，若 value 与 设置的value相等 则 删除key
            
        }

简单的实现分布式锁：

// 这里使用到了 springboot集成Redis 用到了springboot的 StringRedisTemplate
    @GetMapping("/transaction")
        public String transaction() { 
            // 锁的键值
            String lockKey = "orderLock";
            // 设置客户端id
            String clientId = UUID.randomUUID().toString();
            try { 
                // 设置锁 如果redis中已经存在 lockKey 则会添加失败
                Boolean result = stringRedisTemplate.opsForValue().setIfAbsent(lockKey, clientId, 30, TimeUnit.SECONDS);
    
                if (result == null || !result) { 
                    return "error";
                }
                String stock = stringRedisTemplate.opsForValue().get("stock");
                if (StrUtil.isEmpty(stock)) { 
                    return ">>>>>>>> 数据异常请稍后重试";
                }
                int number = Integer.parseInt(stock);
                if (number > 0) { 
                    Long lastNumber = stringRedisTemplate.opsForValue().decrement("stock");
                    System.out.println(">>>>>>>>>>> 扣除库存成功，剩余：" + lastNumber);
                } else { 
                    System.out.println(">>>>>>>>>>> 扣除库存失败，库存不足");
                }
            } finally { 
                // 如果客户端id相等
                if (clientId.equals(stringRedisTemplate.opsForValue().get(lockKey))) { 
                    stringRedisTemplate.delete(lockKey);
                }
            }
            return "success";
        }

## 二、Redisson实现分布式锁 ##

### 1.导入jar包 ###

<dependency>
         <groupId>org.redisson</groupId>
         <artifactId>redisson</artifactId>
         <version>3.12.0</version>
    </dependency>

### 2.设置连接配置 ###

@Getter
    @Setter
    @ConfigurationProperties(prefix="redisson")
    public class RedissonProperties { 
    
        private int timeout = 3000;
    
        private String address;
    
        private String password;
    
        private int connectionPoolSize = 64;
    
        private int connectionMinimumIdleSize=10;
    
        private int slaveConnectionPoolSize = 250;
    
        private int masterConnectionPoolSize = 250;
    
        private String[] sentinelAddresses;
    
        private String masterName;
    
    }

// 自动装配

@Configuration
    @ConditionalOnClass(Config.class)
    @EnableConfigurationProperties(RedissonProperties.class)
    public class RedissonAutoConfiguration { 
    
    
        @Autowired
        private RedissonProperties redssionProperties;
    
    	// import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
    // @Autowired
    // private RedisProperties redisProperties;
    
        /** * 哨兵模式自动装配 * # 哨兵模式 * #redisson: * # master-name: mymaster * # password: * # sentinel-addresses: 10.47.91.83:26379,10.47.91.83:26380,10.47.91.83:26381 * @return */
    // @Bean
    // @ConditionalOnProperty(name="redisson.master-name")
    // RedissonClient redissonSentinel() { 
    // Config config = new Config();
    // SentinelServersConfig serverConfig = config.useSentinelServers().addSentinelAddress(redssionProperties.getSentinelAddresses())
    // .setMasterName(redssionProperties.getMasterName())
    // .setTimeout(redssionProperties.getTimeout())
    // .setMasterConnectionPoolSize(redssionProperties.getMasterConnectionPoolSize())
    // .setSlaveConnectionPoolSize(redssionProperties.getSlaveConnectionPoolSize());
    //
    // if(StrUtil.isNotBlank(redssionProperties.getPassword())) { 
    // serverConfig.setPassword(redssionProperties.getPassword());
    // }
    // return Redisson.create(config);
    // }
    
        /** * 单机模式自动装配 * @return */
        @Bean
        @ConditionalOnProperty(name="redisson.address")
        RedissonClient redissonClient() { 
            Config config = new Config();
            SingleServerConfig serverConfig = config.useSingleServer()
                    .setAddress(redssionProperties.getAddress())
                    .setTimeout(redssionProperties.getTimeout())
                    .setDatabase(0)
                    .setConnectionPoolSize(redssionProperties.getConnectionPoolSize())
                    .setConnectionMinimumIdleSize(redssionProperties.getConnectionMinimumIdleSize());
            if(StrUtil.isNotBlank(redssionProperties.getPassword())) { 
                serverConfig.setPassword(redssionProperties.getPassword());
            }
    
            return Redisson.create(config);
        }
    }
    
    /** * redis集群下的配置 cluster * @return */
    // @Bean
    // public RedissonClient redisson() { 
    // //redisson版本是3.5，集群的ip前面要加上“redis://”，不然会报错，3.2版本可不加
    // List<String> clusterNodes = new ArrayList<>();
    // for (int i = 0; i < redisProperties.getCluster().getNodes().size(); i++) { 
    // clusterNodes.add("redis://" + redisProperties.getCluster().getNodes().get(i));
    // }
    // Config config = new Config();
    // // 采用集群模式
    // ClusterServersConfig clusterServersConfig = config.useClusterServers()
    // .addNodeAddress(clusterNodes.toArray(new String[clusterNodes.size()]));
    // //设置密码 注意这里集群的 redis 密码都必须一致
    // clusterServersConfig.setPassword(redisProperties.getPassword());
    // return Redisson.create(config);
    // }

yaml中的配置文件

# 哨兵模式
    #redisson:
    # master-name: mymaster
    # password:
    # sentinel-addresses: 10.47.91.83:26379,10.47.91.83:26380,10.47.91.83:26381
    
    
    # redis单机模式
    redisson:
      address: redis://81.69.43.66:6379
      password: root

### 3.编写代码实现分布式锁 ###

// 实现分布式锁

@GetMapping("/redisson")
        public String redisson() { 
            String lockKey = "orderLock";
            // 获取锁
            RLock lock = redissonClient.getLock(lockKey);
            try { 
                // 加锁
                lock.lock();
    
                String stock = stringRedisTemplate.opsForValue().get("stock");
                if (StrUtil.isEmpty(stock)) { 
                    return ">>>>>>>> 数据异常请稍后重试";
                }
                int number = Integer.parseInt(stock);
                if (number > 0) { 
                    Long lastNumber = stringRedisTemplate.opsForValue().decrement("stock");
                    System.out.println(">>>>>>>>>>> 扣除库存成功，剩余：" + lastNumber);
                } else { 
                    System.out.println(">>>>>>>>>>> 扣除库存失败，库存不足");
                }
    
            } finally { 
                System.out.println(">>>>>>>>>>>>>>>>> 解除锁定");
                // 解锁
                lock.unlock();
            }
            return "success";
        }

## 三、注解aop的方式加Redisson实现分布式锁（推荐） ##

// 定义注解类

@Target({ ElementType.METHOD,ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface LockAction { 
    
        /** * 锁的名称 */
        String value() default "";
    
        /** * 描述 */
        String description() default "";
    
        /** * 等待锁超时时间，默认 30 * @return */
        long waitTime() default 30;
    
        /** * 自动解锁时间，自动解锁时间一定得大于方法执行时间，否则会导致锁提前释放，默认100 * @return */
        long leaseTime() default 100;
    
        /** * 时间单位，默认为 秒 * @return */
        TimeUnit timeUnit() default TimeUnit.SECONDS;
    
        /** * 默认：可重入锁 * @return */
        LockTypeEnum lockType() default LockTypeEnum.REENTRANT_LOCK;
    
    }

// 定义AOP

@Slf4j
    @Aspect
    @Component
    @Order(1)   //order越小越是最先执行，但更重要的是最先执行的最后结束。order默认值是2147483647
    public class LockAspect implements ApplicationContextAware { 
    
        private final String LOCK_CODE = "lockCode";
    
        private final RedissonClient redissonClient;
    
        private ApplicationContext applicationContext;
    
        public LockAspect(RedissonClient redissonClient) { 
            this.redissonClient = redissonClient;
        }
    
        /** * 定义公共的切点 */
        @Pointcut("@annotation(LockAction)")
        public void log(){ 
    
        }
    
        /** * 环绕通知 * @param joinPoint * @return * @throws Throwable */
        @Around(value = "@annotation(lockAction)")
        public Object around(ProceedingJoinPoint joinPoint,LockAction lockAction) throws Throwable { 
    
            String code = IdUtil.fastSimpleUUID();
            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder
                    .getRequestAttributes();
            HttpServletRequest request = Objects.requireNonNull(attributes).getRequest();
            String remoteUser = request.getRemoteUser();
            log.info(">>>>>>>>>>>> remoteUser 远程用户：{}",remoteUser);
            String requestURI = request.getRequestURI();
            log.info(">>>>>>>>>>>> requestURI 请求地址：{}",requestURI);
            request.setAttribute(LOCK_CODE, code);
    
            RLock lock = redissonClient.getLock(lockAction.value());
            Object proceed = null;
            try { 
            // lock.lock(); // 这种方式最稳妥，框架自动续期
            // 采用自定义时间的方式，注意时间长短
                boolean b = lock.tryLock(lockAction.waitTime(), lockAction.leaseTime(), lockAction.timeUnit());
                if (b) { 
                    // 类似于 method.invoke 方法
                    System.out.println(">>>>>>>>>>>>>>>>>>> 加锁成功");
                    proceed = joinPoint.proceed();
                }
            } finally { 
                lock.unlock();
                System.out.println(">>>>>>>>>>>>>>>>>>> 解锁成功");
            }
    
            // 第一个参数
    // String seckillId = joinPoint.getArgs()[0].toString();
            // 方法名
    // String name = joinPoint.getSignature().getName();
    // Class declaringType = joinPoint.getSignature().getDeclaringType();
    // Method[] methods = declaringType.getMethods();
    // Object proceed = null;
    // for (Method method : methods) { 
    // if(name.equals(method.getName())){ 
    // // 获得方法上面的注解
    // String value = AnnotationUtil
    // .getAnnotationValue(method, LockAction.class, "value");
    // if (StrUtil.isEmpty(value)){ 
    // throw new RuntimeException("运行时发生异常");
    // }
    // // 获取锁
    // RLock lock = redissonClient.getLock(value);
    // try { 
    // // 加锁,加锁结果
    // lock.lock();
    // System.out.println(">>>>>>>>>>>>>>>>>>> 枷锁成功");
    // // 类似于 method.invoke 方法
    // proceed = joinPoint.proceed();
    // } finally { 
    // System.out.println(">>>>>>>>>>>>>>>> 解除锁定");
    // lock.unlock();
    // }
    // }
    // }
            return proceed;
        }
    
        /** * 异常通知，当目标方法抛出异常时，该方法会被触发 * @param joinPoint */
        @AfterThrowing(value = "log()",throwing = "e")
        public void afterThrowing(JoinPoint joinPoint, Exception e){ 
            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
            HttpServletRequest request = Objects.requireNonNull(attributes).getRequest();
            String code = (String) request.getAttribute(LOCK_CODE);
            log.info(">>>>>>>>>> 错误码：{}", code);
        }
    
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { 
            this.applicationContext = applicationContext;
        }
    }

// 分布式锁 注解实战使用

@LockAction(value = "lockey")
        @GetMapping("/order/{parameter}")
        public String order(@PathVariable("parameter") String parameter) { 
            String stock = stringRedisTemplate.opsForValue().get("stock");
            int number = Integer.parseInt(stock);
            if (number > 0) { 
                Long lastNumber = stringRedisTemplate.opsForValue().decrement("stock");
                System.out.println(">>>>>>>>>>> 扣除库存成功，剩余：" + lastNumber);
            } else { 
                System.out.println(">>>>>>>>>>> 扣除库存失败，库存不足");
            }
            return "success";
        }