苏宁网站开发人员数据分析培训班

我的做法：通过切面配合注解的方式使用。

注意：切面不能应用于静态方法，私有方法，注解要被代理对象调用。

1.注解

@Inherited
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface RedisLock {String name() default "";String key() default "";int waitTime() default 5;int expireTime() default -1;TimeUnit timeUnit() default TimeUnit.SECONDS;String notes() default "";String[] tags() default {""};
}

 2.切面

@Aspect
@Component
public class RedisLockAspect {private static final Logger LOGGER = LoggerFactory.getLogger(RedisLockAspect.class);private static final String REDISSON_LOCK_PREFIX = "redisson_lock:";@Lazy@Resourceprivate RedissonClient redissonClient;/*** 定义切点*/@Pointcut("@annotation(mairuirobot.iwarehousecontrol.framework.functions.iwc.redis.annotation.RedisLock)")public void redisLockPointcut() {}/*** 环绕通知*/@Around("redisLockPointcut()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {String comment;// 获取方法上的注解 RedisLockMethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();Method method = methodSignature.getMethod();RedisLock redisLock = method.getAnnotation(RedisLock.class);String name = redisLock.name();String spel = redisLock.key();String key = getRedisKey(joinPoint, name, spel);RLock rLock = redissonClient.getLock(key);boolean lock = false;Object result = null;try {// long waitTime-获取锁的等待时长；long leaseTime-持有锁的时间，-1代表默认启动看门狗机制；TimeUnit unit-时间单位lock = rLock.tryLock(redisLock.waitTime(), redisLock.expireTime(), redisLock.timeUnit());if (!lock) {comment = String.format("Redis key[%s] lock failed, it's a repeated message", key);LOGGER.error(comment);Class<?> clazz = ((MethodSignature) joinPoint.getSignature()).getReturnType();if (GeneralResponse.class == clazz) {return GeneralResponse.failure();}if (boolean.class == clazz || Boolean.class == clazz) {return false;}return GeneralResponse.failure();}result = joinPoint.proceed();} finally {if (lock) {try {rLock.unlock();} catch (IllegalMonitorStateException e) {comment = String.format("Redis key[%s] unlock failed: errMsg = ", key);LOGGER.error(comment, e);}} else {comment = String.format("Current thread did not acquire the redis key[%s] lock, skipping unlock", key);LOGGER.error(comment);}}return result;}private String getRedisKey(ProceedingJoinPoint joinPoint, String lockName, String spel) {Object[] arguments = joinPoint.getArgs();String key = REDISSON_LOCK_PREFIX + lockName + ":" + SpelUtil.parse(spel, arguments);return key;}
}

3.解析方法（需要根据你实际情况进行修改）

public class SpelUtil {public static String parse(String spel, Object[] args) {if (spel == null || spel.isEmpty()) return "";Map<Object, Object> resMap = new HashMap<>();String[] split = spel.split("\\.");Arrays.stream(args).forEach(arg -> {JSONObject jsonObject = JSONObject.parseObject(JSONObject.toJSONString(arg));jsonObject.forEach((key, value) -> {if (value instanceof JSONObject) {((JSONObject) value).forEach((k, v) -> {resMap.put(k, v);});} else {resMap.put(key, value);}});});try {String key = split[split.length - 1];Object value = resMap.get(key);return (value != null) ? value.toString() : "";} catch (Exception e) {throw new RuntimeException("redisson参数解析失败: " + spel, e);}}
}

4.注册bean 

@Configuration
public class MyRedisRegistration {@Value("${redisson.address:}")private String redissonAddress;@Value("${redisson.password:}")private String redissonPassword;@Beanpublic RedissonClient redissonClient() {Config config = new Config();config.useSingleServer().setAddress(redissonAddress).setPassword(redissonPassword);return Redisson.create(config);}
}

 场景：申请电梯资源的时候，会有很多请求进来，导致电梯资源被争夺，这时就需要锁定电梯资源，防止同一个设备被抢占。