在 Spring Boot 项目中使用 Redisson 实现双写一致性（即数据库和缓存的一致性），可以通过自定义注解和 AOP（面向切面编程）来简化代码并提高可维护性。以下是一个具体的案例，展示了如何使用自定义注解和 AOP 来实现这一目标。

实现步骤

1.添加依赖：

首先，确保你的项目中包含了 Redisson 和 Spring Boot 的依赖。

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
</dependency><!-- Redisson -->
<dependency><groupId>org.redisson</groupId><artifactId>redisson-spring-boot-starter</artifactId><version>3.16.3</version>
</dependency>

2.配置 Redisson：

在 application.yml 中配置 Redisson 客户端连接到 Redis 服务器。

spring:redis:host: localhostport: 6379redisson:singleServerConfig:address: redis://${spring.redis.host}:${spring.redis.port}

3.添加配置类：

@Configuration
public class RedissonConfig {@Value("${redisson.singleServerConfig.address}")private String redisAddress;@Bean(destroyMethod = "shutdown")public RedissonClient redissonClient() {Config config = new Config();config.useSingleServer().setAddress(redisAddress);return Redisson.create(config);}
}

 4.自定义注解：

创建一个自定义注解,另一个注解还用上篇的

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface CustomerCacheEvict {/*** 缓存名称* @return*/String key() default "";
}

5.AOP 切面：

创建一个切面类 CustomCacheAspect，使用 Redisson 的读写锁来实现缓存和数据库的一致性。

@Aspect
@Component
public class CustomCacheAspect {@Resourceprivate RedisTemplate<String, Object> redisTemplate;@Resourceprivate RedissonClient redissonClient;@Around("@annotation(customCacheable)")public Object cache(ProceedingJoinPoint joinPoint, CustomCacheable customCacheable) throws Throwable {Object result;String key = customCacheable.key();long expireTime = customCacheable.expireTime();//获取参数值key = getKey(joinPoint, key);// 加锁RLock rLock = redissonClient.getReadWriteLock(key+":lock").readLock();rLock.lock();try {// 尝试从缓存中获取数据Object cachedValue = redisTemplate.opsForValue().get(key);if (cachedValue != null) {return cachedValue;}// 读锁升级为写锁，执行数据库查询操作    rLock.unlock();RLock wLock = redissonClient.getReadWriteLock(key + ":lock").writeLock();wLock.lock();try {// 再次检查缓存，避免在获取写锁期间，其他线程已填充缓存cachedValue = redisTemplate.opsForValue().get(key);if (cachedValue != null) {return cachedValue; // 直接返回缓存值}// 如果缓存中没有数据，则执行方法并将结果存入缓存result = joinPoint.proceed();// 设置缓存if(expireTime > 0){redisTemplate.opsForValue().set(key, result, expireTime, TimeUnit.SECONDS);}else{redisTemplate.opsForValue().set(key, result);}}finally{if(wLock.isHeldByCurrentThread()) {wLock.unlock();}}}finally{if(rLock.isHeldByCurrentThread()){rLock.unlock();}}return result;}@Around("@annotation(customerCacheEvict)")public Object cache(ProceedingJoinPoint joinPoint, CustomerCacheEvict customerCacheEvict) throws Throwable {Object result;String key = customerCacheEvict.key();//获取参数值key = getKey(joinPoint, key);// 加锁RLock wLock = redissonClient.getReadWriteLock(key + ":lock").writeLock();wLock.lock();try {result = joinPoint.proceed();try {Thread.sleep(100);}catch (Exception e){e.printStackTrace();}redisTemplate.delete(key);}finally{if(wLock.isHeldByCurrentThread()){wLock.forceUnlock();}}return result;}/*** 获取参数值* @return*/private String getKey(ProceedingJoinPoint joinPoint, String key) {Object[] args = joinPoint.getArgs();// 构建缓存键if (args != null && args.length > 0) {key = key + ":" + args[0];}return key;}
}

6.服务类：

在接口类中使用自定义注解。（实际加到service 层更好）

    /*** 根据id查询*/@GetMapping("/{id}")@CustomCacheable(key = "user")public  UserTest getById(@PathVariable Long id) {return userTestService.getById(id);}/*** 修改*/@PutMapping("/{id}")@CustomerCacheEvict(key="user")public boolean update(@PathVariable Integer id, @RequestBody UserTest userTest) {userTest.setId(id);return userTestService.updateById(userTest);}

通过以上步骤，我们使用自定义注解和 AOP 确保了数据库和 Redis 缓存之间的一致性。