在项目中，如何保证幂等性

在我们编程中常见幂等
1)select查询天然幂等  
2)delete删除也是幂等,删除同一个多次效果一样 
3)update直接更新某个值的,幂等 
4)update更新累加操作的,非幂等 
5)insert非幂等操作,每次新增一条

由于重复点击或者网络重发  eg:  
1)点击提交按钮两次;
2)点击刷新按钮;
3)使用浏览器后退按钮重复之前的操作，导致重复提交表单;
4)使用浏览器历史记录重复提交表单;
5)浏览器重复的HTTP请;
6)nginx重发等情况;
7)分布式RPC的try重发等;

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

spring:
  application:
    name: spring-cloud-product
  redis:
    port: 6379
    host: 127.0.0.1
    password:
    database: 0
    timeout: 2000

singleServerConfig:
  idleConnectionTimeout: 10000
  pingTimeout: 1000
  connectTimeout: 10000
  timeout: 3000
  retryAttempts: 3
  retryInterval: 1500
  reconnectionTimeout: 3000
  failedAttempts: 3
  password: null
  subscriptionsPerConnection: 5
  clientName: null
  address: "redis://127.0.0.1:6379"
  subscriptionConnectionMinimumIdleSize: 1
  subscriptionConnectionPoolSize: 50
  connectionMinimumIdleSize: 32
  connectionPoolSize: 64
  database: 0
  #在最新版本中dns的检查操作会直接报错 所以我直接注释掉了
  #dnsMonitoring: false
  dnsMonitoringInterval: 5000
threads: 0
nettyThreads: 0
codec: !<org.redisson.codec.JsonJacksonCodec> {}
transportMode : "NIO"

/**
* @Description //TODO
 * @author yun
 * @date 2021/04/02
 */
@Configuration
public class RedssonConfig {
    @Bean(destroyMethod="shutdown")
    public RedissonClient redisson() throws IOException {
        RedissonClient redisson = Redisson.create(
                Config.fromYAML(new ClassPathResource("redisson-single.yml").getInputStream()));
        return redisson;
    }
}

/**
 * redis 方案
 *
 * @author yun
 * @date 2021/04/02
 */
@Aspect
@Configuration
public class LockMethodInterceptor {

    @Autowired
    public LockMethodInterceptor(RedissonClient redissonClient, CacheKeyGenerator cacheKeyGenerator) {
        this.redissonClient = redissonClient;
        this.cacheKeyGenerator = cacheKeyGenerator;
    }

    
    private final RedissonClient redissonClient;
    private final CacheKeyGenerator cacheKeyGenerator;


    @Around("execution(public * *(..)) && @annotation(com.yunlong.annotation.CacheLock)")
    public Object interceptor(ProceedingJoinPoint pjp) {
        MethodSignature signature = (MethodSignature) pjp.getSignature();
        Method method = signature.getMethod();
        CacheLock lock = method.getAnnotation(CacheLock.class);
        if (StringUtils.isEmpty(lock.prefix())) {
            throw new RuntimeException("lock key don't null...");
        }
        // 上下文中获取请求表单的唯一标识
        final String lockKey = cacheKeyGenerator.getLockKey(pjp);
        String value = UUID.randomUUID().toString();
  	RLock lockR = redissonClient.getLock(lockKey);
        try {
            // 假设上锁成功，但是设置过期时间失效，以后拿到的都是 false
            final boolean success = lockR.isLocked();
            if (!success) {
                throw new RuntimeException("重复提交");
            }
	     	lockR.unlock();
            try {
                return pjp.proceed();
            } catch (Throwable throwable) {
                throw new RuntimeException("系统异常");
            }
        } finally {
            lockR.unlock(lockKey);
        }
    }
}