Springboot + redis + 注解 + 拦截器来实现接口幂等性校验

一时失言乱红尘 2023-06-30 04:24 11阅读 0赞

### 一、概念 ###

幂等性, 通俗的说就是一个接口, 多次发起同一个请求, 必须保证操作只能执行一次  
比如:

*  订单接口, 不能多次创建订单
 *  支付接口, 重复支付同一笔订单只能扣一次钱
 *  支付宝回调接口, 可能会多次回调, 必须处理重复回调
 *  普通表单提交接口, 因为网络超时等原因多次点击提交, 只能成功一次  
    等等

### 二、常见解决方案 ###

*  唯一索引 – 防止新增脏数据
 *  token机制 – 防止页面重复提交
 *  悲观锁 – 获取数据的时候加锁(锁表或锁行)
 *  乐观锁 – 基于版本号version实现, 在更新数据那一刻校验数据
 *  分布式锁 – redis(jedis、redisson)或zookeeper实现
 *  状态机 – 状态变更, 更新数据时判断状态

### 三、本文实现 ###

本文采用第2种方式实现, 即通过redis + token机制实现接口幂等性校验

### 四、实现思路 ###

为需要保证幂等性的每一次请求创建一个唯一标识token, 先获取token, 并将此token存入redis, 请求接口时, 将此token放到header或者作为请求参数请求接口, 后端接口判断redis中是否存在此token:

*  如果存在, 正常处理业务逻辑, 并从redis中删除此token, 那么, 如果是重复请求, 由于token已被删除, 则不能通过校验, 返回请勿重复操作提示
 *  如果不存在, 说明参数不合法或者是重复请求, 返回提示即可

### 五、项目简介 ###

*  springboot
 *  redis
 *  @ApiIdempotent注解 + 拦截器对请求进行拦截
 *  @ControllerAdvice全局异常处理
 *  压测工具: jmeter

说明:  
本文重点介绍幂等性核心实现, 关于springboot如何集成redis、ServerResponse、ResponseCode等细枝末节不在本文讨论范围之内, 有兴趣的小伙伴可以查看我的Github项目:  
[https://github.com/JavaAlliance/csdn-][https_github.com_JavaAlliance_csdn-]

### 六、代码实现 ###

**pom**

<dependency>
                <groupId>redis.clients</groupId>
                <artifactId>jedis</artifactId>
                <version>2.9.0</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.10</version>
            </dependency>

**JedisUtil**

package com.wangzaiplus.test.util;
    
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    import redis.clients.jedis.Jedis;
    import redis.clients.jedis.JedisPool;
    
    @Component
    @Slf4j
    public class JedisUtil { 
    
        @Autowired
        private JedisPool jedisPool;
    
        private Jedis getJedis() { 
            return jedisPool.getResource();
        }
    
        /** * 设值 * * @param key * @param value * @return */
        public String set(String key, String value) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.set(key, value);
            } catch (Exception e) { 
                log.error("set key:{} value:{} error", key, value, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 设值 * * @param key * @param value * @param expireTime 过期时间, 单位: s * @return */
        public String set(String key, String value, int expireTime) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.setex(key, expireTime, value);
            } catch (Exception e) { 
                log.error("set key:{} value:{} expireTime:{} error", key, value, expireTime, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 取值 * * @param key * @return */
        public String get(String key) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.get(key);
            } catch (Exception e) { 
                log.error("get key:{} error", key, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 删除key * * @param key * @return */
        public Long del(String key) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.del(key.getBytes());
            } catch (Exception e) { 
                log.error("del key:{} error", key, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 判断key是否存在 * * @param key * @return */
        public Boolean exists(String key) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.exists(key.getBytes());
            } catch (Exception e) { 
                log.error("exists key:{} error", key, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 设值key过期时间 * * @param key * @param expireTime 过期时间, 单位: s * @return */
        public Long expire(String key, int expireTime) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.expire(key.getBytes(), expireTime);
            } catch (Exception e) { 
                log.error("expire key:{} error", key, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        /** * 获取剩余时间 * * @param key * @return */
        public Long ttl(String key) { 
            Jedis jedis = null;
            try { 
                jedis = getJedis();
                return jedis.ttl(key);
            } catch (Exception e) { 
                log.error("ttl key:{} error", key, e);
                return null;
            } finally { 
                close(jedis);
            }
        }
    
        private void close(Jedis jedis) { 
            if (null != jedis) { 
                jedis.close();
            }
        }
    
    }

**自定义注解@ApiIdempotent**

package com.wangzaiplus.test.annotation;
    
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    /** * 在需要保证 接口幂等性 的Controller的方法上使用此注解 */
    @Target({ ElementType.METHOD})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface ApiIdempotent { 
    }

**ApiIdempotentInterceptor拦截器**  
（每次向后台发送请求都会经过拦截器的处理，所以在下面的preHandle（）方法的方法体里面写了处理token的逻辑代理）

package com.wangzaiplus.test.interceptor;
    
    import com.wangzaiplus.test.annotation.ApiIdempotent;
    import com.wangzaiplus.test.service.TokenService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.method.HandlerMethod;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.lang.reflect.Method;
    
    /** * 接口幂等性拦截器 */
    public class ApiIdempotentInterceptor implements HandlerInterceptor { 
    
        @Autowired
        private TokenService tokenService;
    
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) { 
            if (!(handler instanceof HandlerMethod)) { 
                return true;
            }
    
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
    
            ApiIdempotent methodAnnotation = method.getAnnotation(ApiIdempotent.class);
            if (methodAnnotation != null) { 
                check(request);// 幂等性校验, 校验通过则放行, 校验失败则抛出异常, 并通过统一异常处理返回友好提示
            }
    
            return true;
        }
    
        private void check(HttpServletRequest request) { 
            tokenService.checkToken(request);
        }
    
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception { 
        }
    
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception { 
        }
    }

**TokenServiceImpl**

package com.wangzaiplus.test.service.impl;
    
    import com.wangzaiplus.test.common.Constant;
    import com.wangzaiplus.test.common.ResponseCode;
    import com.wangzaiplus.test.common.ServerResponse;
    import com.wangzaiplus.test.exception.ServiceException;
    import com.wangzaiplus.test.service.TokenService;
    import com.wangzaiplus.test.util.JedisUtil;
    import com.wangzaiplus.test.util.RandomUtil;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang3.StringUtils;
    import org.apache.commons.lang3.text.StrBuilder;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import javax.servlet.http.HttpServletRequest;
    
    @Service
    public class TokenServiceImpl implements TokenService { 
    
        private static final String TOKEN_NAME = "token";
    
        @Autowired
        private JedisUtil jedisUtil;
    
        @Override
        public ServerResponse createToken() { 
            String str = RandomUtil.UUID32();
            StrBuilder token = new StrBuilder();
            token.append(Constant.Redis.TOKEN_PREFIX).append(str);
    
            jedisUtil.set(token.toString(), token.toString(), Constant.Redis.EXPIRE_TIME_MINUTE);
    
            return ServerResponse.success(token.toString());
        }
    
        @Override
        public void checkToken(HttpServletRequest request) { 
            String token = request.getHeader(TOKEN_NAME);
            if (StringUtils.isBlank(token)) { // header中不存在token
                token = request.getParameter(TOKEN_NAME);
                if (StringUtils.isBlank(token)) { // parameter中也不存在token
                    throw new ServiceException(ResponseCode.ILLEGAL_ARGUMENT.getMsg());
                }
            }
    
            if (!jedisUtil.exists(token)) { 
                throw new ServiceException(ResponseCode.REPETITIVE_OPERATION.getMsg());
            }
    
            Long del = jedisUtil.del(token);
            if (del <= 0) { 
                throw new ServiceException(ResponseCode.REPETITIVE_OPERATION.getMsg());
            }
        }
    
    }

**TestApplication**

package com.wangzaiplus.test;
    
    import com.wangzaiplus.test.interceptor.ApiIdempotentInterceptor;
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.cors.CorsConfiguration;
    import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
    import org.springframework.web.filter.CorsFilter;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    
    @SpringBootApplication
    @MapperScan("com.wangzaiplus.test.mapper")
    public class TestApplication  extends WebMvcConfigurerAdapter { 
    
        public static void main(String[] args) { 
            SpringApplication.run(TestApplication.class, args);
        }
    
        /** * 跨域 * @return */
        @Bean
        public CorsFilter corsFilter() { 
            final UrlBasedCorsConfigurationSource urlBasedCorsConfigurationSource = new UrlBasedCorsConfigurationSource();
            final CorsConfiguration corsConfiguration = new CorsConfiguration();
            corsConfiguration.setAllowCredentials(true);
            corsConfiguration.addAllowedOrigin("*");
            corsConfiguration.addAllowedHeader("*");
            corsConfiguration.addAllowedMethod("*");
            urlBasedCorsConfigurationSource.registerCorsConfiguration("/**", corsConfiguration);
            return new CorsFilter(urlBasedCorsConfigurationSource);
        }
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) { 
            // 接口幂等性拦截器
            registry.addInterceptor(apiIdempotentInterceptor());
            super.addInterceptors(registry);
        }
    
        @Bean
        public ApiIdempotentInterceptor apiIdempotentInterceptor() { 
            return new ApiIdempotentInterceptor();
        }
    
    }

OK, 目前为止, 校验代码准备就绪, 接下来测试验证

## 七、测试验证 ##

**1、获取token的控制器TokenController**

package com.wangzaiplus.test.controller;
    
    import com.wangzaiplus.test.common.ServerResponse;
    import com.wangzaiplus.test.service.TokenService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class TokenController { 
    
        @Autowired
        private TokenService tokenService;
    
        @RequestMapping("/token")
        public ServerResponse token() { 
            return tokenService.createToken();
        }
    
    }

**2、TestController, 注意@ApiIdempotent注解, 在需要幂等性校验的方法上声明此注解即可, 不需要校验的无影响**

package com.wangzaiplus.test.controller;
    
    import com.wangzaiplus.test.annotation.ApiIdempotent;
    import com.wangzaiplus.test.common.ServerResponse;
    import com.wangzaiplus.test.service.TestService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/test")
    @Slf4j
    public class TestController { 
    
        @Autowired
        private TestService testService;
    
        @ApiIdempotent
        @PostMapping("testIdempotence")
        public ServerResponse testIdempotence() { 
            return testService.testIdempotence();
        }
    
    }

**3、获取token**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3_size_16_color_FFFFFF_t_70]  
查看redis  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3_size_16_color_FFFFFF_t_70 1]  
**4、测试接口安全性: 利用jmeter测试工具模拟50个并发请求, 将上一步获取到的token作为参数**  
header或参数均不传token, 或者token值为空, 或者token值乱填, 均无法通过校验, 如token值为"abcd"

### 九、总结 ###

其实思路很简单, 就是每次请求保证唯一性, 从而保证幂等性, 通过拦截器+注解, 就不用每次请求都写重复代码, 其实也可以利用spring aop实现， 无所谓。

本文转载自：https://mp.weixin.qq.com/s?\_\_biz=MzA3ODQ0Mzg2OA==&mid=2649051174&idx=2&sn=184e79222628ec455be995961f386761&chksm=87535415b024dd0348b7d92594000f33b6c1cfe2049c467038d8652fb49a96d6c66e2ebb9c73&mpshare=1&scene=23&srcid=&sharer\_sharetime=1578967610377&sharer\_shareid=a747f30233a288baa38fb8e3ef05c1a9\#rd

[https_github.com_JavaAlliance_csdn-]: https://github.com/JavaAlliance/csdn-/tree/master/Springboot+%20redis+%20%E6%8B%A6%E6%88%AA%E5%99%A8%E6%9D%A5%E5%AE%9E%E7%8E%B0%E6%8E%A5%E5%8F%A3%E5%B9%82%E7%AD%89%E6%80%A7%E6%A0%A1%E9%AA%8C
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200115125327166.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200115125501634.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjQxOTU3,size_16,color_FFFFFF,t_70