1500字范文 > @slf4j注解_SpringBoot + Redis + 注解 + 拦截器实现接口幂等性校验

@slf4j注解_SpringBoot + Redis + 注解 + 拦截器实现接口幂等性校验

时间：2019-02-05 21:23:18

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

springbootredis@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:/wangzaiplus/springboot/tree/wxw

六、代码实现

1.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>

2.JedisUtil

package com.wangzaiplus.test.util;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.ponent;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool;@Component@Slf4jpublic class JedisUtil {@Autowiredprivate 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();}}}

3.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 {}

4.ApiIdempotentInterceptor拦截器

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 {@Autowiredprivate TokenService tokenService;@Overridepublic 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);}@Overridepublic void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {}@Overridepublic void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {}}

5.TokenServiceImpl

package com.wangzaiplus.test.service.impl;import com.mon.Constant;import com.mon.ResponseCode;import com.mon.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 mons.lang3.StringUtils;import mons.lang3.text.StrBuilder;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import javax.servlet.http.HttpServletRequest;@Servicepublic class TokenServiceImpl implements TokenService {private static final String TOKEN_NAME = "token";@Autowiredprivate JedisUtil jedisUtil;@Overridepublic 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());}@Overridepublic void checkToken(HttpServletRequest request) {String token = request.getHeader(TOKEN_NAME);if (StringUtils.isBlank(token)) {// header中不存在tokentoken = request.getParameter(TOKEN_NAME);if (StringUtils.isBlank(token)) {// parameter中也不存在tokenthrow 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());}}}

6.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*/@Beanpublic 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);}@Overridepublic void addInterceptors(InterceptorRegistry registry) {// 接口幂等性拦截器registry.addInterceptor(apiIdempotentInterceptor());super.addInterceptors(registry);}@Beanpublic 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.mon.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@RequestMapping("/token")public class TokenController {@Autowiredprivate TokenService tokenService;@GetMappingpublic 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.mon.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")@Slf4jpublic class TestController {@Autowiredprivate TestService testService;@ApiIdempotent@PostMapping("testIdempotence")public ServerResponse testIdempotence() {return testService.testIdempotence();}}

3.获取token

查看redis

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

5.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"

八、注意点(非常重要)

上图中, 不能单纯的直接删除token而不校验是否删除成功, 会出现并发安全性问题, 因为, 有可能多个线程同时走到第46行, 此时token还未被删除, 所以继续往下执行, 如果不校验jedisUtil.del(token)的删除结果而直接放行, 那么还是会出现重复提交问题, 即使实际上只有一次真正的删除操作, 下面重现一下

稍微修改一下代码:

再次请求

再看看控制台

虽然只有一个真正删除掉token, 但由于没有对删除结果进行校验, 所以还是有并发问题, 因此, 必须校验