SpringBoot + Redis如何解决重复提交问题(幂等)
目录
- 幂等:
- 解决方案:
- 一、搭建Redis服务
- 二、自定义注解
- 三、Token创建和校验
- 四、拦截器配置
- 五、正常Sevice类
- 六、Controller类
- 七、测试
在开发中,一个对外暴露的接口可能会面临瞬间的大量重复请求,如果想过滤掉重复请求造成对业务的伤害,那就需要实现幂等
幂等:
任意多次执行所产生的影响均与一次执行的影响相同。最终的含义就是 对数据库的影响只能是一次性的,不能重复处理。
解决方案:
- 数据库建立唯一性索引,可以保证最终插入数据库的只有一条数据
- token机制,每次接口请求前先获取一个token,然后再下次请求的时候在请求的header体中加上这个token,后台进行验证,如果验证通过删除token,下次请求再次判断token(本次案例使用)
- 悲观锁或者乐观锁,悲观锁可以保证每次for update的时候其他sql无法update数据(在数据库引擎是innodb的时候,select的条件必须是唯一索引,防止锁全表)
- 先查询后判断,首先通过查询数据库是否存在数据,如果存在证明已经请求过了,直接拒绝该请求,如果没有存在,就证明是第一次进来,直接放行
一、搭建Redis服务
package com.ckw.idempotence.service; /** * @author ckw * @version 1.0 * @date 2020/6/11 9:42 * @description: redis工具类 */ import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.ValueOperations; import org.springframework.data.redis.serializer.RedisSerializer; import org.springframework.data.redis.serializer.StringRedisSerializer; import org.springframework.stereotype.Component; import java.io.Serializable; import java.util.concurrent.TimeUnit; /** * redis工具类 */ @Component public class RedisService { private RedisTemplate redisTemplate; @Autowired(required = false) public void setRedisTemplate(RedisTemplate redisTemplate) { RedisSerializer stringSerializer = new StringRedisSerializer(); redisTemplate.setKeySerializer(stringSerializer); redisTemplate.setValueSerializer(stringSerializer); redisTemplate.setHashKeySerializer(stringSerializer); redisTemplate.setHashValueSerializer(stringSerializer); this.redisTemplate = redisTemplate; } /** * 写入缓存 * * @param key * @param value * @return */ public boolean set(final String key, Object value) { boolean result = false; try { ValueOperations operations = redisTemplate.opsForValue(); operations.set(key, value); result = true; } catch (Exception e) { e.printStackTrace(); } return result; } /** * 写入缓存设置时效时间 * * @param key * @param value * @return */ public boolean setEx(final String key, Object value, Long expireTime) { boolean result = false; try { ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue(); operations.set(key, value); redisTemplate.expire(key, expireTime, TimeUnit.SECONDS); result = true; } catch (Exception e) { e.printStackTrace(); } return result; } /** * 判断缓存中是否有对应的value * * @param key * @return */ public boolean exists(final String key) { return redisTemplate.hasKey(key); } /** * 读取缓存 * @param key * @return */ public Object get(final String key) { Object o = null; ValueOperations valueOperations = redisTemplate.opsForValue(); return valueOperations.get(key); } /** * 删除对应的value * @param key */ public Boolean remove(final String key) { if(exists(key)){ return redisTemplate.delete(key); } return false; } }
二、自定义注解
作用:拦截器拦截请求时,判断调用的地址对应的Controller方法是否有自定义注解,有的话说明该接口方法进行 幂等
package com.ckw.idempotence.annotion; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * @author ckw * @version 1.0 * @date 2020/6/11 9:55 * @description: */ @Target({ElementType.METHOD}) @Retention(RetentionPolicy.RUNTIME) public @interface AutoIdempotent { }
三、Token创建和校验
package com.ckw.idempotence.service; import com.ckw.idempotence.exectionhandler.BaseException; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.util.StringUtils; import javax.servlet.http.HttpServletRequest; import java.util.UUID; /** * @author ckw * @version 1.0 * @date 2020/6/11 9:56 * @description: token服务 */ @Service public class TokenService { @Autowired RedisService redisService; //创建token public String createToken() { //使用UUID代表token UUID uuid = UUID.randomUUID(); String token = uuid.toString(); //存入redis boolean b = redisService.setEx(token, token, 10000L); return token; } //检验请求头或者请求参数中是否有token public boolean checkToken(HttpServletRequest request) { String token = request.getHeader("token"); //如果header中是空的 if(StringUtils.isEmpty(token)){ //从request中拿 token = request.getParameter("token"); if(StringUtils.isEmpty(token)){ throw new BaseException(20001, "缺少参数token"); } } //如果从header中拿到的token不正确 if(!redisService.exists(token)){ throw new BaseException(20001, "不能重复提交-------token不正确、空"); } //token正确 移除token if(!redisService.remove(token)){ throw new BaseException(20001, "token移除失败"); } return true; } }
这里用到了自定义异常和自定义响应体如下
自定义异常:
package com.ckw.idempotence.exectionhandler; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; /** * @author ckw * @version 1.0 * @date 2020/5/16 20:58 * @description: 自定义异常类 */ @Data @AllArgsConstructor @NoArgsConstructor public class BaseException extends RuntimeException { private Integer code; private String msg; }
设置统一异常处理:
package com.ckw.idempotence.exectionhandler; import com.ckw.idempotence.utils.R; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.ResponseBody; /** * @author ckw * @version 1.0 * @date 2020/5/16 20:45 * @description: 统一异常处理器 */ @ControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(Exception.class) @ResponseBody public R error(Exception e){ e.printStackTrace(); return R.error(); } @ExceptionHandler(BaseException.class) @ResponseBody public R error(BaseException e){ e.printStackTrace(); return R.error().message(e.getMsg()).code(e.getCode()); } }
自定义响应体:
package com.ckw.idempotence.utils; import lombok.Data; import java.util.HashMap; import java.util.Map; /** * @author ckw * @version 1.0 * @date 2020/5/16 18:35 * @description: 返回结果 */ @Data public class R { private Boolean success; private Integer code; private String message; private Map<String, Object> data = new HashMap<String, Object>(); private R() { } //封装返回成功 public static R ok(){ R r = new R(); r.setSuccess(true); r.setCode(ResultCode.SUCCESS); r.setMessage("成功"); return r; } //封装返回失败 public static R error(){ R r = new R(); r.setSuccess(false); r.setCode(ResultCode.ERROR); r.setMessage("失败"); return r; } public R success(Boolean success){ this.setSuccess(success); return this; } public R message(String message){ this.setMessage(message); return this; } public R code(Integer code){ this.setCode(code); return this; } public R data(String key, Object value){ this.data.put(key, value); return this; } public R data(Map<String, Object> map){ this.setData(map); return this; } }
自定义响应码:
package com.ckw.idempotence.utils; import lombok.Data; import java.util.HashMap; import java.util.Map; /** * @author ckw * @version 1.0 * @date 2020/5/16 18:35 * @description: 返回结果 */ @Data public class R { private Boolean success; private Integer code; private String message; private Map<String, Object> data = new HashMap<String, Object>(); private R() { } //封装返回成功 public static R ok(){ R r = new R(); r.setSuccess(true); r.setCode(ResultCode.SUCCESS); r.setMessage("成功"); return r; } //封装返回失败 public static R error(){ R r = new R(); r.setSuccess(false); r.setCode(ResultCode.ERROR); r.setMessage("失败"); return r; } public R success(Boolean success){ this.setSuccess(success); return this; } public R message(String message){ this.setMessage(message); return this; } public R code(Integer code){ this.setCode(code); return this; } public R data(String key, Object value){ this.data.put(key, value); return this; } public R data(Map<String, Object> map){ this.setData(map); return this; } }
四、拦截器配置
1、拦截器配置类
package com.ckw.idempotence.config; import com.ckw.idempotence.interceptor.AutoIdempotentInterceptor; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.InterceptorRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; /** * @author ckw * @version 1.0 * @date 2020/6/11 10:07 * @description: 拦截器配置类 */ @Configuration public class WebConfiguration implements WebMvcConfigurer { @Autowired private AutoIdempotentInterceptor autoIdempotentInterceptor; @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(autoIdempotentInterceptor); } }
2、拦截器类
package com.ckw.idempotence.interceptor; import com.ckw.idempotence.annotion.AutoIdempotent; import com.ckw.idempotence.service.TokenService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import org.springframework.web.method.HandlerMethod; import org.springframework.web.servlet.HandlerInterceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.lang.reflect.Method; /** * @author ckw * @version 1.0 * @date 2020/6/11 10:11 * @description: 拦截重复提交数据 */ @Component public class AutoIdempotentInterceptor implements HandlerInterceptor { @Autowired private TokenService tokenService; @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { if(!(handler instanceof HandlerMethod)) return true; HandlerMethod handlerMethod = (HandlerMethod) handler; Method method = handlerMethod.getMethod(); //拿到方法上面的自定义注解 AutoIdempotent annotation = method.getAnnotation(AutoIdempotent.class); //如果不等于null说明该方法要进行幂等 if(null != annotation){ return tokenService.checkToken(request); } return true; } }
五、正常Sevice类
package com.ckw.idempotence.service; import org.springframework.stereotype.Service; /** * @author ckw * @version 1.0 * @date 2020/6/11 10:04 * @description: */ @Service public class TestService { public String testMethod(){ return "正常业务逻辑"; } }
六、Controller类
package com.ckw.idempotence.controller; import com.ckw.idempotence.annotion.AutoIdempotent; import com.ckw.idempotence.service.TestService; import com.ckw.idempotence.service.TokenService; import com.ckw.idempotence.utils.R; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; /** * @author ckw * @version 1.0 * @date 2020/6/11 9:58 * @description: */ @RestController @CrossOrigin @RequestMapping("/Idempotence") public class TestController { @Autowired private TokenService tokenService; @Autowired private TestService testService; @GetMapping("/getToken") public R getToken(){ String token = tokenService.createToken(); return R.ok().data("token",token); } //相当于添加数据接口(测试时 连续点击添加数据按钮 看结果是否是添加一条数据还是多条数据) @AutoIdempotent @PostMapping("/test/addData") public R addData(){ String s = testService.testMethod(); return R.ok().data("data",s); } }
七、测试
第一次点击:
第二次点击:
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