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This article mainly shows you "SpringBoot + Redis how to solve the problem of repeated submission", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "SpringBoot + Redis how to solve the problem of repeated submission" this article.

In development, an exposed interface may face a large number of repeated requests in an instant. If you want to filter out the damage to the business caused by repeated requests, you need to achieve idempotency.

Idempotent:

The impact of any multiple execution is the same as that of a single execution. The ultimate meaning is that the impact on the database can only be one-off, can not be repeated processing.

Solution:

The establishment of a unique index in the database can ensure that only one piece of data is eventually inserted into the database.

Token mechanism: get a token before each API request, and then add the token to the header body of the request next time. The background verifies it. If the verification passes the deletion of token, the token will be judged again in the next request (used in this case).

Pessimistic lock or optimistic lock can guarantee that other sql cannot update data every time for update (when the database engine is innodb, the condition of select must be a unique index to prevent locking the whole table)

First query and then judge, first by querying whether there is data in the database. If the existence proof has already been requested, reject the request directly. If it does not exist, it is proved to be the first time to come in and release it directly.

First, set up the Redis service package com.ckw.idempotence.service;/** * @ author ckw * @ version 1.0 * @ date on 2020-6-11 9:42 * @ description: redis tool class * / 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 utility class * / @ Componentpublic 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 } / * write cache * * @ 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;} / * write cache setting aging time * * @ param key * @ param value * @ return * / public boolean setEx (final String key, Object value, Long expireTime) {boolean result = false Try {ValueOperations operations = redisTemplate.opsForValue (); operations.set (key, value); redisTemplate.expire (key, expireTime, TimeUnit.SECONDS); result = true;} catch (Exception e) {e.printStackTrace ();} return result } / * determine whether there is a corresponding value * * @ param key * @ return * / public boolean exists (final String key) {return redisTemplate.hasKey (key);} / * read cache * @ param key * @ return * / public Object get (final String key) {Object o = null ValueOperations valueOperations = redisTemplate.opsForValue (); return valueOperations.get (key);} / * Delete the corresponding value * @ param key * / public Boolean remove (final String key) {if (exists (key)) {return redisTemplate.delete (key);} return false;}} II. Custom comments

Function: when intercepting a request, the interceptor determines whether the Controller method corresponding to the called address has a custom annotation, and sometimes indicates that the interface method is idempotent.

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 {} III. Token creates and verifies 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 Service * / @ Servicepublic class TokenService {@ Autowired RedisService redisService / / create token public String createToken () {/ / use UUID to represent token UUID uuid = UUID.randomUUID (); String token = uuid.toString (); / / deposit redis boolean b = redisService.setEx (token, token, 10000L); return token } / / verify whether there is token public boolean checkToken (HttpServletRequest request) {String token = request.getHeader ("token") in the request header or request parameters; / / if the header is empty if (StringUtils.isEmpty (token)) {/ / get token = request.getParameter ("token") from the request If (StringUtils.isEmpty (token)) {throw new BaseException (20001, "missing parameter token");}} / / if the token obtained from header is incorrect if (! redisService.exists (token)) {throw new BaseException (20001, "cannot repeat submission-token is incorrect, empty") } / / token correctly removes token if (! redisService.remove (token)) {throw new BaseException (20001, "token removal failed");} return true;}}

Custom exceptions and custom response bodies are used here as follows

Custom exception:

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: custom exception class * / @ Data@AllArgsConstructor@NoArgsConstructorpublic class BaseException extends RuntimeException {private Integer code; private String msg;}

Set up uniform exception handling:

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 20:45 on 2020-5-16 * @ description: unified exception handler * / @ ControllerAdvicepublic 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 ());}}

Custom response body:

Package com.ckw.idempotence.utils;import lombok.Data;import java.util.HashMap;import java.util.Map;/** * @ author ckw * @ version 1.0 * @ date on 2020-5-16 18:35 * @ description: return result * / @ Datapublic class R {private Boolean success; private Integer code; private String message; private Map data = new HashMap () Private R () {} / / Encapsulation returns success public static R ok () {R r = new R (); r.setSuccess (true); r.setCode (ResultCode.SUCCESS); r.setMessage ("success"); return r;} / / Encapsulation returns failure public static R error () {R r = new R (); r.setSuccess (false) R.setCode (ResultCode.ERROR); r.setMessage (failure); 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 map) {this.setData (map); return this;}}

Custom response codes:

Package com.ckw.idempotence.utils;import lombok.Data;import java.util.HashMap;import java.util.Map;/** * @ author ckw * @ version 1.0 * @ date on 2020-5-16 18:35 * @ description: return result * / @ Datapublic class R {private Boolean success; private Integer code; private String message; private Map data = new HashMap () Private R () {} / / Encapsulation returns success public static R ok () {R r = new R (); r.setSuccess (true); r.setCode (ResultCode.SUCCESS); r.setMessage ("success"); return r;} / / Encapsulation returns failure public static R error () {R r = new R (); r.setSuccess (false) R.setCode (ResultCode.ERROR); r.setMessage (failure); 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 map) {this.setData (map); return this;}} IV. Interceptor configuration

1. Interceptor configuration class

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: interceptor configuration class * / @ Configurationpublic class WebConfiguration implements WebMvcConfigurer {@ Autowired private AutoIdempotentInterceptor autoIdempotentInterceptor; @ Override public void addInterceptors (InterceptorRegistry registry) {registry.addInterceptor (autoIdempotentInterceptor);}}

2. Interceptor class

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 on 2020-6-11 10:11 * @ description: intercept repeatedly submitted data * / @ Componentpublic 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 () / / get the custom annotation AutoIdempotent annotation = method.getAnnotation (AutoIdempotent.class) above the method; / / if it is not equal to null, it means that the method needs idempotent if (null! = annotation) {return tokenService.checkToken (request);} return true;}} V. Normal Sevice class package com.ckw.idempotence.service;import org.springframework.stereotype.Service / * * @ author ckw * @ version 1.0 * @ date on 2020-6-11 10:04 * @ description: * / @ Servicepublic class TestService {public String testMethod () {return "normal business logic";}} VI. Controller class 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);} / / equivalent to adding a data interface (continuously clicking the add data button during the test to see whether the result is to add one or more data) @ AutoIdempotent @ PostMapping ("/ test/addData") public R addData () {String s = testService.testMethod (); return R.ok () .data ("data", s) 7. Testing

First click:

Second click:

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