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This article mainly introduces "how to use custom annotation + Redis interceptor to achieve idempotent check". In daily operation, I believe many people have doubts about how to use custom annotation + Redis interceptor to realize idempotent check. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the question of "how to use custom annotations + Redis interceptor to achieve idempotent check"! Next, please follow the editor to study!

Realization method

Write a custom annotation and an interceptor. The custom annotation in this article can specify the incoming timeout (default is 60 seconds). The interceptor intercepts the method using annotations, obtains the passed parameters and timeout, splices one or more parameters into a json string, encrypts it with md5 and stores it in the Redis cache as key. If the same content can be found within the timeout range according to key, a prompt that the form content has been submitted is returned, otherwise the method continues.

Customize a @ Idempotent annotation

/ * * Custom anti-duplicate submission comments * / @ Retention (RetentionPolicy.RUNTIME) @ Target (ElementType.METHOD) public @ interface Idempotent {/ * * you can pass a specified limit time for repeated submission. Default is 60 seconds * / long value () default 60000;}

Customize an IdempotentAspect interceptor

/ * * interceptor * @ author bean sprouts * @ Date 2020-11-11 15:05 * / @ Aspect@Componentpublic class IdempotentAspect {private Logger logger = LoggerFactory.getLogger (IdempotentAspect.class); @ Autowired private RedisService redisService; @ Around ("@ annotation (idempotent)") public Object aroundMethod (ProceedingJoinPoint pjp,Idempotent idempotent) throws Throwable {/ * * get the parameters of the execution method * / Object [] args = pjp.getArgs () / * * get the timeout passed by the comment * / long timeOut = idempotent.value (); / * * encrypt the passed parameters using MD5 * / String encode = getMd5Value (args); try {/ * * verify whether it has been repeatedly submitted, and if not, store it in the Redis cache for the specified timeout * / boolean checkFormToken = redisService.checkForm (encode,timeOut) If (checkFormToken) {/ * * this is a custom exception class that you can write * / throw new CommonException (Code.RepeatSubmit, "form content has been submitted");} / * * continue to execute method * / return pjp.proceed () } catch (CommonException e) {logger.error ("Runtime error:" + e.getMessage (), e); if (Code.RepeatSubmit.getCode ()! = e.getCode ()) {/ * * other CommonException custom exceptions may exist in the calling method, and the checked key needs to be deleted. Repeated submission of * / redisService.delete (encode) is supported. } throw e;} catch (Exception e) {logger.error ("idempotent check error:" + e.getMessage (), e); throw e }} / * encrypt incoming parameters using MD5 * @ param args * @ return * / private String getMd5Value (Object [] args) {String md5 = "null"; if (args.length = = 0) {return md5;} else {StringBuilder jsonString = new StringBuilder (JSON.toJSONString (args)) / * * encrypt the string using the md5 utility class * / md5 = SecureUtil.md5Encode (jsonString.toString ());} return md5;}}

Encapsulated RedisService class

@ Componentpublic class RedisService {private Logger logger = LoggerFactory.getLogger (RedisService.class); @ Autowired private StringRedisTemplate stringRedisTemplate / * put objects in cache * @ param key key * @ param obj object data * @ param timeout timeout * / public void set (String key, Object obj, long timeout) {if (obj instanceof String) {stringRedisTemplate.opsForValue (). Set (key, (String) obj, timeout, TimeUnit.MILLISECONDS); return } String json = JSON.toJSONString (obj); stringRedisTemplate.opsForValue () .set (key, json, timeout, TimeUnit.MILLISECONDS) } / * query the data in the cache according to Key * @ param key * @ return * / public String get (final String key) {if (StringUtils.isEmpty (key)) {logger.warn ("get Redis cache, the incoming Key is empty"); return null;} return stringRedisTemplate.opsForValue () .get (key) } / * delete cache data according to key * @ param key * / public void delete (String key) {stringRedisTemplate.delete (key);} / * query whether the cache exists * @ param checkCase * @ return * / public boolean checkForm (String checkCase,long timeOut) {String cacheValue = get (checkCase) / * * if the query cache is not empty, return true*/ if (StringUtils.isNotEmpty (cacheValue)) {return true;} / * * otherwise store the object in the cache. IdUtil.randomUUID () generates utility classes for hutool's UUID, and you can load related dependencies * / set (checkCase, IdUtil.randomUUID (), timeOut); return false;} on the hutool official website.

Custom error code enumeration Code

Public enum Code {ErrorSystem (500,500, "system busy!") , RepeatSubmit (4, "repeat submission"); private int code; private String msg; Code (int code, String msg) {this.code = code; this.msg = msg;} public int getCode () {return code;} public String getMsg () {return msg;}}

Custom exception class CommonException

Public class CommonException extends RuntimeException {/ * * error code * / private int code = Code.ErrorSystem.getCode (); / * * error message * / private String msg = Code.ErrorSystem.getMsg (); public CommonException (Code code) {super ("[" + code.getCode () + ":" + code.toString () + "]" + code.getMsg ()); this.code = code.getCode () This.msg = code.getMsg ();} public CommonException (String msg) {super ("[" + Code.ErrorSystem.getCode () + ":" + Code.ErrorSystem.toString () + "]" + msg); this.code = Code.ErrorSystem.getCode (); this.msg = msg } public CommonException (Code code, String msg) {super ("[" + code.getCode () + ":" + code.toString () + "]" + msg); this.code = code.getCode (); this.msg = msg;} public int getCode () {return code;} public String getMsg () {return msg;}}

For test RedisController,@Idempotent annotations, you can directly value the parameter. This parameter can set the survival time of this request parameter in redis. If no parameter is passed, the default survival time is 60 seconds.

/ * * @ author bean sprouts * @ Date 2020-11-11 11:09 * / @ RestControllerpublic class RedisController {private Logger logger = LoggerFactory.getLogger (RedisController.class) / * * Custom annotations + Redis+MD5 encrypted interceptor implements idempotent check * @ param name * @ param age * @ return * / @ Idempotent @ RequestMapping (value = "/ auth/redis/idempotent", method = {RequestMethod.GET, RequestMethod.POST}) public String idempotentTest (String name,String age) {logger.info ("name:" + name); logger.info ("age:" + age) / / TODO executes save or update method return "executed successfully";}}

Successful execution was returned when the request was initiated for the first time

Then immediately initiate another request with the same parameter, and the system will throw an exception that "the form content has been submitted"

At this point, the study on "how to use custom annotations + Redis interceptor to achieve idempotent verification" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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