序

本文主要研究下webflux如何进行参数校验

使用javax.validation

domain

import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;public class User {@Min(1)private long id;@NotEmptyprivate String name;@Min(20)private int age;//...
}

通过onErrorResume处理异常

• form表单提交

    /*** curl -i -X POST -d 'id=-1&name=a&age=10' http://localhost:8080/user/validate-mono** curl -i -X POST -d 'id=2&name=a&age=10' http://localhost:8080/user/validate-mono** curl -i -X POST -d 'id=2&name=a&age=30' http://localhost:8080/user/validate-mono* @param user* @return*/@PostMapping("/validate-mono")public Mono<String> formValidate(@Validated Mono<User> user) {return user.map(u -> "Hello " + u.getName()).onErrorResume(WebExchangeBindException.class, e -> Mono.just(bindingResult2String(e.getBindingResult())));}

• post json

    /*** curl -i -H "Content-Type: application/json" -X POST -d '{"id":-11,"name":"a"}' http://localhost:8080/user/validate-mono-json-body** curl -i -H "Content-Type: application/json" -X POST -d '{"id":12,"name":"a","age":30}' http://localhost:8080/user/validate-mono-json-body* @param user* @return*/@PostMapping(value = "/validate-mono-json-body",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)@ResponseBodypublic Mono<String> requestBodyValidate(@Validated @RequestBody Mono<User> user) {return user.map(u -> "Hello " + u.getName()).onErrorResume(WebExchangeBindException.class, e -> Mono.just(bindingResult2String(e.getBindingResult())));}

注意这里catch住WebExchangeBindException

通过ExceptionHandler处理WebExchangeBindException

• ExceptionHandler

    @ExceptionHandler(WebExchangeBindException.class)@ResponseStatus(HttpStatus.BAD_REQUEST)@ResponseBodypublic String handleBindException(WebExchangeBindException bindException) {return bindingResult2String(bindException.getBindingResult());}

• from表单提交

    /*** curl -i -X POST -d 'id=-1&name=a&age=10' http://localhost:8080/user/validate-mono** curl -i -X POST -d 'id=2&name=a&age=10' http://localhost:8080/user/validate-mono** curl -i -X POST -d 'id=2&name=a&age=30' http://localhost:8080/user/validate-mono* @param user* @return*/@PostMapping(value = "/validate-mono",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)public Mono<String> formValidate(@Validated Mono<User> user) {return user.map(u -> "Hello " + u.getName());}

注意这里要标注produces = MediaType.APPLICATION_JSON_UTF8_VALUE，否则报406 Not Acceptable

• post json

    /*** curl -i -H "Content-Type: application/json" -X POST -d '{"id":-11,"name":"a"}' http://localhost:8080/user/validate-mono-json-body** curl -i -H "Content-Type: application/json" -X POST -d '{"id":12,"name":"a","age":30}' http://localhost:8080/user/validate-mono-json-body* @param user* @return*/@PostMapping(value = "/validate-mono-json-body",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)@ResponseBodypublic Mono<String> requestBodyValidate(@Validated @RequestBody Mono<User> user) {return user.map(u -> "Hello " + u.getName());}

注意这里没有使用onErrorResume来处理WebExchangeBindException，而是交给ExceptionHandler处理

手工校验

javax.validation虽然是方便，但是具体业务场景非常复杂，不是简单的单个字段校验就完事的，有的需要关联校验，这个时候javax.validation就无能为力了。这个时候可能就需要手工来写校验。

    /*** curl -i -X POST -d 'id=-1&name=a&age=10' http://localhost:8080/user/manual-validate** curl -i -X POST -d 'id=2&name=a&age=-1' http://localhost:8080/user/manual-validate* @param user* @return*/@PostMapping(value = "/manual-validate",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)public Mono<String> manualValidate(Mono<User> user){return user.flatMap(u -> {if(u.getAge() < 0){return Mono.error(new RuntimeException("age < 0"));}else{return Mono.just("success");}});}

小结

通过使用javax.validation自动校验及Mono.error手工校验，基本可以处理大多数webflux参数校验场景。

doc

• Webflux-Validation
• How to validate Mono when using Spring Reactive