Why can't I use Valid parameter along with RequestParam in Spring MVC?

Question

Example:

public String getStudentResult(@RequestParam(value = "regNo", required = true) String regNo, ModelMap model){

How can I use @valid for the regNo parameter here?

Solution 1

Late answer. I encounter this problem recently and find a solution. You can do it as follows, Firstly register a bean of MethodValidationPostProcessor:

@Bean
public MethodValidationPostProcessor methodValidationPostProcessor() {
    return new MethodValidationPostProcessor();
}

and then add the @Validated to the type level of your controller:

@RestController
@Validated
public class FooController {
    @RequestMapping("/email")
    public Map<String, Object> validate(@Email(message="请输入合法的email地址") @RequestParam String email){
    Map<String, Object> result = new HashMap<String, Object>();
    result.put("email", email);
    return result;
    }
}

And if user requested with a invalid email address, the ConstraintViolationException will be thrown. And you can catch it with:

@ControllerAdvice
public class AmazonExceptionHandler {

@ExceptionHandler(ConstraintViolationException.class)
@ResponseBody
@ResponseStatus(HttpStatus.BAD_REQUEST)
public String handleValidationException(ConstraintViolationException e){
    for(ConstraintViolation<?> s:e.getConstraintViolations()){
        return s.getInvalidValue()+": "+s.getMessage();
    }
    return "请求参数不合法";
}

}

You can check out my demo here

Solution 2

@Valid can be used to validate beans. I have'nt seen it used on single string parameters. Also it requires a validator to be configured.

The @Valid annotation is part of the standard JSR-303 Bean Validation API, and is not a Spring-specific construct. Spring MVC will validate a @Valid object after binding so-long as an appropriate Validator has been configured.

Reference : http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html

Comments

[sofs1]

Thanks for answering. May I know how can I validate a single String parameter for my Spring MVC project to validate in Sever side.

[sofs1]

2) My another question is, can I use both @ModelAttribute and @RequestParam(value = "regNo", required = true) together?

[Grant Lay]

The MethodValidationPostProcessor bean was the missing piece of the puzzle for me. Thanks.