Spring Request Body Validation

You can check request body validation by using hibernate validator.

first of all, you can add the validation annotation to your request body class.

package org.blog.test.model;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.Length;
import org.hibernate.validator.constraints.NotEmpty;

import javax.validation.constraints.Max;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.io.Serializable;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class ValidationRequest implements Serializable {

    private static final long serialVersionUID = 2207905388150465893L;

    @Size(max = 2)
    private String numRange;

    @Email
    private String email;

}

@Size annotation checks string's length. If numRange's string length is over 2, it shows exception.
@Email annotation checks String's format whether it follows email format.

And then, you can add the @valid annotation to your controller class's request body part.

package org.blog.test.controller;

import org.blog.test.model.ValidationRequest;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;

@RestController
public class ValidationController {

    @RequestMapping(method = RequestMethod.POST, path = "/validate")
    public String checkValidation(@Valid @RequestBody ValidationRequest validationRequest) {
        return "success";
    }
}

Now, you can find the error message when you don't keep the constraint.

{
  "timestamp": 1482679824788,
  "status": 400,
  "error": "Bad Request",
  "exception": "org.springframework.web.bind.MethodArgumentNotValidException",
  "errors": [
    {
      "codes": [
        "Email.validationRequest.email",
        "Email.email",
        "Email.java.lang.String",
        "Email"
      ],
      "arguments": [
        {
          "codes": [
            "validationRequest.email",
            "email"
          ],
          "arguments": null,
          "defaultMessage": "email",
          "code": "email"
        },
        [],
        {
          "defaultMessage": ".*",
          "codes": [
            ".*"
          ],
          "arguments": null
        }
      ],
      "defaultMessage": "이메일 주소가 유효하지 않습니다.",
      "objectName": "validationRequest",
      "field": "email",
      "rejectedValue": "test",
      "bindingFailure": false,
      "code": "Email"
    }
  ],
  "message": "Validation failed for object='validationRequest'. Error count: 1",
  "path": "/validate"
}