javax.validation - BindingResult

1. Writing the received parameter object parameters, using @ NotBlank, @ NotNull annotation

javax.validation.constraints.NotBlank Import; 
Import javax.validation.constraints.NotNull; 

@Data 
public class AbcParam { 

    @NotBlank (the Message = "Course name can not be") 
    Private String title; 

    @NotNull (the Message = "price can not be empty ") 
    Private Integer. price; 
} 

2. use Controller Write enable @Valid parameter check, and the BindingResult parameter (action: With the parameter, the parameter still be injected into the distal abcParam, parameter validation fails does not throw 400, bindingResult parameters include authentication failure information)

import javax.validation.Valid;
import org.springframework.validation.BindingResult;

@RestController
@RequestMapping(value = "/abc")
public class AbcController {

　　@PostMapping(value = "/save")
　　public Object save(@RequestBody @Valid AbcParam abcParam, BindingResult bindingResult){

   　　boolean hasErrors = bindingResult.hasErrors();
   　　if(hasErrors){
      　　List<String> errorMsgList = new ArrayList<String>();
      　　List<FieldError> errors =  bindingResult.getFieldErrors();
      　　for (FieldError error:errors) {
         　　String errorMsg =  error.getDefaultMessage();
         　　errorMsgList.add(errorMsg);
      　　}
 　　　　　return errorMsgList;
   　　}
   　　return abcParam;
　　}
}

3. Test, will enter the controller