在java spring中添加对年龄字段异常的自定义验证

Question

@Entity
@Table(name = "students")
public class Student {

    @NotNull
    @Column(name = "age")
    @Positive
    @Digits(fraction = 0, integer = 10, message ="add a digit msg")
    private int age;

    // more codes below
}

控制器

package com.crudtest.demo.controller;

import com.crudtest.demo.model.Student;
import com.crudtest.demo.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import javax.validation.Valid;

@RestController
@RequestMapping("/api")
public class StudentController {

   @Autowired
   private StudentService studentService;

   @PostMapping("/students")
    public ResponseEntity<Student> createStudent(@Valid @RequestBody Student student) {
    Student stud = studentService.create(student);
    return new ResponseEntity<>(stud, HttpStatus.CREATED);
 }
}

服务

@Service
public class StudentService {

  @Autowired
  private StudentRepository studentRepository;

  public Student create(Student student) {
     return studentRepository.save(student);
  }
}

储存库

@Repository
public interface StudentRepository extends JpaRepository<Student, Long> 
{}

我还尝试在这里添加自定义注释：

package //
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.Payload;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.FIELD) // inside field
@Retention(RetentionPolicy.RUNTIME)
public @interface AgeValidation {
   String message() default "Age must be a number and not greater than 200.";

  Class<?>[] groups() default {};

  public abstract Class<? extends Payload>[] payload() default {};
}

class AgeValidationInterface implements ConstraintValidator<AgeValidation, Integer> {

  @Override
  public boolean isValid(Integer age, ConstraintValidatorContext constraintValidatorContext) {
    return age > 0 && age < 200;
  }
}

并且还更新了

//Student.java
@AgeValidation
private int age;

但同样的错误结果。

如何使用自定义验证对此进行验证？

Answer 1

这不起作用的原因与Spring试图将发布的有效负载反序列化为具体对象（即student)时（通过Jackson）进行的类型转换有关。

您的有效负载应该包含符合反序列化条件的“1”或1（因为它们是有效数字）。提供的字符串不是有效的数字表示形式，因此进程失败，出现未处理的异常，从而导致“空白”响应。

您需要确保提供的JSON有效负载格式良好，并且有处理意外异常的好方法。