分组校验

package com.example.demo.test;

import lombok.Data;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.util.Set;

@Data
public class Student {

    //主键
    @NotNull(message="学生id不能为空",groups = {Update.class})
    private String id;

    //名称
    @NotNull(message="姓名不能为空",groups = {Add.class,Update.class})
    @Size(min=1, max=6,message="姓名长度为1~6",groups = {Add.class,Update.class})
    private String name;
    

    public interface Add{
    }

    public interface Update{
    }
    
    //验证代码
    public static void main(String[] args) {
        Student stu = new Student();
        validate(stu,Student.Update.class);   //更新情况下的校验
        
        Student stu1 = new Student();
        stu1.setId("1");
        validate(stu,Student.Add.class);//新增情况下的校验
    }

    private static void validate(Object o,Class group){
        ValidatorFactory vf = Validation.buildDefaultValidatorFactory();
        Validator validator = vf.getValidator();
        Set<ConstraintViolation<Object>> set = validator.validate(o, group);
        for (ConstraintViolation<Object> constraintViolation : set) {
            System.out.println(constraintViolation.getPropertyPath()+":"+constraintViolation.getMessage());
        }
    }

}

运行mian函数结果如下：

手动实现参数校验

一般情况下，我们都是在springMVC的controller就行参数校验，由框架完成校验，那如何实现自己在其他地方，比如服务层，甚至在dao层进行校验呢？

其实springMVC也是调用了ValidatorImpl这个类，如图所示：

所以，我们可以使用ValidatorFactory实现手动的参数校验：

package com.example.demo.test;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import java.util.Set;

class Test{
    private static class User {

        @NotNull(message = "姓名不能为空")
        private String name;
        @Min(value = 1 ,message = "年龄不能小于0")
        @NotNull(message = "age不能为空")
        private Integer age;
        @NotNull(message = "id不能为空")
        private Integer id;
        //省略get set方法
    }

    //验证代码
    public static void main(String[] args) {
        User user = new User();
        validate(user);
    }

    private static void validate(Object o){
        ValidatorFactory vf = Validation.buildDefaultValidatorFactory();
        Validator validator = vf.getValidator();
        Set<ConstraintViolation<Object>> set = validator.validate(o);
        for (ConstraintViolation<Object> constraintViolation : set) {
            System.out.println(constraintViolation.getPropertyPath()+":"+constraintViolation.getMessage());
        }
    }
}

执行结果如下：