这里我们介绍以下自定义的校验器的简单的使用示例

一、包结构和主要文件

二、代码

1.自定义注解文件MyConstraint

package com.knyel.validator;import javax.validation.Constraint;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.METHOD,ElementType.FIELD})//注解可以标注在什么元素上@Retention(RetentionPolicy.RUNTIME)@Constraint(validatedBy = MyConstraintValidator.class)public @interface MyConstraint {    String message();    Class
     [] groups() default {};    Class
     [] payload() default {};}

2.自定义校验逻辑文件MyConstraintValidator

package com.knyel.validator;import com.knyel.service.HelloKnyel;import org.springframework.beans.factory.annotation.Autowired;import javax.validation.ConstraintValidator;import javax.validation.ConstraintValidatorContext;//ConstraintValidator
     
      //A参数：表示要验证的注解//T参数：表示要验证的东西是什么类型public class MyConstraintValidator implements ConstraintValidator
      
        {    @Autowired    HelloKnyel helloKnyel;    @Override    public void initialize (MyConstraint myConstraint){        //校验器初始化的时候做的一些工作        System.out.println("myvalidator init");    }    /*    真正的校验逻辑    Object o :传进来的校验的值    ConstraintValidatorContext constraintValidatorContext :校验的上下文     */    @Override    public boolean isValid (Object value, ConstraintValidatorContext constraintValidatorContext){        //处理校验逻辑        helloKnyel.welcome("knyel");        System.out.println(value);        //true代表校验成功，false代表校验失败        return false;    }}
      
     

3.在2中isValid方法中调用的校验逻辑业务HelloKnyelImpl及接口

package com.knyel.service;public interface HelloKnyel {    String welcome(String name);}

 

package com.knyel.service.impl;import com.knyel.service.HelloKnyel;import org.springframework.stereotype.Service;@Servicepublic class HelloKnyelImpl implements HelloKnyel {    @Override    public String welcome (String name){        System.out.println("welcome");        return "hello knyel";    }}

4.待校验的实体

package com.knyel.dto;import com.fasterxml.jackson.annotation.JsonView;import com.knyel.validator.MyConstraint;import org.hibernate.validator.constraints.NotBlank;import javax.validation.constraints.Past;import java.util.Date;public class User {    public interface UserSimpleView {};    public interface UserDetailView extends UserSimpleView {};    private String id;    @MyConstraint(message = "测试校验器")    private String username;    @NotBlank(message="密码不能为空")    private  String password;    @Past(message = "生日必须是过去的时间")    private Date birthday;    @JsonView(UserSimpleView.class)    public String getUsername (){        return username;    }    public void setUsername (String username){        this.username = username;    }    @JsonView(UserDetailView.class)    public String getPassword (){        return password;    }    public void setPassword (String password){        this.password = password;    }    @JsonView(UserSimpleView.class)    public String getId (){        return id;    }    @JsonView(UserSimpleView.class)    public void setId (String id){        this.id = id;    }    public Date getBirthday (){        return birthday;    }    public void setBirthday (Date birthday){        this.birthday = birthday;    }    @Override    public String toString (){        return "User{" + "id='" + id + '\'' + ", username='" + username + '\'' + ", password='" + password + '\'' + ", birthday=" + birthday + '}';    }}

5.controller

@PutMapping("/{id:\\d+}")    public User update (@Valid @RequestBody User user, BindingResult errors){        if (errors.hasErrors()) {            errors.getAllErrors().stream().forEach((ObjectError error) ->{//                FieldError fieldError=(FieldError) error;//                String message=fieldError.getField()+":"+fieldError.getDefaultMessage();                System.out.println(error.getDefaultMessage());            });        }        System.out.println(user.getId());        System.out.println(user.getUsername());        System.out.println(user.getPassword());        System.out.println(user.getBirthday());        user.setId("1");        return user;    }

执行测试用例后

myvalidator initwelcomeknyel测试校验器1