10、数据校验:Validation

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10.1、Spring Validation概述

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在开发中,我们经常遇到参数校验的需求,比如用户注册的时候,要校验用户名不能为空、用户名长度不超过20个字符、手机号是合法的手机号格式等等。如果使用普通方式,我们会把校验的代码和真正的业务处理逻辑耦合在一起,而且如果未来要新增一种校验逻辑也需要在修改多个地方。而spring validation允许通过注解的方式来定义对象校验规则,把校验和业务逻辑分离开,让代码编写更加方便。Spring Validation其实就是对Hibernate Validator进一步的封装,方便在Spring中使用。

在Spring中有多种校验的方式

第一种是通过实现org.springframework.validation.Validator接口,然后在代码中调用这个类

第二种是按照Bean Validation方式来进行校验,即通过注解的方式。

第三种是基于方法实现校验

除此之外,还可以实现自定义校验

10.2、实验一:通过Validator接口实现

第一步 创建子模块 spring6-validator

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第二步 引入相关依赖

<dependencies>
    <dependency>
        <groupId>org.hibernate.validator</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>7.0.5.Final</version>
    </dependency>

    <dependency>
        <groupId>org.glassfish</groupId>
        <artifactId>jakarta.el</artifactId>
        <version>4.0.1</version>
    </dependency>
</dependencies>

第三步 创建实体类,定义属性和方法

package com.atguigu.spring6.validation.method1;

public class Person {
    private String name;
    private int age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

第四步 创建类实现Validator接口,实现接口方法指定校验规则

package com.atguigu.spring6.validation.method1;

import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;

public class PersonValidator implements Validator {

    @Override
    public boolean supports(Class<?> clazz) {
        return Person.class.equals(clazz);
    }

    @Override
    public void validate(Object object, Errors errors) {
        ValidationUtils.rejectIfEmpty(errors, "name", "name.empty");
        Person p = (Person) object;
        if (p.getAge() < 0) {
            errors.rejectValue("age", "error value < 0");
        } else if (p.getAge() > 110) {
            errors.rejectValue("age", "error value too old");
        }
    }
}

上面定义的类,其实就是实现接口中对应的方法,

supports方法用来表示此校验用在哪个类型上,

validate是设置校验逻辑的地点,其中ValidationUtils,是Spring封装的校验工具类,帮助快速实现校验。

第五步 使用上述Validator进行测试

package com.atguigu.spring6.validation.method1;

import org.springframework.validation.BindingResult;
import org.springframework.validation.DataBinder;

public class TestMethod1 {

    public static void main(String[] args) {
        //创建person对象
        Person person = new Person();
        person.setName("lucy");
        person.setAge(-1);
        
        // 创建Person对应的DataBinder
        DataBinder binder = new DataBinder(person);

        // 设置校验
        binder.setValidator(new PersonValidator());

        // 由于Person对象中的属性为空,所以校验不通过
        binder.validate();

        //输出结果
        BindingResult results = binder.getBindingResult();
        System.out.println(results.getAllErrors());
    }
}

10.3、实验二:Bean Validation注解实现

使用Bean Validation校验方式,就是如何将Bean Validation需要使用的javax.validation.ValidatorFactory 和javax.validation.Validator注入到容器中。spring默认有一个实现类LocalValidatorFactoryBean,它实现了上面Bean Validation中的接口,并且也实现了org.springframework.validation.Validator接口。

第一步 创建配置类,配置LocalValidatorFactoryBean

@Configuration
@ComponentScan("com.atguigu.spring6.validation.method2")
public class ValidationConfig {

    @Bean
    public LocalValidatorFactoryBean validator() {
        return new LocalValidatorFactoryBean();
    }
}

第二步 创建实体类,使用注解定义校验规则

package com.atguigu.spring6.validation.method2;

import jakarta.validation.constraints.Max;
import jakarta.validation.constraints.Min;
import jakarta.validation.constraints.NotNull;

public class User {

    @NotNull
    private String name;

    @Min(0)
    @Max(120)
    private int age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

常用注解说明
@NotNull 限制必须不为null
@NotEmpty 只作用于字符串类型,字符串不为空,并且长度不为0
@NotBlank 只作用于字符串类型,字符串不为空,并且trim()后不为空串
@DecimalMax(value) 限制必须为一个不大于指定值的数字
@DecimalMin(value) 限制必须为一个不小于指定值的数字
@Max(value) 限制必须为一个不大于指定值的数字
@Min(value) 限制必须为一个不小于指定值的数字
@Pattern(value) 限制必须符合指定的正则表达式
@Size(max,min) 限制字符长度必须在min到max之间
@Email 验证注解的元素值是Email,也可以通过正则表达式和flag指定自定义的email格式

第三步 使用两种不同的校验器实现

(1)使用jakarta.validation.Validator校验

package com.atguigu.spring6.validation.method2;

import jakarta.validation.ConstraintViolation;
import jakarta.validation.Validator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.Set;

@Service
public class MyService1 {

    @Autowired
    private Validator validator;

    public  boolean validator(User user){
        Set<ConstraintViolation<User>> sets =  validator.validate(user);
        return sets.isEmpty();
    }

}

(2)使用org.springframework.validation.Validator校验

package com.atguigu.spring6.validation.method2;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.validation.BindException;
import org.springframework.validation.Validator;

@Service
public class MyService2 {

    @Autowired
    private Validator validator;

    public boolean validaPersonByValidator(User user) {
        BindException bindException = new BindException(user, user.getName());
        validator.validate(user, bindException);
        return bindException.hasErrors();
    }
}

第四步 测试

package com.atguigu.spring6.validation.method2;

import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class TestMethod2 {

    @Test
    public void testMyService1() {
        ApplicationContext context = new AnnotationConfigApplicationContext(ValidationConfig.class);
        MyService1 myService = context.getBean(MyService1.class);
        User user = new User();
        user.setAge(-1);
        boolean validator = myService.validator(user);
        System.out.println(validator);
    }

    @Test
    public void testMyService2() {
        ApplicationContext context = new AnnotationConfigApplicationContext(ValidationConfig.class);
        MyService2 myService = context.getBean(MyService2.class);
        User user = new User();
        user.setName("lucy");
        user.setAge(130);
        user.setAge(-1);
        boolean validator = myService.validaPersonByValidator(user);
        System.out.println(validator);
    }
}

10.4、实验三:基于方法实现校验

第一步 创建配置类,配置MethodValidationPostProcessor

package com.atguigu.spring6.validation.method3;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;

@Configuration
@ComponentScan("com.atguigu.spring6.validation.method3")
public class ValidationConfig {

    @Bean
    public MethodValidationPostProcessor validationPostProcessor() {
        return new MethodValidationPostProcessor();
    }
}

第二步 创建实体类,使用注解设置校验规则

package com.atguigu.spring6.validation.method3;

import jakarta.validation.constraints.*;

public class User {

    @NotNull
    private String name;

    @Min(0)
    @Max(120)
    private int age;

    @Pattern(regexp = "^1(3|4|5|7|8)\\d{9}$",message = "手机号码格式错误")
    @NotBlank(message = "手机号码不能为空")
    private String phone;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
}

第三步 定义Service类,通过注解操作对象

package com.atguigu.spring6.validation.method3;

import jakarta.validation.Valid;
import jakarta.validation.constraints.NotNull;
import org.springframework.stereotype.Service;
import org.springframework.validation.annotation.Validated;

@Service
@Validated
public class MyService {
    
    public String testParams(@NotNull @Valid User user) {
        return user.toString();
    }

}

第四步 测试

package com.atguigu.spring6.validation.method3;

import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class TestMethod3 {

    @Test
    public void testMyService1() {
        ApplicationContext context = new AnnotationConfigApplicationContext(ValidationConfig.class);
        MyService myService = context.getBean(MyService.class);
        User user = new User();
        user.setAge(-1);
        myService.testParams(user);
    }
}

10.5、实验四:实现自定义校验

第一步 自定义校验注解

package com.atguigu.spring6.validation.method4;

import jakarta.validation.Constraint;
import jakarta.validation.Payload;
import java.lang.annotation.*;

@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Constraint(validatedBy = {CannotBlankValidator.class})
public @interface CannotBlank {
    //默认错误消息
    String message() default "不能包含空格";

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

    //负载
    Class<? extends Payload>[] payload() default {};

    //指定多个时使用
    @Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @interface List {
        CannotBlank[] value();
    }
}

第二步 编写真正的校验类

package com.atguigu.spring6.validation.method4;

import jakarta.validation.ConstraintValidator;
import jakarta.validation.ConstraintValidatorContext;

public class CannotBlankValidator implements ConstraintValidator<CannotBlank, String> {

        @Override
        public void initialize(CannotBlank constraintAnnotation) {
        }

        @Override
        public boolean isValid(String value, ConstraintValidatorContext context) {
                //null时不进行校验
                if (value != null && value.contains(" ")) {
                        //获取默认提示信息
                        String defaultConstraintMessageTemplate = context.getDefaultConstraintMessageTemplate();
                        System.out.println("default message :" + defaultConstraintMessageTemplate);
                        //禁用默认提示信息
                        context.disableDefaultConstraintViolation();
                        //设置提示语
                        context.buildConstraintViolationWithTemplate("can not contains blank").addConstraintViolation();
                        return false;
                }
                return true;
        }
}