java开发之基于Validator接口的SpringMVC数据校验方式

基于 Validator 接口的⽅式需要自定义 Validator 验证器，每⼀条数据的验证规则需要开发者⼿动完成，使⽤ Annotation JSR - 303 标准则不需要⾃定义验证器，通过注解的方式可以直接在实体类中添加每个属性的验证规则，这种方式更加方便，实际开发中推荐使用。

1.定义实体类Account

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									package entity;

									import lombok.Data;

									@Data

									public class Account {

									    private String name;

									    private String password;

									}

2.自定义验证器 AccountValidator，实现 Validator 接口

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									package validator;

									import entity.Account;

									import org.springframework.validation.Errors;

									import org.springframework.validation.ValidationUtils;

									import org.springframework.validation.Validator;

									public class AccountValidator implements Validator {

									    @Override

									    public boolean supports(Class<?> aClass) {

									        return Account.class.equals(aClass);

									    }

									    @Override

									    public void validate(Object o, Errors errors) {

									        ValidationUtils.rejectIfEmpty(errors,"name",null,"姓名不能为空");

									        ValidationUtils.rejectIfEmpty(errors,"password",null,"密码不能为空");

									    }

									}

Validator中有两个方法， supports是判断传入是否为目标类，如果是的话则进行下一步，数据验证的操作。

3.控制器

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									package Mycontroller; 

									import entity.Account;

									import entity.Person;

									import org.springframework.stereotype.Controller;

									import org.springframework.ui.Model;

									import org.springframework.validation.BindingResult;

									import org.springframework.validation.annotation.Validated;

									import org.springframework.web.bind.annotation.GetMapping;

									import org.springframework.web.bind.annotation.PostMapping;

									import org.springframework.web.bind.annotation.RequestMapping;

									import org.springframework.web.servlet.ModelAndView;

									import javax.validation.Valid;

									@Controller

									@RequestMapping("/validator")

									public class ValidatorHandler {

									    @GetMapping("/login")

									    public String login(Model model){

									        model.addAttribute("account",new Account());

									        return "login";

									    }

									    @PostMapping("/login")

									    public String login(@Validated Account account, BindingResult bindingResult){

									        if(bindingResult.hasErrors()){

									            return "login";

									        }

									        return "index";

									    }

4. springmvc.xml 配置验证器

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									<bean id="accountValidator" class="com.southwind.validator.AccountValidator">

									</bean>

									<mvc:annotation-driven validator="accountValidator"></mvc:annotation-driven>

5.jsp文件

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									<%@ page contentType="text/html;charset=UTF-8" language="java" %>

									<%@ page isELIgnored="false" %>

									<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>

									<html>

									<head>

									    <title>Title</title>

									</head>

									<body>

									    <form:form modelAttribute="account" action="/validator/login" method="post">

									        姓名:<form:input path="name"></form:input><form:errors path="name"></form:errors><br>

									        密码:<form:input path="password"></form:input><form:errors path="password"></form:errors><br>

									        <input type="submit" value="登录">

									    </form:form>

									</body>

									</html>