Spring MVC 使用Validator接口完成数据校验

我会带着你远行 2022-05-14 20:42 168阅读 0赞

**Spring MVC 使用Validator接口完成数据校验**

**创建loginForm.jsp**

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <%@taglib prefix= "form" uri= "http://www.springframework.org/tags/form" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>测试Validator接口验证</title>
    </head>
    <body>
    <h3>登录页面</h3>
    
    <form:form modelAttribute="user" method="post" action="login" >
    	<table>
    		<tr>
    			<td>登录名:</td>
    			<td><form:input path="loginname"/></td>
    			
    			<td><form:errors path="loginname" cssStyle= "color:red"/></td>
    		</tr>
    		<tr>
    			<td>密码:</td>
    			<td><form:input path="password"/></td>
    			
    			<td><form:errors path="password" cssStyle= "color:red"/></td>
    		</tr>
    		<tr>
    			<td><input type="submit" value="提交"/></td>
    		</tr>
    	</table>
    </form:form>
    </body>
    </html>

**创建success.jsp**

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>测试ConversionService</title>
    </head>
    <body>
    登录名：${requestScope.user.loginname }<br>
    登录名：${requestScope.user.password }<br>
    </body>
    </html>

**配置springmvc-config.xml**

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:p="http://www.springframework.org/schema/p"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:mvc="http://www.springframework.org/schema/mvc"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
            http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
    
    <mvc:annotation-driven />
    
    <context:component-scan base-package="com.*" />
    
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    	<property name="prefix" value="/WEB-INF/view/"></property>
    	<property name="suffix" value=".jsp" />
    </bean>
    </beans>

**创建User**

package com.po;
    public class User {
    	private String loginname;
    	private String password;
    	public String getLoginname() {
    		return loginname;
    	}
    	public void setLoginname(String loginname) {
    		this.loginname = loginname;
    	}
    	public String getPassword() {
    		return password;
    	}
    	public void setPassword(String password) {
    		this.password = password;
    	}
    	@Override
    	public String toString() {
    		return "User [loginname=" + loginname + ", password=" + password + "]";
    	}
    }

**创建UserValidator**

package com.validator;
    import org.springframework.stereotype.Repository;
    import org.springframework.validation.Errors;
    import org.springframework.validation.ValidationUtils;
    import org.springframework.validation.Validator;
    
    import com.po.User;
    // 实现Spring的Validator接口
    @Repository("userValidator")
    public class UserValidator implements Validator {
    
    	// 该校验器能够对clazz类型的对象进行校验。
    	@Override
    	public boolean supports(Class<?> clazz) {
    		// User指定的 Class 参数所表示的类或接口是否相同，或是否是其超类或超接口。
    		return User.class.isAssignableFrom(clazz);
    	}
    
    	// 对目标类target进行校验，并将校验错误记录在errors当中
    	@Override
    	public void validate(Object target, Errors errors) {
    		/**
    		使用ValidationUtils中的一个静态方法rejectIfEmpty()来对loginname属性进行校验，
    		假若'loginname'属性是 null 或者空字符串的话，就拒绝验证通过 。
    		*/
    		ValidationUtils.rejectIfEmpty(errors, "loginname", null, "登录名不能为空");  
    		ValidationUtils.rejectIfEmpty(errors, "password", null, "密码不能为空");  
    		User user = (User)target;
    		if(user.getLoginname().length() > 10){
    			// 使用Errors的rejectValue方法验证
    			errors.rejectValue("loginname", null, "用户名不能超过10个字符");
    		}
    		if(user.getPassword() != null 
    				&& !user.getPassword().equals("") 
    				&& user.getPassword().length() < 6){
    			errors.rejectValue("password", null, "密码不能小于6位");
    		}
    	}
    }

**创建UserController**

package com.controller;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Qualifier;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.validation.Errors;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    import com.po.User;
    import com.validator.UserValidator;
    @Controller
    public class UserController {
    	// 注入UserValidator对象
    		@Autowired
    		@Qualifier("userValidator")
    		private UserValidator userValidator;
    		
    		@RequestMapping(value="/loginForm")
    		 public String loginForm(Model model){
    			User user = new User();
    			model.addAttribute("user",user);
    			// 跳转到登录页面
    			return "loginForm";
    		}
    		 
    		@RequestMapping(value="/login")
    		 public String login(
    				 @ModelAttribute User user,
    				 Model model,
    				 Errors errors) {
    			 System.out.println(user);
    			 model.addAttribute("user", user);
    			 // 调用userValidator的验证方法
    			 userValidator.validate(user, errors);
    			 // 如果验证不通过跳转到loginForm视图
    			 if(errors.hasErrors()){
    				 return "loginForm";
    			 }
    		     return "success";
    		 }
    }

**启动Tomcat访问如下地址**

[http://localhost:8080/jackson/loginForm][http_localhost_8080_jackson_loginForm]

![70][]

![70 1][]

![70 2][]

![70 3][]

[http_localhost_8080_jackson_loginForm]: http://localhost:8080/jackson/loginForm
[70]: /images/20220515/9b9b2dd55ad54e9899a6fcd2afffeea1.png
[70 1]: /images/20220515/993cf9348b2f43a08a3ab2c64d0bc15a.png
[70 2]: /images/20220515/e692a9d21a7a4c219798f6d9ba54cbab.png
[70 3]: /images/20220515/3169ba1432c14f43836a31609751b36d.png