数据校验一（利用Spring自带的validation校验框架）

实现了Validator接口，前端页面使用标签显示属性的错误信息

1.javaBean

package com.bean;

public class User {
 private String username;
 private String password;
 public String getUsername() {
  return username;
 }
 public void setUsername(String username) {
  this.username = username;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 }

}

2.前端登陆页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri= "http://www.springframework.org/tags/form"  prefix="form" %>

登录页面

 
  
   
   
   
   
  
  
   
   
   
   
  
  
   
  
 

登录名:
密码:

3.MyValidator类，实现了Validator接口

package com.validator;

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

import com.bean.User;

@Component("validator")
public class MyValidator implements Validator {

 @Override
 public boolean supports(Class clazz) {
  // TODO Auto-generated method stub
  return User.class.isAssignableFrom(clazz);
 }

 @Override
 public void validate(Object target, Errors errors) {
  // TODO Auto-generated method stub
  User user = (User)target;
  ValidationUtils.rejectIfEmpty(errors, "username", "U404", "用户名不能为空");
  ValidationUtils.rejectIfEmpty(errors, "password", null, "密码不能为空");
  
  if(user.getUsername().length() > 10){
   errors.rejectValue("username", "U405", "用户名长度不能超过10个字符");
  }
  
  if(user.getPassword().length() < 6){
   errors.rejectValue("password", null, "密码长度不能小于6个字符");
  }
 }
 

}

4.Controller类

package com.controller;

import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.validation.Errors;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import com.bean.User;
import com.validator.MyValidator;

@Controller
public class UserController {
 @Autowired
 @Resource
 private MyValidator validator;
 @RequestMapping("/{login}")
 public String login(@PathVariable String login, ModelMap mm){
  mm.addAttribute("user", new User());
  return login;
 }
 
 @RequestMapping("/tologin")
 //在需要校验的属性前面加@Validated
 //BindingResult属性必须要放在@Validated注解属性的后面，否则spring会在校验不通过时直接抛出异常
 public String tologin(@Validated User user, BindingResult result){
  if(result.hasErrors()){
   return "login";
  }
  
  return "success";
 }
 @InitBinder
 public void initBinder(WebDataBinder binder){
  binder.setValidator(validator);
 }
 /*@RequestMapping("/tologin")
 //在需要校验的属性前面加@Validated
 //Errors属性必须要放在@Validated注解属性的后面
 public String tologin(@Validated User user, Errors errors){
  validator.validate(user, errors);
  if(errors.hasErrors()){
   return "login";
  }
  return "success";
 }*/

}

上面两种@RequestMapping("/tologin")映射的作用效果一样

5.配置文件：

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd    
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.3.xsd">
       
   
   
   
   
   
   
               class="org.springframework.web.servlet.view.InternalResourceViewResolver">
       
       
            /WEB-INF/jsp/
       
       
       
            .jsp