package com.domain;import java.io.Serializable;public class User implements Serializable {    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;    }}

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.domain.User;@Repository("userValidator")//注解将该对象注释为Spring容器中的一个bean，名字为userValidatorpublic 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) {        // TODO Auto-generated method stub        return User.class.isAssignableFrom(clazz);    }    /**对目标target进行校验，并将校验错误存到errors中*/    @Override    public void validate(Object target, Errors errors) {        // TODO Auto-generated method stub        ValidationUtils.rejectIfEmpty(errors, "loginname", "loginnameError");        ValidationUtils.rejectIfEmpty(errors, "password", "passwordError");        User user = (User)target;        if(user.getLoginname().length() > 10)        {            errors.rejectValue("loginname", null, "loginnameMax");        }                if(user.getPassword() != null && user.getPassword().length() < 6)        {            errors.rejectValue("password", null, "passwordMin");        }    }}

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.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import com.domain.User;import com.validator.UserValidator;@Controllerpublic class UserController{    //注入userValidator    @Autowired    @Qualifier("userValidator")    private UserValidator userValidator;        @RequestMapping(value="/login",method=RequestMethod.POST)    public String login(@ModelAttribute User user,Model model,Errors errors)    {        model.addAttribute("user", user);        //验证        userValidator.validate(user, errors);        if(errors.hasErrors())        {            return "loginForm";        }        return "success";    }        @RequestMapping(value="/{formName}")    public String loginForm(@PathVariable String formName,Model model)    {        User user = new User();        model.addAttribute("user", user);        return formName;//动态页面的跳转，可以是任何页面    }}

             
            
             
             
                 
                      
       
        /WEB-INF/content/
                   
                  
                      
       
        .jsp
                   
              
                     
             
                   
                        
                             
                              
        
         classpath:messages
                          
                     
                    
                    
                    
                
               
                 
              
     

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%>                      
         
         
             
         
         
               
登录页面
    
             
      
                   
        
                         
登录名
                         
          
                                                  
          
                    
                    
                         
密码