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spring mvc3中的addFlashAttribute方法

记得在spring mvc2中,当保存POJO到数据库后,要返回成功页面,如果这个时候要带点信息, 
则要这样: 
Java代码:  
    //第三个参数(UserModel user)默认为绑定对象  
    @RequestMapping(value = "/user/save", method = RequestMethod.POST)  
    public ModelAndView saveUser(HttpServletRequest request, HttpServletResponse response,UserModel user) throws Exception {  
        ModelAndView mv = new ModelAndView("/user/save/result");//默认为forward模式  
//      ModelAndView mv = new ModelAndView("redirect:/user/save/result");//redirect模式  
        mv.addObject("message","保存用户成功!");  
        return mv;  
    }  
 
 
而在spring mvc 3.1后,可以这样 
Java代码:  
@RequestMapping(value = "/user/save", method = RequestMethod.POST)  
public ModelAndView saveUser(UserModel user, RedirectAttributes redirectAttributes) throws Exception {  
    redirectAttributes.addFlashAttribute("message", "保存用户成功!");//使用addFlashAttribute,参数不会出现在url地址栏中  
    return "redirect:/user/save/result";  
}  
 
 
  来个稍微完整点的例子,首先是一个表单,在其中填入一些信息: 
 
Java代码: 
<form:form id="myform" action="saveUserDetails.action" method="POST" commandName="user">  
   <form:input type="text" name="firstName" path="firstName"/>  
   <form:input type="text" name="lastName" path="lastName"/>  
   <form:input type="text" name="email" path="email"/>  
   <input type="submit" value="submit">  
</form:form>  
   
 
   则在controller中,可以这样: 
Java代码:  
       @RequestMapping(value="/saveUserDetails.action", method=RequestMethod.POST)  
public String greetingsAction(@Validated User user,RedirectAttributes redirectAttributes){  
              
               someUserdetailsService.save(user);  
      
               redirectAttributes.addFlashAttribute("firstName", user.getFirstName());  
    redirectAttributes.addFlashAttribute("lastName", user.getLastName())  
    return "redirect:success.html";  
}  
 
 
  success.html: 
<div> 
<h1>Hello ${firstName} ${lastName}. Your details stored in our database.</h1> 
</div><br> 
 
  但如果F5的时候,会发现参数丢失,因为flash scope其实只支持redirect的,所以可以判断下: 
 
Java代码: 
@RequestMapping(value="/success.html", method=RequestMethod.GET)  
    public String successView(HttpServletRequest request){  
        Map<String,?> map = RequestContextUtils.getInputFlashMap(request);   
        if (map!=null)  
           return "success";  
        else return "redirect:someOtherView"; //給出其他提示信息  
补充:软件开发 , Java ,
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