spring MVC 3.1 forword/redirect
spring mvc 如何请求转发和重定向呢？往下看：
由于这部分内容简单，一带而过了。
<wbr></wbr>
1.请求转发：
<wbr><wbr>（1）返回<span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; background-color:rgb(250,250,250)">ModelAndView</span><span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; background-color:rgb(250,250,250)"><wbr>：</wbr></span></wbr></wbr>
public ModelAndView testForward(ModelAndView <wbr><wbr>model,@RequestParam(value="id",defaultValue="1",required=false)Long id){<br><wbr><wbr><wbr>User u = getBaseService().get(User.class, id);<br><wbr><wbr><wbr>model.addObject("user", u);<br><span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; color:rgb(255,0,0)"><wbr><wbr><wbr>model.setViewName("forward:index.jsp");</wbr></wbr></wbr></span><br><wbr><wbr><wbr>return model;<br> }</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
<wbr>如上代码，如果返回modelAndView 则可以如红色标注,添加forward即可，若想重定向，可把forward替换成redirect便可达到目的。</wbr>
<wbr></wbr>
（2）返回字符串
<wbr></wbr>
<wbr><wbr>public String testForward(){<br><br><span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; color:rgb(255,0,0)"><wbr><wbr><wbr><wbr>return "forward:/index.action";</wbr></wbr></wbr></wbr></span><br><wbr><wbr>}</wbr></wbr></wbr></wbr>
<wbr>如上代码红色部分。</wbr>
<wbr></wbr>
2.请求重定向
<wbr>对于请求转发可以分为：1.带参数 2.不带参数</wbr>
<wbr></wbr>
（1）带参数：
<wbr></wbr>
- @RequestMapping(value="/redirect",method=RequestMethod.GET)<wbr><wbr></wbr></wbr>
- public<wbr>String<wbr>testRedirect(RedirectAttributes<wbr>attr){<wbr><wbr></wbr></wbr></wbr></wbr></wbr>
- <wbr><wbr><wbr><wbr><wbr>attr.addAttribute(<span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:blue">"a"</span>,<wbr><span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:blue">"a"</span>);<wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
- <wbr><wbr><wbr><wbr><wbr>attr.addFlashAttribute(<span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:blue">"b"</span>,<wbr><span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:blue">"b"</span>);<wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
- <wbr><wbr><wbr><wbr><wbr><span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:rgb(127,0,85)"><strong>return</strong></span><wbr><span style="word-wrap:normal; word-break:normal; line-height:17.600000381469727px; color:blue">"redirect:/index.action"</span>;<wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
- }<wbr><wbr></wbr></wbr>
<wbr></wbr>
<wbr>带参数可使用RedirectAttributes参数进行传递：</wbr>
<wbr><wbr><wbr><span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; color:rgb(255,0,0)"><wbr>注意</wbr></span>：<span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; background-color:rgb(255,255,153)">1.使用RedirectAttributes的addAttribute方法传递参数会跟随在URL后面 ，如上代码即为http:/index.action?a=a</span></wbr></wbr></wbr>
<wbr><wbr><wbr><wbr><wbr><wbr><wbr>2.使用addFlashAttribute不会跟随在URL后面，会把该参数值暂时保存于session，待重定向url获取该参数后从session中移除，这里的redirect必须是方法映射路径，jsp无效。你会发现redirect后的jsp页面中b只会出现一次，刷新后b再也不会出现了，这验证了上面说的，b被访问后就会从session中移除。对于重复提交可以使用此来完成.</wbr></wbr></wbr></wbr></wbr></wbr></wbr>
<wbr></wbr>
<wbr><wbr><wbr>另外，如果使用了RedirectAttributes作为参数，但是没有进行redirect呢？这种情况下不会将RedirectAttributes参数传递过去，默认传forward对应的model，官方的建议是：</wbr></wbr></wbr>
p:ignoreDefaultModelOnRedi<wbr>rect="true" /></wbr>
<wbr>设置下<span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; background-color:rgb(250,250,250)">RequestMappingHandlerAda<wbr>pter 的</wbr></span><span style="word-wrap:normal; word-break:normal; line-height:21.600000381469727px; background-color:rgb(250,250,250)">ignoreDefaultModelOnRedi<wbr>rect属性,这样可以提高效率，避免不必要的检索。</wbr></span></wbr>
<wbr></wbr>
<wbr></wbr>
（2）无参数
<wbr></wbr>
public String testRedirect(){
return "redirect:/index.action";
}