Spring MVC--RequestMapping

1. 窄化请求

在类上用注解 @RequestMapping 相当于在加一层目录  访问时 ： 项目名/user/.......

//窄化请求
@RequestMapping("user")
public class UserControoler {}

2. 参数绑定

@ResponseBody
@RequestMapping("/findById.action")   
public String findById(HttpServletRequest request,@RequestParam(name = "uid",required = true) Integer id){ // 必须要有参数uid
  return "***";  
}

2.2 提交方式

@RequestMapping
　　(
　　　　path = "/queryAll.action",
　　　　method = {RequestMethod.POST,RequestMethod.GET}，
     params = {"uid=1"}
  )

3. controller方法返回值 ModelandView (最常用)   String    void 

 public ModelAndView test1(){ // 最常用，最方便

    　ModelAndView modelAndView = new ModelAndView();
      modelAndView.addObject("msg","你好");
      modelAndView.setViewName("../index.jsp");
   
      return modelAndView;
}

1   public String test2(Model model){ //model将数据保存到了request域中了，所以转发数据共享，重定向时，是两次请求，数据不共享
2     　　model.addAttribute("msg","你好");
3     　　return "forward:../index.jsp";
4     　　return "redirect:../index.jsp"
5  }  

    public void test3(HttpServletRequest request, HttpServletResponse response){
        request.setAttribute("msg","日月星辰");
        request.getRequestDispatcher("../index.jsp").forward(request,response);
    }

5. 文件上传

springmvc.xml -- 解析fileUpload组件 id 必须为：multipartResolver

  <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>

web.jsp

    <form method="post" enctype="multipart/form-data" action="user/upload.action">
        <input type="file" name="file">
        <input type="submit" value="上传">
    </form>

Controller Class @RequestMapping("user") // 窄化请求

    @RequestMapping("/upload.action")
    @ResponseBody
    public String upload(MultipartFile file) throws IOException {
        //文件名
        String originalFilename = file.getOriginalFilename();
        String uuid = UUID.randomUUID().toString().replace("-", ""); // 32位字符用不重复
        int i = originalFilename.lastIndexOf(".");
        String suffix = originalFilename.substring(i);

        //页面的file的name属性值
        String name = file.getName();
        System.out.println(originalFilename);
        System.out.println(name);
        File file1 = new File("E:\upload\"+uuid+suffix);
        file.transferTo(file1);
        return "上传中";
    }