上传文件前台后台必备的条件

前台：

1.表单提交方式为post

2.有文件上传输入框<input type="file" name="xxx"这里的name是什么，后台接收的MutipartFile xxx ，名称一致

3.form表单中不许添加entype="mutipart/form-data"

后台

1.导jar包

commons-io.jar

commons-fileupload.jar

2.配置文件上传解析器   （  id   必须为mutipartResolver）

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 设定默认编码 -->
        <property name="defaultEncoding" value="UTF-8"/>
    </bean>

3.用MutipartFile接收参数，参数名称和input中的name值一致

以下是文件的上传和修改

 @RequestMapping("/addProduct.do")
    public String addProduct(Product product, MultipartFile file, HttpSession session) throws IOException {
       // System.out.println(product.getName());
        String path=session.getServletContext().getRealPath("/productImg");
        File file1=new File(path);
        if(!file1.exists()){
            file1.mkdirs();
        }
        String fileName=System.currentTimeMillis()+"-"+file.getOriginalFilename();
        System.out.println(fileName);
        file.transferTo(new File(path+File.separator+fileName));
        product.setId(IdUtils.getUUID());
        product.setImgurl("/productImg/"+fileName);
        adminService.addProduct(product);
        return "/admin/listProduct.do";
    }

 @RequestMapping("/editProduct.do")
    public String editProduct(Product product,HttpSession session,MultipartFile file) throws IOException {
        System.out.println(file.getOriginalFilename());
        if(!file.isEmpty()){
            String path=session.getServletContext().getRealPath("/productImg");
            //String path="D:/idea-workspace/bookStore/src/main/webapp/productImg";
            Product product1=productService.findProductById(product.getId());
            File file1=new File(path,file.getOriginalFilename());
            if(file1.exists()){
                file1.delete();
            }
            String fileName = System.currentTimeMillis() + "-" + file.getOriginalFilename();
            product.setImgurl("/productImg/"+fileName);
            System.out.println(fileName);
           file.transferTo(new File(path,fileName));
        }
        adminService.editProduct(product);
        return "/admin/listProduct.do";
    }