java文件上传与接收处理

文件上传

//使用的hutool工具包的HttpUtil 自动识别参数是否有文件 修改请求类型为 multipart/form-data

   private static String request(String ip, File file) {
        String result = "";
        String errorMsg = "";
        try {
            HashMap<String, Object> paramMap = new HashMap<>();
            paramMap.put("type", "update");
            if (null != file) {
                paramMap.put("file", file);
            }
            result = HttpUtil.post(ip + "/server", paramMap);
        } catch (Exception e) {
            errorMsg = e.getMessage();
        }
        return StrUtil.isEmpty(errorMsg) ? result : errorMsg;
    }

文件接收端

引入依赖
<dependency>
			<groupId>commons-fileupload</groupId>
			<artifactId>commons-fileupload</artifactId>
			<version>1.5</version>
		</dependency>



    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
           MultipartHttpServletRequest multiRequest;
            //ContentType为application/json 的 请求参数取值
            String type = request.getParameter("type");
            // ContentType为 multipart/form-data 时转换请求对象
         
            ServletContext context = request.getSession().getServletContext();
            //将当前上下文初始化给  CommonsMultipartResolver （多部分解析器）
            MultipartResolver resolver = new CommonsMultipartResolver(context);
            //是否是文件上传
            boolean isUpload = false;
            
            if (resolver.isMultipart(request)) {
                multiRequest = resolver.resolveMultipart(request);
                //解析request的 请求参数取值
                type = multiRequest.getParameter("type");
                isUpload = true;
            }
            
             MultipartFile file =  multiRequest.getFile("file");
             //文件的其他操作
            
            response.setContentType("application/json");
            response.setCharacterEncoding("UTF-8");

         
            
            response.getOutputStream().write("OK".getBytes(Constants.DEFAULT_CHARSET));
        } catch (Exception e) {
            response.getWriter().write(e.getMessage());
        }
    }