Java Web文件上传

        try {
            // 判断enctype属性是否为multipart/form-data
            boolean isMultipart = ServletFileUpload.isMultipartContent(request);
            if (!isMultipart) {// 不是文件上传，用传统方法获取数据
                // String userId = request.getParameter("userId");等
                return;
            }

            // 为multipart/form-data
            int maxMemorySize = 1024 * 1000 * 50;// 50MB
            int maxRequestSize = 1024 * 1000 * 100;// 100MB
            String projAbsolutePath = request.getRealPath("");
            String uploadRelativeDir = "upload/apk/";
            String uploadTmpRelativeDir = uploadRelativeDir + "/tmp/";
            File uploadDirObj = new File(projAbsolutePath + uploadRelativeDir);
            if (!uploadDirObj.exists()) {
                uploadDirObj.mkdirs();
            }
            File uploadTmpDirObj = new File(projAbsolutePath + uploadTmpRelativeDir);
            if (!uploadTmpDirObj.exists()) {
                uploadTmpDirObj.mkdirs();
            }

            // Create a factory for disk-based file items
            DiskFileItemFactory factory = new DiskFileItemFactory();

            // 当上传文件太大时，因为虚拟机能使用的内存是有限的，所以此时要通过临时文件来实现上传文件的保存
            // 此方法是设置是否使用临时文件的临界值（单位：字节）
            factory.setSizeThreshold(maxMemorySize);
            // 与上一个结合使用，设置临时文件的路径（绝对路径）
            factory.setRepository(uploadTmpDirObj);

            // Create a new file upload handler
            ServletFileUpload upload = new ServletFileUpload(factory);

            // 解决上传文件名的中文乱码,tomcat8不需要了
            // upload.setHeaderEncoding("UTF-8");

            // 设置上传内容的大小限制（单位：字节）
            upload.setSizeMax(maxRequestSize);

            // Parse the request
            List<FileItem> items = upload.parseRequest(request);
            Iterator<?> iter = items.iterator();
            String fieldName = null;
            FileItem item = null;
            String fileName = null;
            String version = null;
            while (iter.hasNext()) {
                item = (FileItem) iter.next();
                fieldName = item.getFieldName();
                if (item.isFormField()) {// 普通表单字段，版本信息
                    version = item.getString();
                    System.out.println(fieldName + " " + version);
                } else {// 文件字段
                    fileName = item.getName();
                    if (!fileName.endsWith("apk")) {// 不是apk文件
                        System.out.println("不是apk文件");
                        return;
                    }
                    fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
                    String contentType = item.getContentType();
                    boolean isInMemory = item.isInMemory();
                    long sizeInBytes = item.getSize();
                    System.out.println(fileName + " " + contentType + " " + isInMemory + " " + sizeInBytes);
                    item.write(new File(uploadDirObj, fileName));
                }
            }
            apkInfoMapper.insertVersionInfo(version,
                    new SimpleDateFormat("yy-MM-dd HH:mm:ss").format(System.currentTimeMillis()),
                    (uploadRelativeDir + fileName));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }