Android HttpURLConnection上传图片至Servlet端指定目录

客户端（核心代码）：

/**
 * 文件上传
 *
 * @param urlStr 接口路径
 * @param filePath 本地图片路径
 * @return
 */
public static String formUpload(String urlStr, String filePath) {
    String rsp = "";
    HttpURLConnection conn = null;
    String BOUNDARY = "|"; // request头和上传文件内容分隔符
    try {
        URL url = new URL(urlStr);
        conn = (HttpURLConnection) url.openConnection();
        conn.setConnectTimeout(5000);
        conn.setReadTimeout(30000);
        conn.setDoOutput(true);
        conn.setDoInput(true);
        conn.setUseCaches(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("User-Agent",
                "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.6)");
        conn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + BOUNDARY);

        OutputStream out = new DataOutputStream(conn.getOutputStream());
        File file = new File(filePath);
        String filename = file.getName();
        String contentType = "";
        if (filename.endsWith(".png")) {
            contentType = "image/png";
        }
        if (filename.endsWith(".jpg")) {
            contentType = "image/jpg";
        }
        if (filename.endsWith(".gif")) {
            contentType = "image/gif";
        }
        if (filename.endsWith(".bmp")) {
            contentType = "image/bmp";
        }
        if (contentType == null || contentType.equals("")) {
            contentType = "application/octet-stream";
        }
        StringBuffer strBuf = new StringBuffer();
        strBuf.append("\r\n").append("--").append(BOUNDARY).append("\r\n");
        strBuf.append("Content-Disposition: form-data; name=\"" + filePath
                + "\"; filename=\"" + filename + "\"\r\n");
        strBuf.append("Content-Type:" + contentType + "\r\n\r\n");
        out.write(strBuf.toString().getBytes());
        DataInputStream in = new DataInputStream(new FileInputStream(file));
        int bytes = 0;
        byte[] bufferOut = new byte[1024];
        while ((bytes = in.read(bufferOut)) != -1) {
            out.write(bufferOut, 0, bytes);
        }
        in.close();
        byte[] endData = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();
        out.write(endData);
        out.flush();
        out.close();

        // 读取返回数据
        StringBuffer buffer = new StringBuffer();
        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "utf-8"));
        String line = null;
        while ((line = reader.readLine()) != null) {
            buffer.append(line).append("\n");
        }
        rsp = buffer.toString();
        reader.close();
        reader = null;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (conn != null) {
            conn.disconnect();
            conn = null;
        }
    }
    return rsp;
}

服务端（核心代码）：

public class upload extends HttpServlet {

    public upload() {
        super();
    }

    public void destroy() {
        super.destroy();
    }

    /**
     * The doGet method of the servlet.

     * This method is called when a form has its tag value method equals to get.
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println(
                "");
        out.println("");
        out.println("  ");
        out.println("  ");
        out.print("    This is ");
        out.print(this.getClass());
        out.println(", using the GET method");
        out.println("  ");
        out.println("");
        out.flush();
        out.close();
    }

    /**
     * The doPost method of the servlet.

     * This method is called when a form has its tag value method equals to
     * post.
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    @SuppressWarnings("deprecation")
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8"); // 设置编码
        // 获得磁盘文件条目工厂
        DiskFileItemFactory factory = new DiskFileItemFactory();
        // 设定文件需要上传到的路径
        File file = new File("E://WebSite");
        if (!file.exists()) {
            file.mkdirs();
        }
        factory.setRepository(file);
        // 设置 缓存的大小
        factory.setSizeThreshold(1024 * 1024);
        // 文件上传处理
        ServletFileUpload upload = new ServletFileUpload(factory);
        try {
            // 可以上传多个文件
            List list = (List) upload.parseRequest(request);
            for (FileItem item : list) {
                // 获取属性名字
                String name = item.getFieldName();
                // 如果获取的 表单信息是普通的 文本 信息
                if (item.isFormField()) {
                    // 获取用户具体输入的字符串,因为表单提交过来的是 字符串类型的
                    String value = item.getString();
                    request.setAttribute(name, value);
                } else {
                    // 获取路径名
                    String value = item.getName();
                    // 索引到最后一个反斜杠
                    int start = value.lastIndexOf("\\");
                    // 截取 上传文件的 字符串名字，加1是 去掉反斜杠，
                    String filename = value.substring(start + 1);
                    request.setAttribute(name, filename);
                    // 写到磁盘上
                    item.write(new File("E://WebSite", filename));// 第三方提供的
                    System.out.println("上传成功：" + filename);
                    response.getWriter().print(filename);// 将路径返回给客户端
                }
            }
        } catch (Exception e) {
            System.out.println("上传失败");
            e.printStackTrace();
        }
    }

    /**
     * Initialization of the servlet.

     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }
}
 

注对于commons-fileupload-1.4.jar和commons-io-1.4.jar而言，不仅仅需要在servlet工程中住进来，还要在本地的Tomcat/lib目录下面进行追加。