http 上传文件的方法

/** 
         * 
         * sendMultipartDataToHttpServer 
         * 使用post方法请求web服务器，并且当表单数据为：multipart/form-data格式。http请求使用{@link#HTTP_ENCODING}编码<br/>
         * 返回json数据，支持文件名中文上传和多文件上传，不支持断点上传，要正确编码服务端返回{@link#HTTP_ENCODING}编码<br/> 
         * @param url 
         * @param files 文件表单域 
         * @param fields 非文件表单域 
         * @return JSONObject 
         * @throws Exception 
         * @exception 
         * @since  1.0.0
 
         */ 
        public static JSONObject sendMultipartDataToHttpServer(URL url, 
                       final Map<String, File> files, final Map<String, String> fields,
                         final UsernamePasswordCredentials credentials) throws IOException ,JSONException,Exception{
                 URL myurl = null;
                 String queryString = "";

                 // 其他的表单域
                 if (fields != null) {
                         for (Map.Entry<String, String> entry : fields.entrySet()) { 
                                queryString += "&" + URLEncoder.encode(entry.getKey(),HTTP_ENCODING) + "=" 
                                               + URLEncoder.encode(entry.getValue(), HTTP_ENCODING);
                         }
                 }
                 if (!queryString.equals("")) {
                         queryString = queryString.replaceFirst("&", "?");
                 } else {
                 }
                 myurl = new URL(url.getProtocol(), url.getHost(),url.getPort(), url.getPath() + queryString);
                HttpURLConnection conn = (HttpURLConnection) myurl.openConnection();
                conn.setConnectTimeout(UPLOAD_REQUEST_TIMEOUT);
                 conn.setRequestMethod(HTTP_METHOD.POST.toString());
                 conn.setDoInput(true);
                conn.setDoOutput(true); 
                conn.setUseCaches(false);

                 String boundary = "laohuidi_" + java.util.UUID.randomUUID().toString() + "_laohuidi";
                 conn.setRequestProperty(
                                                 "Accept",
 
                                                "image/gif,image/x-xbitmap,image/jpeg,image/pjpeg,application/vnd.ms-excel,application/vnd.ms-powerpoint,application/msword,application/x-shockwave-flash,application/x-quickviewplus,*/*");
 
                conn.setRequestProperty("keep-alive", "300"); 
                conn.setRequestProperty(
                                                "user-agent",
 
                                                "Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6 GTB6");
                 conn.setRequestProperty("accept-language", "zh-cn,zh;q=0.5");
                 conn.setRequestProperty("Connection", "Keep-Alive");
                 conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+ boundary);
                 DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
                 // 乱码问题 可以试下 PrintWriter out = new PrintWriter(new
                 // OutputStreamWriter(connection.getOutputStream(),"utf-8"));
                 dos = new DataOutputStream(conn.getOutputStream());
                int bytesRead, bytesAvailable, bufferSize;
                 byte[] buffer;
                 int maxBufferSize = IO_BUFFER_SIZE;
                 String tem = "";
                 if(files!=null)
                 for (Map.Entry<String, File> entry : files.entrySet()){
 
                        // 分隔符开头
                         dos.writeBytes(TWO_HYPHENS + boundary + LINEND);
                         // create a buffer of maximum size
                         FileInputStream fileInputStream = new FileInputStream(entry.getValue());
                         bytesAvailable = fileInputStream.available();
                         bufferSize = Math.min(bytesAvailable, maxBufferSize);
                         buffer = new byte[bufferSize];
                        // read file and write it into form...
                         bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                         tem = entry.getValue().getName();
                         dos.writeBytes("Content-Disposition:form-data;name=\""+entry.getKey()+"\";"+ "filename=\"");
                         dos.writeUTF(tem);// 中文的文件名使用这里
                         dos.writeBytes("\"" + LINEND);
                         dos.writeBytes("Content-Type:image/jpg" + LINEND + LINEND);//类型的判断暂时不处理 
                        while (bytesRead > 0) {
                                 dos.write(buffer, 0, bufferSize);
                          　　    bytesAvailable = fileInputStream.available();
                                 bufferSize = Math.min(bytesAvailable, maxBufferSize);
                                 bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                         }
                         // close streams
                         fileInputStream.close();
                         dos.writeBytes(LINEND);
                 }
                 // http 结束符
                 dos.writeBytes(TWO_HYPHENS + boundary + TWO_HYPHENS);
               dos.writeBytes(LINEND);
                 dos.flush();
                 dos.close();
                 // 返回类型
                 String responseType = conn.getHeaderField("Content-Type");
                 // 正常返回而且必须为json类型
                 if (conn.getResponseCode() == HttpURLConnection.HTTP_OK
                                 && responseType != null
                                 && responseType.indexOf(HTTP_JSON_TYPE) >= 0) {
                         responseType = (convertStreamToString(conn.getInputStream()));
                } else {
                         responseType = "{}";
                 }
                 try{conn.disconnect();}catch(Exception e){}
                 return new JSONObject(responseType);
         }