(android功能代码) android文件上传服务器

/** * 通过拼接的方式构造请求内容，实现参数传输以及文件传输 * @param actionUrl * @param params * @param files * @return * @throws IOException */ public static String post(String actionUrl, Map<String, String> params,      Map<String, File> files) throws IOException {    String BOUNDARY = java.util.UUID.randomUUID().toString();   String PREFIX = "--" , LINEND = "\r\n";   String MULTIPART_FROM_DATA = "multipart/form-data";    String CHARSET = "UTF-8";   URL uri = new URL(actionUrl);    HttpURLConnection conn = (HttpURLConnection) uri.openConnection();    conn.setReadTimeout(5 * 1000); // 缓存的最长时间    conn.setDoInput(true);// 允许输入    conn.setDoOutput(true);// 允许输出    conn.setUseCaches(false); // 不允许使用缓存    conn.setRequestMethod("POST");    conn.setRequestProperty("connection", "keep-alive");    conn.setRequestProperty("Charsert", "UTF-8");    conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA + ";boundary=" + BOUNDARY);    // 首先组拼文本类型的参数    StringBuilder sb = new StringBuilder();    for (Map.Entry<String, String> entry : params.entrySet()) {      sb.append(PREFIX);      sb.append(BOUNDARY);      sb.append(LINEND);      sb.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"" + LINEND);     sb.append("Content-Type: text/plain; charset=" + CHARSET+LINEND);     sb.append("Content-Transfer-Encoding: 8bit" + LINEND);     sb.append(LINEND);     sb.append(entry.getValue());      sb.append(LINEND);    }    DataOutputStream outStream = new DataOutputStream(conn.getOutputStream());    outStream.write(sb.toString().getBytes());    // 发送文件数据    if(files!=null){     int i = 0;     for (Map.Entry<String, File> file: files.entrySet()) {        StringBuilder sb1 = new StringBuilder();        sb1.append(PREFIX);        sb1.append(BOUNDARY);        sb1.append(LINEND);        sb1.append("Content-Disposition: form-data; name=\"file"+(i++)+"\"; filename=\""+file.getKey()+"\""+LINEND);       sb1.append("Content-Type: application/octet-stream; charset="+CHARSET+LINEND);       sb1.append(LINEND);       outStream.write(sb1.toString().getBytes());        InputStream is = new FileInputStream(file.getValue());       byte[] buffer = new byte[1024];        int len = 0;        while ((len = is.read(buffer)) != -1) {          outStream.write(buffer, 0, len);        }       is.close();        outStream.write(LINEND.getBytes());      }    }      //请求结束标志   byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();    outStream.write(end_data);    outStream.flush();    //得到响应码    int res = conn.getResponseCode();    InputStream in = null;   if (res == 200) {     in = conn.getInputStream();      int ch;      StringBuilder sb2 = new StringBuilder();      while ((ch = in.read()) != -1) {        sb2.append((char) ch);      }    }   return in == null ? null : in.toString();  }