将输入流InputStream转换为String

 public static String convertStreamToString(InputStream is) {
         /*
           * To convert the InputStream to String we use the BufferedReader.readLine()
           * method. We iterate until the BufferedReader return null which means
           * there's no more data to read. Each line will appended to a StringBuilder
           * and returned as String.
           */
          BufferedReader reader = new BufferedReader(new InputStreamReader(is));
          StringBuilder sb = new StringBuilder();      

          String line = null;
         try {
             while ((line = reader.readLine()) != null) {
                  sb.append(line + "\n");
              }
          } catch (IOException e) {
              e.printStackTrace();
          } finally {
             try {
                  is.close();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }      

         return sb.toString();
      } 

二、推荐一个jar包，用来转换InputStream到String，代码示例如下：

 // 引入apache的io包
 import org.apache.commons.io.IOUtils;

 InputStream in = con.getInputStream();
 String result = IOUtils.toString(in, "UTF-8");