从网络上载文本出错

从网络下载文本出错

Java code

public String GetText(String urlStr)    {        StringBuffer sb = new StringBuffer();          String line = null;          BufferedReader buffer = null;          try {              URL url = new URL(urlStr);              HttpURLConnection urlConn = (HttpURLConnection) url                      .openConnection();              buffer = new BufferedReader(new InputStreamReader(urlConn                      .getInputStream()));              while ((line = buffer.readLine()) != null) {                  sb.append(line);              }            } catch (Exception e) {              e.printStackTrace();          }        return sb.toString();      }

权限什么的也加了，一直返回null。
buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));  
似乎是这句出的错，求助

[解决办法]
buffer = new BufferedReader(new InputStreamReader(urlConn
.getInputStream()));

这个之前进行urlConn.connect();
[解决办法]
// 创建一个URL
 url = new URL(urlStr);
 // 根据url创建一个Http连接
 HttpURLConnection connection = (HttpURLConnection) url
 .openConnection();
 // 根据创建的connection来用io流操作. 先得到文件字节流, 转换成字符流, 再转换成带缓冲的. 这样方便读取
 buffer = new BufferedReader(new InputStreamReader(
 connection.getInputStream()));
 // 一行一行的读出数据
 while ((line = buffer.readLine()) != null)
 {
 strbuf.append(line);
 }