java – 无法在android中使用httpconnection连接

问题是当我在我的模拟器上运行应用程序时,它给出了连接异常的错误.然后我通过在try block中的每行之后放置toast来解决问题是在httpconnection.connect();线.

我在android清单中添加了权限,而我的logcat发出了javaio异常的警告：连接错误.

try {
        HttpURLConnection httpURLConnection = (HttpURLConnection) connection;
        //Toast.makeText(this,"urlconnection passed",Toast.LENGTH_SHORT).show();
        httpURLConnection.setAllowUserInteraction(false);
        httpURLConnection.setInstanceFollowRedirects(true);
        //Toast.makeText(this,"setting response method",Toast.LENGTH_SHORT).show();
        httpURLConnection.setRequestMethod("GET");
        //Toast.makeText(this,"connecting",Toast.LENGTH_SHORT).show();
        httpURLConnection.connect();
        Toast.makeText(this,"on response code",Toast.LENGTH_SHORT).show();
        response = httpURLConnection.getResponseCode();
        //Toast.makeText(this,"response code passed",Toast.LENGTH_SHORT).show();
        if (response == HttpURLConnection.HTTP_OK) {
            //Toast.makeText(this,"OK",Toast.LENGTH_SHORT).show();
            inputStream = httpURLConnection.getInputStream();
        }

    } catch (Exception e) {
        // TODO: handle exception
        throw new IOException("Error connecting");
    }

这里创建对象的代码：

URL url = new URL(UrlString);
URLConnection connection = url.openConnection();
if (!(connection instanceof HttpURLConnection)) 
  throw new IOException("Not a HTTP connection");