java http调用方式get post 包含带header

public  String  CreateUser(){
BufferedReader reader = null;
String result = null;
String httpUrl="http://xxx.xxx.xxx/xxx?";
StringBuffer sbf = new StringBuffer();
String  httpArg="xxx=&xxx=";
httpUrl = httpUrl + "" + httpArg;
try {
URL url = new URL(httpUrl);
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
connection.setRequestMethod("POST");  //POST，Get
// HTTP header
//connection.setRequestProperty("Host","upcaiyun2.com");

connection.connect();
InputStream is = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
String strRead = null;
while ((strRead = reader.readLine()) != null) {
sbf.append(strRead);
sbf.append("\r\n");
}
reader.close();
result = sbf.toString();
} catch (Exception e) {
e.printStackTrace();
}
return result;
}