java访问外部接口 简单实现

/*使用时注意字符集 "GBK""UTF-8"*/
public static String visitPost(String urlStr, String code) {
        try{
            URL url = new URL(urlStr);
            HttpURLConnection con = (HttpURLConnection)url.openConnection();
            con.setRequestMethod("GET");
            con.connect();
            BufferedReader reader = new BufferedReader(
                                        new InputStreamReader(
                                                con.getInputStream(),code));));
            String line;
            StringBuffer buffer = new StringBuffer();
            while((line = reader.readLine()) != null) {
                buffer.append(line);
            }
            reader.close();
            con.disconnect();
            String res = buffer.toString();
            return res;
        } catch(Exception e) {
            e.printStackTrace();
        }
        return null;
    }