調用第三方接口，返回String類型

public static String test(String paramter){
        try{
            URL url = new URL("http://127.0.0.1:8056/api?paramter="+paramter);
            //調用URL對象的openConnection( )來獲取HttpURLConnection對象實例
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            //請求方法爲POST
            conn.setRequestMethod("POST");
            //設置鏈接超時爲5秒
            conn.setConnectTimeout(5000);
            //容許輸入輸出
            conn.setDoInput(true);
            conn.setDoOutput(true);
            //不能緩存
            conn.setUseCaches(false);
            //設置頭部信息
            conn.setRequestProperty("headerdata", "ceshiyongde");
            //設置 Content-Type
            conn.setRequestProperty("Content-Type", "application/Json; charset=UTF-8");
            //服務器返回東西了，先對響應碼判斷
            String result = null;
            if (conn.getResponseCode() == 200) {
                //用getInputStream()方法得到服務器返回的輸入流
                InputStream in = conn.getInputStream();
                //流轉換爲二進制數組，read()是轉換方法
                byte[] data = new byte[1024];
                int len = 0;
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                while ((len = in.read(data)) != -1){
                    bos.write(data,0,len);
                }
                bos.close();
                result= new String(bos.toByteArray(), "UTF-8");
                in.close();
            }
            return result;
        }catch (Exception e){
            e.printStackTrace();
            return null;
        }

    }