随手记java发送Get和Psot请求方法（请求三方接口）

/**
     * 发送Get请求
     *
     * @param url 请求URL
     * @return {@link String}
     */
    private String sendHttpRequestGet(String url) {
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            URL requestUrl = new URL(url);
            connection = (HttpURLConnection) requestUrl.openConnection();
            connection.setRequestMethod("GET");
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setUseCaches(false);
            connection.connect();

            reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            StringBuilder stringBuilder = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                stringBuilder.append(line);
            }
            return stringBuilder.toString();
        } catch (IOException e) {
            System.err.println("Error connecting to " + url + ": " + e.getMessage());
            return null;
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

  /**
     * 发送JSON POST请求，并返回响应结果
     * @param url 请求URL
     * @param json 请求的JSON数据
     * @return 响应结果，如果请求失败，则返回null
     */
    public static String sendHttpRequsetPost(String url, String json) {
        try {
            //创建一个HttpURLConnection对象
            HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();

            //设置请求方法为POST
            con.setRequestMethod("POST");

            //启用输出，因为我们将向服务器发送数据
            con.setDoOutput(true);

            //设置请求的内容类型
            con.setRequestProperty("Content-Type", "application/json");

            //将JSON数据写入输出流
            try(OutputStream os = con.getOutputStream()) {
                byte[] input = json.getBytes("utf-8");
                os.write(input, 0, input.length);
            }

            //获取响应代码
            int responseCode = con.getResponseCode();
            if (responseCode != 200) {
                return null; //请求失败，返回null
            }

            //读取响应
            try(BufferedReader in = new BufferedReader(
                    new InputStreamReader(con.getInputStream()))) {
                String line;
                StringBuilder response = new StringBuilder();
                while ((line = in.readLine()) != null) {
                    response.append(line);
                }
                return response.toString(); //返回响应结果
            }
        } catch(Exception e) {
            System.err.println("Exception in sending POST request: " + e.getMessage());
            return null;
        }
    }