如何用Servlet调用本地接口

要用Servlet调用本地接口，可以使用Java提供的URLConnection或HttpClient来实现。

以下是使用URLConnection调用本地接口的示例代码：

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    URL url = new URL("http://localhost:8080/your/local/api");
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("GET");
    conn.setRequestProperty("Accept", "application/json");

    if (conn.getResponseCode() != 200) {
        throw new RuntimeException("Failed : HTTP error code : "
                + conn.getResponseCode());
    }

    BufferedReader br = new BufferedReader(new InputStreamReader(
            (conn.getInputStream())));

    String output;
    System.out.println("Output from Server .... \n");
    while ((output = br.readLine()) != null) {
        System.out.println(output);
    }

    conn.disconnect();
}

这段代码发送一个GET请求到地址为"http://localhost:8080/your/local/api"的本地接口，并将返回的JSON数据打印到控制台上。可以根据需要修改请求方法、请求头和请求参数等。