如何从我的java类发送字符串到servlet

Question

Client.java 将字符串发送到servlet

    String url = "http://localhost:8084/Lab/url";

    URL obj = new URL(url);
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();

    // optional default is GET
    con.setRequestMethod("GET");
            con.setDoInput(true);
            con.setDoOutput(true);
            dos = new DataOutputStream(con.getOutputStream());
            dos.writeBytes(resultJson.toString());
    int responseCode = con.getResponseCode();
            BufferedReader in = new BufferedReader(new InputStreamReader(
                                con.getInputStream()));
            String inputLine;
            while ((inputLine = in.readLine()) != null) 
                System.out.println(inputLine);

            dos.flush();
            dos.close();
            in.close();

的Servlet 从客户端获取值并返回

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();

我不知道接下来该做什么。

Answer 1

尝试以下方法：

1. 要将字符串作为参数传递，请将 String url = "[http://localhost:8084/Lab/url]"; 替换为 String url = "[http://localhost:8084/Lab/url?str=YOURSTRING]";
2. 在servlet中，要检索消息add： String messsage = request.getParameter（“str”）;


在[1]中使用 GET ，我们在包含字符串的URL中传递“str”参数。 我们使用servlet [2]中的getParameter()检索消息。

正如@Anders所说，我们也可以使用 POST

来做到这一点

我希望这有用。

干杯

PS：URLS没有[]


的 [UPDATE]
使用POST发送参数

    String param = "str=YOURSTRING";
    String request = "http://localhost:8084/";
    URL url = new URL(request);
    HttpURLConnection connection = (HttpURLConnection)
    url.openConnection();          
    connection.setDoOutput(true);
    connection.setDoInput(true);
    connection.setInstanceFollowRedirects(false);
    connection.setRequestMethod("POST");
    connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
    connection.setRequestProperty("charset", "utf-8");
    connection.setRequestProperty("Content-Length", "" +  Integer.toString(param.getBytes().length));
    connection.setUseCaches (false);

    DataOutputStream out = new DataOutputStream(connection.getOutputStream ());
    out.writeBytes(param);
    out.flush();
    out.close();
    connection.disconnect();