从Java中的HTTP POST请求中读取JSON消息 [英] Read JSON message from HTTP POST request in Java

问题描述

我是Java和客户端服务器编程的新手。

I am new to Java and to client- server programming.

我正在使用嵌入式Jetty，而我正在尝试将JSON字符串发送到某个地址（ http：// localhost：7070 / json ）然后在该地址中显示JSON字符串。

I am using embedded Jetty, and I'm trying to send a JSON string to some address (http://localhost:7070/json) and then to display the JSON string in that address.

我尝试了以下代码，但我得到的只是null。

I tried the following code but all I get is null.

嵌入式Jetty代码：

Embedded Jetty code:

public static void main(String[] args) throws Exception {
    Server server = new Server(7070);
    ServletContextHandler handler = new ServletContextHandler(server, "/json");
    handler.addServlet(ExampleServlet.class, "/");
    server.start();
}

发送Http POST的客户端功能：

Client side function for sending the Http POST:

public static void sendHttp(){
    HttpClient httpClient = HttpClientBuilder.create().build(); //Use this instead 

    try {
        HttpPost request = new HttpPost("http://localhost:7070/json");

        JSONObject object = new JSONObject();
        try {
            object.put("name", "MyName");
            object.put("age", "26");
        } catch (Exception ex) {
            System.out.println("Error: " + ex.getMessage());
        }

        String message = object.toString();
        request.setEntity(new StringEntity(message, "UTF8"));
        request.setHeader("Content-type", "application/json");

        HttpResponse response = httpClient.execute(request);

        // handle response here...
    }catch (Exception ex) {
        // handle exception here
    } finally {
    }
}

和Servlet函数：

And Servlet functions:

public class ExampleServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //System.out.println("test get\n");
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //System.out.println("test post\n");
        PrintWriter out = resp.getWriter();
        String json_str = req.getParameter("name");
        out.print(json_str);
    }
}

我从测试类中调用sendHttp（）方法，运行嵌入式Jetty服务器代码后（如果这很重要）。

I call the sendHttp() method from a test class, after running the embedded Jetty server code (if that matters).

推荐答案

这是我的代码，这个工作正常

Here is my code this works fine

    String data = "";   
    StringBuilder builder = new StringBuilder();
    BufferedReader reader = request.getReader();
    String line;
    while ((line = reader.readLine()) != null) {
        builder.append(line);
    }
    data = builder.toString();
    JSONObject object = new JSONObject(data); 
   //or JSONArray array = new JSONArray(data); which ever the one you want

祝你好运.....

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