java - 如何在服务器上接收来自同一客户端的多个 POST 请求

Question

我正在尝试编写一个 java 服务器和客户端，以便客户端向服务器发送一个 POST 请求，其中包含从文件中读取的一些 xml 字符串作为有效负载，服务器从客户端获取请求并向其发送确认，并且此过程重复直到客户端已发送的所有 xml 字符串（作为单独的 POST 请求）。

我已经为客户端和服务器之间的 1 次请求和响应的单次交换编写了代码。但是我无法为来自同一个客户端的多个请求扩展它，因为客户端等待服务器的响应并且服务器的响应不会发送到客户端，直到我在 DataOutputStream 对象中写入wr.close()或写入字节之后。socket.close()但是，一旦我编写了这两个命令中的任何一个，服务器和客户端之间的连接就会关闭，客户端需要重新建立连接才能发送第二个请求。

这是我的服务器端函数，它接收请求并发送响应：

public HTTPServer(int port) {
        try {
            private ServerSocket server = new ServerSocket(port);
            private Socket socket = server.accept();
            int ind = 0;

            while (ind<19) {

                //socket is an instance of Socket
                InputStream is = socket.getInputStream();
                InputStreamReader isReader = new InputStreamReader(is);
                BufferedReader br = new BufferedReader(isReader);

                //code to read and print headers
                String headerLine = null;
                while ((headerLine = br.readLine()).length() != 0) {
                    System.out.println(headerLine);
                }

                ind++;

                //send response to the client
                Date today = new Date();
                String httpResponse = "HTTP/1.1 200 OK\r\n\r\n" + today;
                DataOutputStream wr = new DataOutputStream(socket.getOutputStream());
                wr.writeBytes(httpResponse);
                wr.flush();
            }
            socket.close();         // or wr.close()

        } catch (IOException i) {
            System.out.println(i);
        }
    }

这是我的客户端代码：

public void postMessage() throws IOException {
        // string to read message from input
        File folder = new File("path/to/my/files");
        String[] listOfFiles = folder.list();

        for (int i = 0; i < listOfFiles.length; i++) {
            File file = new File(listOfFiles[i]);
            Scanner sc = null;
            try {
                sc = new Scanner(file);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

            final URL url = new URL("http://localhost:8080");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "text/xml; charset=UTF-8");
            conn.setDoOutput(true);
            conn.setConnectTimeout(5000);

            // Send post request
            conn.setDoOutput(true);
            DataOutputStream wr = new DataOutputStream(conn.getOutputStream());

            String line = "";
            while (sc.hasNextLine()) {
                line += sc.nextLine();
                line += '\n';
            }
            wr.writeBytes(line);
            wr.flush();
            wr.close();


            // read response
            BufferedReader in;
            if (200 <= conn.getResponseCode() && conn.getResponseCode() <= 299) {
                in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(conn.getErrorStream()));
            }
            String str;
            while ((str = in.readLine()) != null) {
                System.out.println(str);
            }
        }
    }

除非我写socket.close()或wr.close()之后wr.flush()，否则我的响应不会发送到客户端并且客户端会一直等待它，但是一旦我这样做，服务器套接字就会关闭并且代码终止。如何在不必关闭套接字的情况下向我的客户端发送响应？

编辑：这是更新的 HTTP 客户端代码，它使用套接字发送 HTTP 请求，但错误仍然存​​在。

public static void main(String[] args) throws Exception {
        InetAddress addr = InetAddress.getByName("localhost");
        Socket socket = new Socket(addr, 8080);
        boolean autoflush = true;

        // string to read message from input
        File folder = new File("/Users/prachisingh/IdeaProjects/requests_responses");
        String[] listOfFiles = folder.list();

        for (int i = 0; i < listOfFiles.length; i++) {
            System.out.println("File " + listOfFiles[i]);
            File file = new File("/Users/prachisingh/IdeaProjects/requests_responses/" + listOfFiles[i]);

            Scanner sc = null;
            try {
                sc = new Scanner(file);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

            String line = "";
            while (sc.hasNextLine()) {
                line += sc.nextLine();
                line += '\n';
            }

            PrintWriter out = new PrintWriter(socket.getOutputStream(), autoflush);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            // send an HTTP request to the web server
            out.println("POST / HTTP/1.1");
            out.println("Host: http://localhost:8080");
            out.println(line);
            out.println();

            // read the response
            boolean loop = true;
            StringBuilder sb = new StringBuilder(8096);
            while (loop) {
                if (in.ready()) {
                    int r = 0;
                    while (r != -1) {
                        r = in.read();
                        sb.append((char) r);
                    }
                    loop = false;
                }
            }
            System.out.println(sb.toString());
        }
        socket.close();
    }

标签： javasocketsxmlhttprequest