如何通过 HTTP POST 将 JSON 文件发送到在 JAVA 中的端口（例如 9090）上运行的服务器？

Question

I am trying to build an JAVA app (running at port 9090) which receives a JSON file from HTTP POST and converts it to an XML and sends it over to another application (APP2) which runs at a different port and further processing is done for that.

I have implemented all code accept the one to receive a JSON from HTTP POST as I am not sure how to start implementing it.

Any resource/link would be very helpful.

PS Don't ask me why this is being done in this in complex way, this is what my company expects.

The following code is implemented for APP2.

SERVER SIDE:

public class ServerSide{

static String JsonPath = "src/TestApp.json";
static String XMLPath = "TestApp";
static String Port = "Port1";
public static void main(String[] args) throws IOException, SAXException {

    //      if (args.length != 1) {
    //          System.err.println(
    //              "No argument specified");
    //          System.exit(1);
    //      }

    ConfigReader reader = new ConfigReader();
    int port = Integer.parseInt(reader.getPropValues("Port1"));
    System.out.println(port);
    //JSON to XML conversion
    try {
        JsonToXML.JsonConversion(JsonPath,XMLPath);
    } catch (ParserConfigurationException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

    ServerSocket ssock = new ServerSocket(port);
    Socket socket = ssock.accept();

    System.out.println("Server Started");

    //The InetAddress specification
    InetAddress IA = InetAddress.getByName("localhost"); 

    //Specify the file
    System.out.println("This  is the connection ");
    File file = new File("Sahil.xml");
    FileInputStream fis = new FileInputStream(file);
    BufferedInputStream bis = new BufferedInputStream(fis); 

    //Get socket's output stream
    OutputStream os = socket.getOutputStream();

    //Read File Contents into contents array 
    byte[] contents;
    long fileLength = file.length(); 
    System.out.println(" This is file length "+ fileLength);
    long current = 0;

    long start = System.nanoTime();
    while(current!=fileLength){ 
        int size = 10000;
        if(fileLength - current >= size){

            System.out.println(" This is the file length "+fileLength+" current : "+current+"size : "+size);
            current += size;  
        }
        else{ 
            size = (int)(fileLength - current); 
            current = fileLength;
            System.out.println(" This is the current "+current);
        } 
        contents = new byte[size]; 
        bis.read(contents, 0, size); 
        os.write(contents);
        System.out.println("Sending file ... "+(current*100)/fileLength+"% complete!");
    }   

    os.flush(); 
    //File transfer done. Close the socket connection!
    socket.close();
    ssock.close();
    System.out.println("File sent succesfully!");
}

}

CLIENT SIDE:

public class ClientSide{

public static void main(String[] args) throws Exception{
    String line;
        //Initialize socket
        InetAddress host = InetAddress.getLocalHost();
        Socket socket = new Socket(host.getHostName(), 4355);
        byte[] contents = new byte[10000];

        InputStream is = socket.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(is));

        //No of bytes read in one read() call
        while ((line = br.readLine()) != null){
            System.out.println(line);
        }

      socket.close(); 

        System.out.println("File saved successfully!");
    }
}

The thing I am asking about how to implement HTTP POST to send a file to APP1 which runs at a different port and in turn sends it to APP2.

Answer 1

I am not sure on how to receive a file from HTTP POST

I suppose you have some html form with file input type and correct enctype

... enctype="multipart/form-data"> <input type="file" id="input">

later in POST method handler you have to extract that file from request

Part filePart = request.getPart("file");

The only thing that I would recommend don't do the file extraction manually. Obviously use some ready to use libraries