Klasse aufrufen aus Servlet

Hallo Zusammen, ich hoffe sehr das mir hier jemand weiterhelfen kann, da ich schon schier am verzweifeln bin :frowning:

Ich muss aus einem Servlet einer Klasse aufrufen um anschlie├čend den return einer dieser Methoden wieder verarbeiten zu k├Ânnen. Da ich mit Servlets noch wenig zu tun hatte verzweifel ich hier gerade.

Mein Servlet sieht wie folgt aus:

public class ReceiveMessageServlet extends HttpServlet {

@SuppressWarnings({ "unchecked", "static-access" })
@Override
public final void doPost(final HttpServletRequest req, final HttpServletResponse resp) throws IOException {
    // Validating unique subscription token before processing the message
    String subscriptionToken = System.getProperty(Constants.BASE_PACKAGE + ".subscriptionUniqueToken");
    if (!subscriptionToken.equals(req.getParameter("token"))) {
        resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
        resp.getWriter().close();
        return;

    }

    ServletInputStream inputStream = req.getInputStream();

    // Parse the JSON message to the POJO model class
    JsonParser parser = JacksonFactory.getDefaultInstance().createJsonParser(inputStream);
    parser.skipToKey("message");
    PubsubMessage message = parser.parseAndClose(PubsubMessage.class);

    // Store the message in the datastore
    Entity messageToStore = new Entity("PubsubMessage");
    messageToStore.setProperty("message", new String(message.decodeData(), "UTF-8"));
    messageToStore.setProperty("receipt-time", System.currentTimeMillis());
    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
    datastore.put(messageToStore);

    // Invalidate the cache
    MemcacheService memcacheService = MemcacheServiceFactory.getMemcacheService();
    memcacheService.delete(Constants.MESSAGE_CACHE_KEY);

    // Acknowledge the message by returning a success code
    resp.setStatus(HttpServletResponse.SC_OK);



    resp.getWriter().close();
}

}

Und die Klasse so:

Public class Program {
   // public static JSONObject inpParms;
    public static String apikey;
    public static String apiurl;
    public static String jsonBody;

    /**
     * Read the JSON schema from the file rrsJson.json
     * 
     * @param filename It expects a fully qualified file name that contains input JSON file
     */     
    public static void readJson(String filename) {
        try {
            File apiFile = new File(filename);
            @SuppressWarnings("resource")
            Scanner sc = new Scanner(apiFile);
            jsonBody = "";
            while (sc.hasNext()) {
                jsonBody += sc.nextLine()+"\n";
            }
        }
        catch (Exception e){
            System.out.println(e.toString());
       }
    }

    /**
     * Read the API key and API URL of Azure ML request response REST API
     * 
     * @param filename fully qualified file name that contains API key and API URL
     */ 
     public static void readApiInfo(String filename) {

        try {
            File apiFile = new File(filename);
            @SuppressWarnings("resource")
            Scanner sc = new Scanner(apiFile);

            apiurl = sc.nextLine();
            apikey = sc.nextLine();

        }
        catch (Exception e){
            System.out.println(e.toString());
       }

    }

    /**
     * Call REST API for retrieving prediction from Azure ML 
     * @return response from the REST API
     */ 
    @SuppressWarnings("deprecation")
    public static String rrsHttpPost() {

        HttpPost post;
        HttpClient client;
        StringEntity entity;

        try {
            // create HttpPost and HttpClient object
            post = new HttpPost(apiurl);
            client = HttpClientBuilder.create().build();

           // setup output message by copying JSON body into 
           // apache StringEntity object along with content type
           entity = new StringEntity(jsonBody, HTTP.UTF_8);
           entity.setContentEncoding(HTTP.UTF_8);
           entity.setContentType("text/json");


           // add HTTP headers
           post.setHeader("Accept", "text/json");
           post.setHeader("Accept-Charset", "UTF-8");

           // set Authorization header based on the API key
           post.setHeader("Authorization", ("Bearer "+apikey));
           post.setEntity(entity);

           // Call REST API and retrieve response content
           HttpResponse authResponse = client.execute(post);

           return EntityUtils.toString(authResponse.getEntity());

        }
        catch (Exception e) {

            return e.toString();
       }

   }

    /**
     * @param args the command line arguments specifying JSON and API info file names
     */
    public static void main(String[] args) {
        // check for mandatory argments. This program expects 2 arguments 
        // first argument is full path with file name of JSON file and 
        // second argument is full path with file name of API file that contains API URL and API Key of request response REST API
        if (args.length < 2) {
            System.out.println("Incorrect usage. Please use the following calling pattern");
            System.out.println("java AzureML_RRSApp <jsonFilename> <apiInfoFilename>");
        }

        try {

            // read JSON file name
           String jsonFile = "rrsJson.json";
            // read API file name
            String apiFile = "apiInfo.txt";

            // call method to read API URL and key from API file
            readApiInfo(apiFile);

            // call method to read JSON input from the JSON file
          readJson(jsonFile);

            // print the response from REST API
         System.out.println(rrsHttpPost());
         }
        catch (Exception e) {
            System.out.println(e.toString());
        }
   }
}

Es geht um die Methode: public static String rrsHttpPost()

Wie kann ich den R├╝ckgabewert in mein Servlet ├╝bernehmen und wie rufe ich diese Klasse auf damit sie l├Ąuft?

Ich bedanke mich f├╝r eure Hilfe.

OhÔÇŽ Ich will dir in keinsterweise zu Nahe treten, aber hast du dich auch mal mit Java befasst, bevor du dich mit Servlets befasst hast? NajaÔÇŽ wenn man Java f├╝r die Programmierung von Servlets lernt, ist das Ok. Aber an Grundlagen kommt man dennoch nicht vorbei.

Statische Methoden ruft man auf dem jeweiligen Klassennamen auf. F├╝r deinen Fall gilt also:

String rssHttpPost = Program.rrsHttpPost();

Das ist eine essentielle Java-Grundlage, die man auch dort beherzigen sollte, wo

@SuppressWarnings({ "unchecked", "static-access" })

im Code steht. :wink: