Quickstart: Translate text with Java

In this quickstart, you translate text from one language to another using the Translator Text API.

Prerequisites

You'll need JDK 7 or 8 to compile and run this code. You can use a Java IDE if you have a favorite, but a text editor will also work.

To use the Translator Text API, you also need a subscription key; see How to sign up for the Translator Text API.

Translate request

The following code translates source text from one language to another using the Translate method.

  1. Create a new Java project in your favorite code editor.
  2. Add the code provided below.
  3. Replace the subscriptionKey value with an access key valid for your subscription.
  4. Run the program.
import java.io.*;
import java.net.*;
import java.util.*;
import javax.net.ssl.HttpsURLConnection;

/*
 * Gson: https://github.com/google/gson
 * Maven info:
 *     groupId: com.google.code.gson
 *     artifactId: gson
 *     version: 2.8.1
 */
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

/* NOTE: To compile and run this code:
1. Save this file as Translate.java.
2. Run:
    javac Translate.java -cp .;gson-2.8.1.jar -encoding UTF-8
3. Run:
    java -cp .;gson-2.8.1.jar Translate
*/

public class Translate {

// **********************************************
// *** Update or verify the following values. ***
// **********************************************

// Replace the subscriptionKey string value with your valid subscription key.
    static String subscriptionKey = "ENTER KEY HERE";

    static String host = "https://api.cognitive.microsofttranslator.com";
    static String path = "/translate?api-version=3.0";

    // Translate to German and Italian.
    static String params = "&to=de&to=it";

    static String text = "Hello world!";

    public static class RequestBody {
        String Text;

        public RequestBody(String text) {
            this.Text = text;
        }
    }

    public static String Post (URL url, String content) throws Exception {
        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setRequestProperty("Content-Length", content.length() + "");
        connection.setRequestProperty("Ocp-Apim-Subscription-Key", subscriptionKey);
        connection.setRequestProperty("X-ClientTraceId", java.util.UUID.randomUUID().toString());
        connection.setDoOutput(true);

        DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
        byte[] encoded_content = content.getBytes("UTF-8");
        wr.write(encoded_content, 0, encoded_content.length);
        wr.flush();
        wr.close();

        StringBuilder response = new StringBuilder ();
        BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
        String line;
        while ((line = in.readLine()) != null) {
            response.append(line);
        }
        in.close();

        return response.toString();
    }

    public static String Translate () throws Exception {
        URL url = new URL (host + path + params);

        List<RequestBody> objList = new ArrayList<RequestBody>();
        objList.add(new RequestBody(text));
        String content = new Gson().toJson(objList);

        return Post(url, content);
    }

    public static String prettify(String json_text) {
        JsonParser parser = new JsonParser();
        JsonElement json = parser.parse(json_text);
        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        return gson.toJson(json);
    }

    public static void main(String[] args) {
        try {
            String response = Translate ();
            System.out.println (prettify (response));
        }
        catch (Exception e) {
            System.out.println (e);
        }
    }
}

Translate response

A successful response is returned in JSON as shown in the following example:

[
  {
    "detectedLanguage": {
      "language": "en",
      "score": 1.0
    },
    "translations": [
      {
        "text": "Hallo Welt!",
        "to": "de"
      },
      {
        "text": "Salve, mondo!",
        "to": "it"
      }
    ]
  }
]

Next steps

Explore the sample code for this quickstart and others, including transliteration and language identification, as well as other sample Translator Text projects on GitHub.