---
title: How to Create a Facebook Messenger Bot With Java
date: 2017-10-20 00:00:00
featured_image: https://images.unsplash.com/photo-1526590776442-5541f7dcf2c8?q=90&fm=jpg&w=1000&fit=max
excerpt: Today I’ll show you how to build your own Facebook Messenger Chat Bot in Java. We’ll use Spark Web Framework, Racter Java Package, Gradle and Ngrok. So Let’s get started.
---

![](https://images.unsplash.com/photo-1526590776442-5541f7dcf2c8?q=90&fm=jpg&w=1000&fit=max)

Today I’ll show you how to build your own Facebook Messenger Chat Bot in Java. We’ll use <a href="http://sparkjava.com/" rel="noopener" target="_blank">Spark Web Framework</a>, <a href="https://github.com/clivern/racter" rel="noopener" target="_blank">Racter Java Package</a>, <a href="https://gradle.org/" rel="noopener" target="_blank">Gradle</a> and <a href="https://ngrok.com/" rel="noopener" target="_blank">Ngrok.</a> So Let’s get started.

##### Create Our Chat Bot with Java

We need install spark framework and set all required third party packages like racter.

```bash
$ mkdir dunk
$ gradle wrapper --gradle-version=4.0
$ nano build.gradle
```

and Insert the following into our `build.gradle` file.

```java
/*
 * This build file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java Library project to get you started.
 * For more details take a look at the Java Libraries chapter in the Gradle
 * user guide available at https://docs.gradle.org/4.0/userguide/java_library_plugin.html
 */

// Apply the java-library plugin to add support for Java Library
apply plugin: 'java-library'
apply plugin: 'application'

archivesBaseName = "dunk"
version = '1.0.0'
mainClassName = "com.clivern.dunk.Main"

// In this section you declare where to find the dependencies of your project
repositories {
    // Use jcenter for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
    mavenCentral()
    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}

dependencies {
    compile 'com.sparkjava:spark-core:2.6.0'
    compile 'org.slf4j:slf4j-api:1.7.13'
    compile 'org.slf4j:slf4j-simple:1.7.13'
    compile 'com.clivern:racter:1.0.2'
}

//create a single Jar with all dependencies
task fatJar(type: Jar) {
	manifest {
        attributes 'Implementation-Title': 'Dunk ChatBot',
        	'Implementation-Version': version,
        	'Main-Class': mainClassName
    }
    baseName = archivesBaseName + '_fat'
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    with jar
}
```

Then we need to build our folder structure

```bash
$ mkdir -p src/main/java/com/clivern/dunk
$ mkdir -p src/main/java/resources
```

Then let's create our main controller that has 2 end points. The first one is to verify token and the other one to process the inbound messages and events.

```java
/*
 * Copyright (C) 2017 Clivern. <https://clivern.com>
 */
package com.clivern.dunk;

import static spark.Spark.*;
import com.clivern.racter.BotPlatform;
import com.clivern.racter.receivers.webhook.*;

import com.clivern.racter.senders.*;
import com.clivern.racter.senders.templates.*;

import java.util.HashMap;
import java.util.Map;
import java.io.IOException;

public class Main {

    public static void main(String[] args) throws IOException
    {
        // Verify Token Route
        get("/", (request, response) -> {
            BotPlatform platform = new BotPlatform("src/main/java/resources/config.properties");
            platform.getVerifyWebhook().setHubMode(( request.queryParams("hub.mode") != null ) ? request.queryParams("hub.mode") : "");
            platform.getVerifyWebhook().setHubVerifyToken(( request.queryParams("hub.verify_token") != null ) ? request.queryParams("hub.verify_token") : "");
            platform.getVerifyWebhook().setHubChallenge(( request.queryParams("hub.challenge") != null ) ? request.queryParams("hub.challenge") : "");

            if( platform.getVerifyWebhook().challenge() ){
                platform.finish();
                response.status(200);
                return ( request.queryParams("hub.challenge") != null ) ? request.queryParams("hub.challenge") : "";
            }

            platform.finish();
            response.status(403);
            return "Verification token mismatch";
        });

        post("/", (request, response) -> {
            String body = request.body();
            BotPlatform platform = new BotPlatform("src/main/java/resources/config.properties");
            platform.getBaseReceiver().set(body).parse();
            HashMap<String, MessageReceivedWebhook> messages = (HashMap<String, MessageReceivedWebhook>) platform.getBaseReceiver().getMessages();
            for (MessageReceivedWebhook message : messages.values()) {

                String user_id = (message.hasUserId()) ? message.getUserId() : "";
                String page_id = (message.hasPageId()) ? message.getPageId() : "";
                String message_id = (message.hasMessageId()) ? message.getMessageId() : "";
                String message_text = (message.hasMessageText()) ? message.getMessageText() : "";
                String quick_reply_payload = (message.hasQuickReplyPayload()) ? message.getQuickReplyPayload() : "";
                Long timestamp = (message.hasTimestamp()) ? message.getTimestamp() : 0;
                HashMap<String, String> attachments = (message.hasAttachment()) ? (HashMap<String, String>) message.getAttachment() : new HashMap<String, String>();

                platform.getLogger().info("User ID#:" + user_id);
                platform.getLogger().info("Page ID#:" + page_id);
                platform.getLogger().info("Message ID#:" + message_id);
                platform.getLogger().info("Message Text#:" + message_text);
                platform.getLogger().info("Quick Reply Payload#:" + quick_reply_payload);

                for (String attachment : attachments.values()) {
                    platform.getLogger().info("Attachment#:" + attachment);
                }

                String text = message.getMessageText();
                MessageTemplate message_tpl = platform.getBaseSender().getMessageTemplate();
                ButtonTemplate button_message_tpl = platform.getBaseSender().getButtonTemplate();
                ListTemplate list_message_tpl = platform.getBaseSender().getListTemplate();
                GenericTemplate generic_message_tpl = platform.getBaseSender().getGenericTemplate();
                ReceiptTemplate receipt_message_tpl = platform.getBaseSender().getReceiptTemplate();

                if( text.equals("text") ){

                    message_tpl.setRecipientId(message.getUserId());
                    message_tpl.setMessageText("Hello World");
                    message_tpl.setNotificationType("REGULAR");
                    platform.getBaseSender().send(message_tpl);

                }else if( text.equals("image") ){

                    message_tpl.setRecipientId(message.getUserId());
                    message_tpl.setAttachment("image", "http://techslides.com/demos/samples/sample.jpg", false);
                    message_tpl.setNotificationType("SILENT_PUSH");
                    platform.getBaseSender().send(message_tpl);

                }else if( text.equals("file") ){

                    message_tpl.setRecipientId(message.getUserId());
                    message_tpl.setAttachment("file", "http://techslides.com/demos/samples/sample.pdf", false);
                    message_tpl.setNotificationType("NO_PUSH");
                    platform.getBaseSender().send(message_tpl);

                }else if( text.equals("video") ){

                    message_tpl.setRecipientId(message.getUserId());
                    message_tpl.setAttachment("video", "http://techslides.com/demos/samples/sample.mp4", false);
                    platform.getBaseSender().send(message_tpl);

                }else if( text.equals("audio") ){

                    message_tpl.setRecipientId(message.getUserId());
                    message_tpl.setAttachment("audio", "http://techslides.com/demos/samples/sample.mp3", false);
                    platform.getBaseSender().send(message_tpl);

                }
                return "ok";
            }
            return "bla";
        });
    }
}
```

Then we need to create our `config.properties` file that contains our facebook app settings and some additional settings for racter package.

```bash
$ nano src/main/java/resources/config.properties
```

It should look like the following. In the next steps, we will know how to get `app_id`, `verify_token` and `page_access_token`

```
app_id=app id here
verify_token=verify token here
page_access_token=access token here
log_console_status=false
log_console_level=ALL
log_file_status=false
log_file_level=ALL
log_file_path=src/main/java/resources/app.log
log_file_limit=1
log_file_count=200000
log_file_append=true
```

Now Our App is good to go. Open two terminals one to run our app and another to create a secure web tunnel to localhost & port 4567 with ngrok

```bash
$ ./gradlew run
```

```bash
$ ngrok http 4567
```

![](/images/blog/bot_5.png)
![](/images/blog/bot_6.png)

##### Create a Facebook Page

We need to create a Facebook Page if you don’t already have one because In order to communicate with your chat bot, people will need to go through your page.

##### Create a Facebook App

Go to the [Facebook Developer Page](https://developers.facebook.com/quickstarts/?platform=web) and click “Skip and Create App ID” at the top right. Then create a new Facebook App for your chat bot and give your app a name and contact email.

![](/images/blog/bot_1.png)

You can get the app id and insert that id in `config.properties` file you created before on java app.

![](/images/blog/bot_3.png)

From the Messenger settings for your Facebook App, You can connect your app with the facebook page to get access token.

![](/images/blog/bot_2.png)

Then we need to setup our webhook like the following:

![](/images/blog/bot_7.png)

Please note that, You can set Verify Token to be any value and pass that value to our `config.properties` file and restart our app (Just stop it and run `./gradlew run`).

Then click Verify and Save. Now Our Webhook should be look like the following

![](/images/blog/bot_9.png)

After you’ve configured your webhook, Just subscribe to the specific page you want to receive message notifications for.

##### Chat with Your Bot

Go to the Facebook Page you created and click on “Message” button. This should open a message pane with your Page.
Start sending your Page messages and the bot should reply!

![](/images/blog/bot.ogv.gif)

[To Check The Full Code!](https://github.com/clivern/dunk)
[To Check All Features that Racter Supports or Help Us Make it Much More Better!](https://github.com/clivern/racter)