## Overview

Here we are going to use Spring Boot Maven to **Build a JAVA Telegram bot** which (echoes) _sends back the received text message_ to the user. Then we are going to **deploy our bot on Heroku**.
Let's get in by assuming you have a _basic knowledge_ in Java.

---

## Prerequisites

- A Code Editor
  - [VSCode](https://vscode.dev?ref=vinuxd.github.io) or [Eclipse](https://eclipse.org/ide?ref=vinuxd.github.io)
- JDK 11 or more
- Patience and Time.

## Initializing our code

- First things first, Go to the following link which points to [Spring Initializr](https://start.spring.io/#!type=maven-project&language=java&platformVersion=2.6.4&packaging=jar&jvmVersion=11&groupId=com.echobot&artifactId=echobotexample&name=echobotexample&description=Simple%20Echo%20Bot%20in%20JAVA&packageName=com.echobot.echobotexample)'s official webpage and download the premade configuration I made to initialize our project.
- Unzip the downloaded file to your preffered location.
- Open your preferred code editor and hit _Import existing project._

## Adding dependencies

- Find a file named `pom.xml` in the root of your project. Open the file and add the following dependencies.
- If you look carefully you can see the following tags in our `pom.xml` file.

```xml
<dependencies>

  </dependencies>
```

- And that's the right place to add our dependencies.
- We are going to use Rubenlagus [TelegramBots](https://github.com/Rubenlagus/TelegramBots) library to build our bot.
- Add the following contents in the `<dependencies>` section.

```xml
<dependencies>

     <dependency>
       <groupId>org.telegram</groupId>
       <artifactId>telegrambots-spring-boot-starter</artifactId>
       <version>5.7.1</version>
    </dependency>

</dependencies>
```

- Save and Update the project by using `Shift+Alt+U` or with the `Sync` button and we are done adding dependencies.

## Declaring Env Variables

- To make our bot work we need to declare some environmental variables.
- Here we are going to add two mandatory variables named,
  - BOT_TOKEN
  - BOT_USERNAME
- Since it was a Spring Boot application, We need to add a variable named,
  - PORT
- Navigate to `src\main\resources` and rename `application.properties` to `applicaton.yml` and add the following variables.

```yml
bot:
  BOT_TOKEN: <Super_Secret_Token_Here>
  BOT_USERNAME: <ExampleBot>
server:
  PORT: 5000
```

## Programming Part

- Navigate to `src/main/java/com/echobot/echobotexample`.
- You can see there will be a file named `EchobotexampleApplication.java` and thats the **main class** of our project. _Leave the file as it is_.
- Create a class file named `EchoBot.java `in the same directory and that's the actual **bot class**.

### Things to do

- Importing Packages
- Getting Variables
- getBotToken() method
- getbotUsername() method
- onUpdateReceived() method
- Procfile

### Importing Packages

- Lets import the necessary packages and make our `EchoBot` class extending `TelegramLongPollingBot`. (We aren't using Webhook here)

```java
// Defining Package name
package com.echobot.echobotexample;

// @Value annotation
import org.springframework.beans.factory.annotation.Value;
// @Component annotation
import org.springframework.stereotype.Component;
// LongPollingBot class
import org.telegram.telegrambots.bots.TelegramLongPollingBot;
// Update Method
import org.telegram.telegrambots.meta.api.objects.Update;
// SendMessage method
import org.telegram.telegrambots.meta.api.methods.send.SendMessage;

@Component
class EchoBot extends TelegramLongPollingBot {

}
```

### Getting Variables

- We are going to get the `BOT_TOKEN` and `BOT_USERNAME` from `application.yml` to our java file.

```java
String BOT_TOKEN;
String BOT_USERNAME;

EchoBot(@Value("${bot.BOT_TOKEN}") String BOT_TOKEN, @Value("${bot.BOT_USERNAME}") String BOT_USERNAME) {
        this.BOT_TOKEN = BOT_TOKEN;
        this.BOT_USERNAME = BOT_USERNAME;
    }
```

### Returning Token and Username

- To make our bot work we need to return the `BOT_TOKEN` and `BOT_USERNAME` from the `getBotToken()` and `getbotUsername()` methods.
- And It is necessary to `@Override` these `getBotToken()` and `getBotUsername()` methods.

```java
    @Override
    public String getBotToken() {
        return BOT_TOKEN;
    }

    @Override
    public String getBotUsername() {
        return BOT_USERNAME;
    }
```

### Actual Bot

- After a long time of coding we are now ready to code our **actual bot**.
- So, lets create a method named `onUpdateReceived()` with `Update update` as a parameter and `@Override` it.
- As we know, Our bot will echo back the received text message.
- Lets Start with the following code.

```java
// onUpdateReceived method
@Override
public void onUpdateReceived(Update update) {
  // Checking if the update has message and it has text
  if (update.hasMessage() && update.getMessage().hasText()) {
      // Creating object of SendMessage
      SendMessage message = new SendMessage();
      // Setting chat id
      message.setChatId(update.getMessage().getChatId().toString());
      // Setting reply to message id
      message.setReplyToMessageId(update.getMessage().getMessageId());
      // Getting and setting received message text
      message.setText(update.getMessage().getText());
      try {
        // Sending message
        execute(message);
    } catch (Exception e) {
        e.printStackTrace();
    }
  }
}
```

- And Thats it! Programming part is finished!

### Procfile

- Since We are deploying in Heroku, We need a `Procfile` to tell **How to Build and Run** our app.
- We are going to create this file in root of our project.
- The `Procfile` should look something like this,

```yml
worker: java -Dserver.port=$PORT $JAVA_OPTS -jar target/*.jar
```

- Now We are ready to deploy our bot in cloud.

## Deployment

- If you are new to this, Learn more from [official docs](https://docs.heroku.com?ref=vinuxd.github.io).
- So, Lets start by creating a heroku account.
- Go to dashboard and Click Create new app.
- Navigate to Deploy panel and Connect Github.
- Search for your repository and Click enter.
- On Manual Deploy section, Select the Branch and click Deploy.
- The most awaited final results are comming!
- Go to LOGS and Wait until Build finishes.
- If things gone good? Sit back and relaxx.
- Then go to your telegram bot and send any text and watch it echo back.

## Conclusion

- So, In this blog we developed and deployed a Java telegram bot.
- And Guess What? The example I used here is Open Source! You can get the whole source code in Github. [Click me to grab](https://github.com/VinuXD/EchoBot-Example) and don't forgot to :star:
- In case of any errors, Please [Open a issue on Github](https://github.com/VinuXD/EchoBot-Example/issues).
- Still having doubts? Feel free to reach me in [Telegram](https://t.me/VINUsChat).


I've clearly explained how to build a java telegram and deploy it on heroku.

Building a JAVA Telegram Bot and Deploying in Heroku

We're no strangers to love
You know the rules and so do I
A full commitment's what I'm thinking of
You wouldn't get this from any other guy
I just wanna tell you how I'm feeling
Gotta make you understand
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
We've known each other for so long
Your heart's been aching but you're too shy to say it
Inside we both know what's been going on
We know the game and we're gonna play it
And if you ask me how I'm feeling
Don't tell me you're too blind to see
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
Never gonna give, never gonna give
(Give you up)
We've known each other for so long
Your heart's been aching but you're too shy to say it
Inside we both know what's been going on
We know the game and we're gonna play it
I just wanna tell you how I'm feeling
Gotta make you understand
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye

Life

A Java Telegram bot that provides thirukkural in tamil, english translations with all informations.

Vinu Varsath.

Electrical Engineer and a Hobby musician, with an interest in embedded things and IOT.

⚡ About Me

My Project Works.

📰 Latest Blogs.

Get In Touch.

Vinu Varsath.

.css-2c5djd{color:var(--chakra-colors-displayColor);}Electrical Engineer and a Hobby musician, with an interest in embedded things and IOT.

⚡ About Me

My Project Works.

📰 Latest Blogs.

Get In Touch.

Electrical Engineer and a Hobby musician, with an interest in embedded things and IOT.