Menu

Expand
Rate this page:

Chat with Java and Servlets

We intend to sunset the Programmable Chat API on July 25, 2022 to focus on the next generation of chat: the Twilio Conversations API. Find out about the EOL process. We have also prepared this Migration Guide to assist in the transition from Chat to Conversations.

Ready to implement a chat application using Twilio Programmable Chat Client?

This application allows users to exchange messages through different channels, using the Twilio Programmable Chat API. On this example, we'll show how to use this API capabilities to manage channels and their usages.

Properati built a web and mobile messaging app to help real estate buyers and sellers connect in real time. Learn more here.

For your convenience, we consolidated the source code for this tutorial in a single GitHub repository. Feel free to clone it and tweak as required.

Let's get started!

Generate the Token

In order to create a Twilio Programmable Chat client, you will need an access token. This token holds information about your Twilio Account and Chat API keys.

We generate this token by creating a new AccessToken and providing it with an ChatGrant. With the AccessToken at hand, we can use its method ToJWT() to return its string representation.

        
        
        
        src/main/java/com/twilio/chat/TwilioTokenCreator.java

        Generate an Access Token

        src/main/java/com/twilio/chat/TwilioTokenCreator.java

        We can generate a token, now we need a way for the chat app to get it.

        Token Generation Controller

        Token Generation Controller

        On our controller we expose the endpoint responsible for providing a valid token. Using this parameter:

        • identity: identifies the user itself.

        It uses tokenGenerator.Generate method to get hold of a new token and return it in a JSON format to be used for our client.

              
              
              
              src/main/java/com/twilio/chat/TokenServlet.java

              Token Generation Controller

              src/main/java/com/twilio/chat/TokenServlet.java

              Now that we have a route that generates JWT tokens on demand, let's use this route to initialize our Twilio Chat Client.

              Initialize the Chat Client

              Initialize the Programmable Chat Client

              On our client, we fetch a new Token using a POST request to our endpoint.

              With the token we can create a new Twilio.AccessManager, and initialize our Twilio.Chat.Client.

                    
                    
                    
                    src/main/webapp/js/twiliochat.js

                    Initialize the Chat Client

                    src/main/webapp/js/twiliochat.js

                    Now that we've initialized our Chat Client, lets see how we can get a list of channels.

                    Get the Channel List

                    Get the Channel List

                    After initializing the client, we can call its method getPublicChannelDescriptors to retrieve all visible channels. The method returns a promise which we use to show the list of channels retrieved on the UI.

                          
                          
                          
                          src/main/webapp/js/twiliochat.js

                          Get the Channel List

                          src/main/webapp/js/twiliochat.js

                          Next, we need a default channel.

                          Join the General Channel

                          Join the General Channel

                          This application will try to join a channel called "General Channel" when it starts. If the channel doesn't exist, we'll create one with that name. The scope of this example application will show you how to work only with public channels, but the Programmable Chat client allows you to create private channels and handles invitations.

                          Notice we set a unique name for the general channel as we don't want to create a new general channel every time we start the application.

                                
                                
                                
                                src/main/webapp/js/twiliochat.js

                                Join the General Channel

                                src/main/webapp/js/twiliochat.js

                                Now let's listen for some channel events.

                                Listen to Channel Events

                                Listen to Channel Events

                                Next we listen for channel events. In our case, we're setting listeners to the following events:

                                • messageAdded: When another member sends a message to the channel you are connected to.
                                • typingStarted: When another member is typing a message on the channel that you are connected to.
                                • typingEnded: When another member stops typing a message on the channel that you are connected to.
                                • memberJoined: When another member joins the channel that you are connected to.
                                • memberLeft: When another member leaves the channel that you are connected to.

                                We register a different function to handle each particular event.

                                      
                                      
                                      
                                      src/main/webapp/js/twiliochat.js

                                      Listen to Channel Events

                                      src/main/webapp/js/twiliochat.js

                                      The client emits events as well. Let's see how we can listen to those events as well.

                                      Listen to Client Events

                                      Listen to Client Events

                                      Just like with channels, we can register handlers for events on the Client:

                                      • channelAdded: When a channel becomes visible to the Client.
                                      • channelRemoved: When a channel is no longer visible to the Client.
                                      • tokenExpired: When the supplied token expires.
                                            
                                            
                                            
                                            src/main/webapp/js/twiliochat.js

                                            Listen to Client Events

                                            src/main/webapp/js/twiliochat.js

                                            We've actually got a real chat app going here, but let's make it more interesting with multiple channels.

                                            Create a Channel

                                            Create a Channel

                                            When a user clicks on the "+ Channel" link we'll show an input text field where it's possible to type the name of the new channel. Creating a channel is as simple as calling createChannel with an object that has the friendlyName key. You can create a channel with more options listed on the Channels section of the Programmable Chat documentation.

                                                  
                                                  
                                                  
                                                  src/main/webapp/js/twiliochat.js

                                                  Create a Channel

                                                  src/main/webapp/js/twiliochat.js

                                                  Next, we will see how we can switch between channels.

                                                  Join Other Channels

                                                  Join Other Channels

                                                  When you tap on the name of a channel from the sidebar, that channel is set as the selectedChannel. The selectChannel method takes care of joining to the selected channel and setting up the selectedChannel.

                                                        
                                                        
                                                        
                                                        src/main/webapp/js/twiliochat.js

                                                        Join Other Channels

                                                        src/main/webapp/js/twiliochat.js

                                                        At some point your users will want to delete a channel. Let's have a look at how that can be done.

                                                        Delete a Channel

                                                        Delete a Channel

                                                        Deleting a channel is even more simple than creating one. The application lets the user delete the channel they are currently joined to through the "delete current channel" link. The only thing you need to do to actually delete the channel from Twilio, is call the delete method on the channel you are trying to delete. Like other methods on the Channel object, it'll return a promise where you can set the success handler.

                                                              
                                                              
                                                              
                                                              src/main/webapp/js/twiliochat.js

                                                              Delete a Channel

                                                              src/main/webapp/js/twiliochat.js

                                                              That's it! We've just implemented a simple chat application for Java using the Servlet API.

                                                              Where to Next?

                                                              Where to Next?

                                                              If you are a Java developer working with Twilio, you might want to check out these other tutorials:

                                                              SMS and MMS Notifications

                                                              Never miss another server outage. Learn how to build a server notification system that will alert all administrators via SMS when a server outage occurs.

                                                              Workflow Automation

                                                              Increase your rate of response by automating the workflows that are key to your business. In this tutorial, learn how to build a ready-for-scale automated SMS workflow, for a vacation rental company.

                                                              Masked Phone Numbers

                                                              Protect your users' privacy by anonymously connecting them with Twilio Voice and SMS. Learn how to create disposable phone numbers on-demand, so two users can communicate without exchanging personal information.

                                                              Did this help?

                                                              Thanks for checking out this tutorial! If you have any feedback to share with us, we'd love to hear it. Tweet @twilio to let us know what you think.

                                                              Mario Celi Jeff Linwood David Prothero Kat King Andrei Birjukov Andrew Baker Jose Oliveros Paul Kamp Andres Jaan Tack Jeffrey Linwood
                                                              Rate this page:

                                                              Need some help?

                                                              We all do sometimes; code is hard. Get help now from our support team, or lean on the wisdom of the crowd by visiting Twilio's Community Forums or browsing the Twilio tag on Stack Overflow.

                                                                    
                                                                    
                                                                    

                                                                    Thank you for your feedback!

                                                                    We are always striving to improve our documentation quality, and your feedback is valuable to us. How could this documentation serve you better?

                                                                    Sending your feedback...
                                                                    🎉 Thank you for your feedback!
                                                                    Something went wrong. Please try again.

                                                                    Thanks for your feedback!

                                                                    Refer us and get $10 in 3 simple steps!

                                                                    Step 1

                                                                    Get link

                                                                    Get a free personal referral link here

                                                                    Step 2

                                                                    Give $10

                                                                    Your user signs up and upgrade using link

                                                                    Step 3

                                                                    Get $10

                                                                    1,250 free SMSes
                                                                    OR 1,000 free voice mins
                                                                    OR 12,000 chats
                                                                    OR more