Companies like Uber, TaskRabbit, and Instacart have built an entire industry around the fact that we, the customers, like to order things instantly wherever we are. The key to those services working? Notifying customers when things change.
In this tutorial, we'll build a notification system for a fake on-demand laundry service Laundr.io using Java and Servlets.
Let's get started! Click the below button to begin.
A driver's screen shows two buttons that allow the laundry delivery person to trigger notifications: one for picking up orders and one for delivering them.
This means we'll have two cases to handle:
- Delivery person picks up laundry to be delivered (
- Delivery person is arriving at the customer's house (
In a production app we would probably trigger the second notification when the delivery person was physically near the customer, using GPS.
(In this case we'll just use a button.)
Let's look at how to use the Twilio REST API Client to send out a notification.
Here we create a helper class with an authenticated Twilio REST API client that we can use anytime we need to send a text message.
Next up, we'll look at how we handle a notification request.
This code handles the HTTP
POST request triggered by the delivery person.
It uses our
MessageSender class to send an SMS message to the customer's phone number, which we have registered in our database. Easy!
Next let's look closer at how we send the SMS.
Here we demonstrate actually sending an SMS or MMS.
Think it needs a picture of the clothes? Good idea.
You can pass along an optional media URL:
In addition to the required parameters (and optional media), we can pass a
StatusCallback url to let us know if the message was delivered.
Message status updates are interesting - let's take a closer look.
Twilio will make a
POST request to this servlet each time our message status changes to one of the following:
We then update this
notificationStatus on the
Order and let the business logic take over. This is a great place to add logic that would resend the message if it failed or send out an automated survey a few minutes after the customer has clothes delivered.
That's a wrap - and a fold! We've just implemented an on-demand notification service that alerts our customers when their order is picked up or arriving.
Next, let's look at some other easy to integrate features.
Java and Twilio go well together! Here are some other Java Servlets tutorials:
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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.
Thanks for checking this tutorial out! Let us know what you've built - or what you're building - on Twitter.