This example uses the twitter4j library for Java. You can find the JavaDoc here. Be warned, some of the example code is outdated - you might have to do some Googling.
To install, you can grab the Maven snippet from the homepage linked above or download the source which includes .jar files you can add to your classpath (depends on your specific IDE).
This code assumes your API keys are stored in the following environment variables:
TWITTERBOT_CONSUMER_KEYTWITTERBOT_CONSUMER_SECRETTWITTERBOT_ACCESS_TOKENTWITTERBOT_ACCESS_SECRET
You can also modify this section to read your keys from a file, database, or some other source - just don't push them to your public repo!
After logging in, the script creates an ArrayList:
ArrayList<String> triggerWords = new ArrayList<String>();
triggerWords.add("@" + bot.getScreenName());Any strings you put into this ArrayList will be tracked by twitter4j, which will trigger a function we're going to implement whenever a Tweet is posted containing any of those words. The bot's handle is included by default to respond to mentions.
The function that gets fired is StatusListener.onStatus(). We create a TwitterStream to stream new Tweets, then attach a new StatusListener object where we implement onStatus.
It takes a single argument, status, which contains info about the Tweet. Important to us is the following:
status.getText()- the message textstatus.getUser().getScreenName()- the person's @username
The new function analyzes the Tweet text (in this case, checking if it contains "hi" or "hello") and creates a variable reply containing the reply, then sends the Tweet with twitter.updateStatus().