如何使用 Java 从 slack 中读取消息

Question

java.net.ConnectException: invalid_auth

getting this error even after fetching the token for my app

SlackSession session = SlackSessionFactory.createWebSocketSlackSession("token");
        session.connect();
        //ChannelHistoryModule channelHistoryModule = ChannelHistoryModuleFactory.createChannelHistoryModule(session);
        SlackChannel slackChannel=session.findChannelByName("notification-hub-test"); 
        session.sendMessage(slackChannel, "Test Message");
        //List<SlackMessagePosted> messages = channelHistoryModule.fetchHistoryOfChannel(slackChannel.getId(),10);

Answer 1

If you created a Slack bot channel successfully, you should be able to send messages to Slack as follows:

String payload = "{\"text\":\"" + message + "\"}";
Slack slack = Slack.getInstance(); // More on Slack class later
WebhookResponse response = slack.send(WEBHOOK, payload);

At this point, you can do whatever you need to do with the response. At the very least, you should get the response code to see if the message was sent OK. To do that, simply call response.getCode() .

WEBHOOK is the webhook URL for the channel you created.

To get access to the Slack class, you need to import slack-api-client into your project. I use Maven to manage my dependencies. Which, for Slack is

<dependency>
    <groupId>com.slack.api</groupId>
    <artifactId>slack-api-client</artifactId>
    <version>1.10.0</version>
</dependency>