Slack Apps로 알림 전송하기

@RestController
public class SampleController {

    private final RestTemplate restTemplate = new RestTemplate();
    private static final String SLACK_WEBHOOK_URL = "URL";

    @PostMapping("/notify")
    public ResponseEntity<Void> notifySlack() {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        String message = "{\"text\":\"Hello, Pete!\"}";
        HttpEntity<String> entity = new HttpEntity<>(message, headers);

        restTemplate.exchange(SLACK_WEBHOOK_URL, HttpMethod.POST, entity, String.class);

        return ResponseEntity.noContent().build();
    }
}

dependencies {  
  implementation('com.slack.api:slack-api-model:1.42.0')
  implementation('com.slack.api:slack-api-client:1.42.0')
}

private List<LayoutBlock> createLayout() {
  HeaderBlock headerBlock = HeaderBlock.builder()
    .text(PlainTextObject.builder().text("Notification Test").emoji(true).build())
    .build();

  SectionBlock sectionBlock1 = SectionBlock.builder()
    .text(MarkdownTextObject.builder().text("Hello *Pete!*").build())
    .build();

  ButtonElement button = ButtonElement.builder()
    .text(PlainTextObject.builder().text("Petefolio").build())
    .url("https://petefolio.xyz")
    .actionId("button-action")
    .build();

  SectionBlock sectionBlock2 = SectionBlock.builder()
    .text(MarkdownTextObject.builder().text("Please Visit this.").build())
    .accessory(button)
    .build();

  return Arrays.asList(headerBlock, sectionBlock1, sectionBlock2);
}

public ResponseEntity<Void> notifySlack() throws IOException {
  Slack slack = Slack.getInstance();

  List<LayoutBlock> blocks = createLayout();

  Payload payload = Payload.builder()
          .blocks(blocks)
          .build();

  slack.send(SLACK_WEBHOOK_URL, payload);
  return ResponseEntity.noContent().build();
}