Что такое Jira REST API и как с ним работать?

GET    /rest/api/2/issue/{issueKey}          — получить задачу
POST   /rest/api/2/issue                      — создать задачу
PUT    /rest/api/2/issue/{issueKey}           — обновить задачу
DELETE /rest/api/2/issue/{issueKey}           — удалить задачу
POST   /rest/api/2/issue/{issueKey}/transitions — сменить статус
POST   /rest/api/2/search                     — поиск через JQL
GET    /rest/api/2/project                    — список проектов
GET    /rest/api/2/user?accountId=...         — информация о пользователе

@Service
public class JiraIssueService {

    private final RestClient restClient;

    public JiraIssueService(@Value("${jira.base-url}") String baseUrl,
                            @Value("${jira.pat}") String pat) {
        this.restClient = RestClient.builder()
                .baseUrl(baseUrl + "/rest/api/2")
                .defaultHeader("Authorization", "Bearer " + pat)
                .defaultHeader("Content-Type", "application/json")
                .build();
    }

    public String createIssue(String projectKey, String summary, String description) {
        String body = """
                {
                    "fields": {
                        "project": {"key": "%s"},
                        "summary": "%s",
                        "description": "%s",
                        "issuetype": {"name": "Task"}
                    }
                }
                """.formatted(projectKey, summary, description);

        Map<String, Object> response = restClient.post()
                .uri("/issue")
                .body(body)
                .retrieve()
                .body(new ParameterizedTypeReference<>() {});

        return (String) response.get("key");
    }
}

public List<Map<String, Object>> searchIssues(String jql, int maxResults) {
    String body = """
            {
                "jql": "%s",
                "maxResults": %d,
                "fields": ["summary", "status", "assignee"]
            }
            """.formatted(jql, maxResults);

    Map<String, Object> response = restClient.post()
            .uri("/search")
            .body(body)
            .retrieve()
            .body(new ParameterizedTypeReference<>() {});

    return (List<Map<String, Object>>) response.get("issues");
}

public void transitionIssue(String issueKey, String transitionId) {
    String body = """
            {
                "transition": {"id": "%s"}
            }
            """.formatted(transitionId);

    restClient.post()
            .uri("/issue/{issueKey}/transitions", issueKey)
            .body(body)
            .retrieve()
            .toBodilessEntity();
}