<dependency>
    <groupId>org.b3log</groupId>
    <artifactId>latke-core</artifactId>
    <version>${latke.version}</version>
</dependency>

final Dispatcher.RouterGroup routeGroup = Dispatcher.group();
routeGroup.get("/", helloProcessor::index).
        get("/register", registerProcessor::showRegister).
        post("/register", registerProcessor::register).
        get("/var/{pathVar}", registerProcessor::paraPathVar).
        router().get().post().uri("/greeting").handler(helloProcessor::greeting);

final JSONObject requestJSON = context.requestJSON();

final String remoteAddr = context.remoteAddr();
final String requestURI = context.requestURI();
final Object att = context.attr("name");
final String method = context.method();
context.sendRedirect("https://b3log.org");
final Request request = context.getRequest();
final Response response = context.getResponse();

@Service
public class UserService {

    private static final Logger LOGGER = Logger.getLogger(UserService.class);

    @Inject
    private UserRepository userRepository;

    @Transactional
    public void saveUser(final String name, final int age) {
        final JSONObject user = new JSONObject();
        user.put("name", name);
        user.put("age", age);

        String userId;

        try {
            userId = userRepository.add(user);
        } catch (final RepositoryException e) {
            LOGGER.log(Level.ERROR, "Saves user failed", e);

            // The framework will roll back the transaction after throwing an exception
            throw new IllegalStateException("Saves user failed");
        }

        LOGGER.log(Level.INFO, "Saves a user successfully [userId={0}]", userId);
    }
}

@Repository
public class UserRepository extends AbstractRepository {

    public UserRepository() {
        super("user");
    }
}

public interface Repository {
    String add(final JSONObject jsonObject) throws RepositoryException;
    void update(final String id, final JSONObject jsonObject) throws RepositoryException;
    void remove(final String id) throws RepositoryException;
    void remove(final Query query) throws RepositoryException;
    JSONObject get(final String id) throws RepositoryException;
    long count(final Query query) throws RepositoryException;
}

public JSONObject getByName(final String name) throws RepositoryException {
    return getFirst(new Query().setFilter(new PropertyFilter("name", FilterOperator.EQUAL, name)));
}

new Query().setPage(1, 50)

new Query().addSort("name", SortDirection.DESCENDING);

new Query().select("name", "age");

final List<JSONObject> records = select("SELECT * FROM `user` WHERE `name` = ?", name);