JdbcCourseRepository.java

package nextstep.courses.infrastructure;

import nextstep.courses.domain.Course;
import nextstep.courses.domain.CourseRepository;
import nextstep.courses.infrastructure.exception.DbInsertFailException;
import nextstep.qna.CannotDeleteException;
import org.springframework.jdbc.core.JdbcOperations;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;

import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.time.LocalDateTime;

@Repository("courseRepository")
public class JdbcCourseRepository implements CourseRepository {
    private JdbcOperations jdbcTemplate;

    public JdbcCourseRepository(JdbcOperations jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    @Override
    public long save(Course course) {
        String sql = "insert into course (title, creator_id, created_at) values(?, ?, ?)";
        KeyHolder keyHolder = new GeneratedKeyHolder();

        jdbcTemplate.update(connection -> {
            PreparedStatement ps = connection.prepareStatement(sql, new String[]{"id"});
            ps.setString(1, course.getTitle());
            ps.setLong(2, course.getCreatorId());
            ps.setTimestamp(3, Timestamp.valueOf(course.getCreatedAt()));
            return ps;
        }, keyHolder);

        if (keyHolder.getKey() == null) {
            throw new DbInsertFailException("Course");
        }
        return keyHolder.getKey().longValue();
    }

    @Override
    public Course findById(Long id) {
        String sql = "select id, title, creator_id, created_at, updated_at from course where id = ?";
        RowMapper<Course> rowMapper = (rs, rowNum) -> new Course(
                rs.getLong(1),
                rs.getString(2),
                rs.getLong(3),
                toLocalDateTime(rs.getTimestamp(4)),
                toLocalDateTime(rs.getTimestamp(5)));
        return jdbcTemplate.queryForObject(sql, rowMapper, id);
    }

    private LocalDateTime toLocalDateTime(Timestamp timestamp) {
        if (timestamp == null) {
            return null;
        }
        return timestamp.toLocalDateTime();
    }
}