김영한님의 스프링 입문 - 코드로 배우는 스프링 부트, 웹 MVC, DB 접근 기술을 보면서 공부한 내용입니다.
package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.simple.SimpleJdbcInsert;
import javax.sql.DataSource;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
public class JdbcTemplateMemberRepository implements MemberRepository{
private final JdbcTemplate jdbcTemplate; // 주입받을 수 있는 것은 아니다
// @Autowired 생성자가 한개만 있으면 @Autowired를 생략할 수 있다.
public JdbcTemplateMemberRepository(DataSource dataSource) { // datasource를 주입받는다.
this.jdbcTemplate = new JdbcTemplate(dataSource);
}
@Override
public Member save(Member member) throws SQLException {
SimpleJdbcInsert jdbcInsert = new SimpleJdbcInsert(jdbcTemplate);
// insert문을 만들어줌
jdbcInsert.withTableName("member").usingGeneratedKeyColumns("id");
// member : 테이블명, id : 넣고자하는 키
Map<String, Object> parameters = new HashMap<>();
parameters.put("name", member.getName());
Number key = jdbcInsert.executeAndReturnKey(new // executeAndReturnKey를 통해 member를 받고 setId로 값을 넣어준다
MapSqlParameterSource(parameters));
member.setId(key.longValue());
return member;
}
@Override
public Optional<Member> findById(Long id) {
List<Member> result = jdbcTemplate.query("select * from member where id = ?", memberRowMapper(), id);
return result.stream().findAny(); // Optional로 반환
}
@Override
public Optional<Member> findByName(String name) {
List<Member> result = jdbcTemplate.query("select * from member where name = ?", memberRowMapper(), name);
return result.stream().findAny(); // Optional로 반환
}
@Override
public List<Member> findAll() {
return jdbcTemplate.query("select * from member", memberRowMapper());
}
/*
RowMapper란?
-> 데이터베이스의 반환 결과인 ResultSet을 객체로 변환해주는 클래스
*/
/*
private RowMapper<Member> memberRowMapper(){
return new RowMapper<Member>() {
@Override
public Member mapRow(ResultSet rs, int rowNum) throws SQLException {
// ResultSet 값을 Member 객체에 저장
Member member = new Member();
member.setId(rs.getLong("id"));
member.setName(rs.getString("name"));
// member 반환
return member;
};
};
}
*/
// 람다식으로 변경 가능
private RowMapper<Member> memberRowMapper(){
return (rs, rowNum) -> {
// ResultSet 값을 Member 객체에 저장
Member member = new Member();
member.setId(rs.getLong("id"));
member.setName(rs.getString("name"));
// member 반환
return member;
};
}
}
@Bean
public MemberRepository memberRepository() {
// return new MemoryMemberRepository();
// return new JdbcMemberRepository(dataSource);
return new JdbcTemplateMemberRepository(dataSource);
}