6. SpringBoot 입문 - Spring DB 접근 기술 - Spring JdbcTemplate

1. H2 데이터베이스 설치
2. 순수 JDBC
3. Spring 통합 테스트
4. Spring JdbcTemplate
5. JPA
6. Spring Data JPA (JPA를 더 편리하게)

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4. Spring JdbcTemplate

Spring JdbcTemplate은 순수 Jdbc와 동일한 환경설정을 따릅니다. JdbcTemplate과 MyBatis 같은 라이브러리는 JDBC API에서의 반복적인 코드를 대부분 제거해줍니다. 하지만 SQL은 직접 작성해야 합니다.

 

repository/JdbcTemplateMemberRepository

package hello.hellospring.repository;

import hello.hellospring.domain.Member;
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;
    
    @Autowired
    public JdbcTemplateMemberRepository(DataSource dataSource) {
        jdbcTemplate = new JdbcTemplate(dataSource);
    }
    
    @Override
    public Member save(Member member) {
        SimpleJdbcInsert jdbcInsert = new SimpleJdbcInsert(jdbcTemplate);
        jdbcInsert.withTableName("member").usingGeneratedKeyColumns("id");

        Map<String, Object> parameters = new HashMap<>();
        parameters.put("name", member.getName());
        
        Number key = jdbcInsert.executeAndReturnKey(new 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(); 
    }

    @Override
    public List<Member> findAll() {
        return jdbcTemplate.query("select * from member", memberRowMapper());
    }
    
    @Override
    public Optional<Member> findByName(String name) {
        List<Member> result = jdbcTemplate.query("select * from member where name = ?", memberRowMapper(), name);
        return result.stream().findAny();
    }

    private RowMapper<Member> memberRowMapper() { 
        return (rs, rowNum) -> {
            Member member = new Member(); 
            member.setId(rs.getLong("id")); 
            member.setName(rs.getString("name")); 
            return member;
        }; 
    }
}

쿼리의 결과를 RowMapper로 Mapping 해줘야 합니다.

SpringConfig에서는 memberRepository() 메소드를 return new JdbcTemplateMemberRepository(dataSource); 로 수정해줍니다.