[Spring][혼공] 6. 스프링 DB 접근 기술 - (4) 스프링 JDBC Template

스프링 DB 접근 기술

4. 스프링 JDBC Template

• 순수 JDBC와 동일한 환경 설정이다.
• 스프링 JDBC Template, MyBatis와 같은 라이브러리는 JDBC API에서 본 반복 코드를 대부분 제거해준다.
• 하지만 SQL은 직접 작성해야 한다.

package hello.hello.spring.repository;

import hello.hello.spring.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;

    // 생성자가 하나라면 @Autowired 생략해도 동작한다.
    public JdbcTemplateMemberRepository(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    @Override
    public Member save(Member member) {
        // insert 문을 자동으로 생성해준다.
        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);
        // Optional 맵핑하기 위해 stream().findAny() 처리
        return result.stream().findAny();
    }

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

    @Override
    public List<Member> findAll() {
        return jdbcTemplate.query("select * from member", memberRowMapper());
    }

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

 

package hello.hello.spring;

import hello.hello.spring.repository.JdbcMemberRepository;
import hello.hello.spring.repository.JdbcTemplateMemberRepository;
import hello.hello.spring.repository.MemberRepository;
import hello.hello.spring.repository.MemoryMemberRepository;
import hello.hello.spring.service.MemberService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class SpringConfig {

    private DataSource dataSource;

    @Autowired
    public SpringConfig(DataSource dataSource){
        this.dataSource = dataSource;
    }

    @Bean
    public MemberService memberService() {
        return new MemberService(memberRepository());
    }

    @Bean
    public MemberRepository memberRepository() {
        //return new MemoryMemberRepository();
        //return new JdbcMemberRepository(dataSource);
        return new JdbcTemplateMemberRepository(dataSource);
    }
}