• 스프링 JdbcTemplate
• 환경설정 : 순수 jdbc에서 한 것과 같음
• 순수 jdbc에서 반복 코드를 많이 제거해줌
• SQL은 직접 작성해야함

JdbcTemplateMemberRepository

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;

    @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;
        };
    }
}

• JdbcTemplate은 주입 못받음
• DataSource를 주입받아서 JdbcTemplate 생성할 때 인자로 던짐
• 참고 : 생성자 하나뿐이면 @Autowired 생략 가능 (스프링 빈으로 등록되었을 때)
• jdbcTemplate.query("쿼리문",memberRowMapper(),쿼리 인자); 형태로 사용
• 쿼리 결과를 RowMapper로 감싸줘야함

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

• Optional 로 반환하기 위해 스트림 생성 후 결과함수 findAny() 사용

    @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;
    }

• SimpleJdbcInsert가 insert 쿼리를 알아서 만들어줌

SpringConfig

package hello.hellospring;

import hello.hellospring.repository.JdbcMemberRepository;
import hello.hellospring.repository.JdbcTemplateMemberRepository;
import hello.hellospring.repository.MemberRepository;
import hello.hellospring.repository.MemoryMemberRepository;
import hello.hellospring.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 final 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);
    }
}

• 조립만 바꿔주면 됨