[Spring] 김영한 스프링 입문 강의 정리 #20 스프링 DB 접근 기술(스프링 JdbcTemplate)

인프런 스프링 입문 강의 정리 #20 스프링 DB 접근 기술(스프링 JdbcTemplate)

https://www.inflearn.com/course/%EC%8A%A4%ED%94%84%EB%A7%81-%EC%9E%85%EB%AC%B8-%EC%8A%A4%ED%94%84%EB%A7%81%EB%B6%80%ED%8A%B8/dashboard

[무료] 스프링 입문 - 코드로 배우는 스프링 부트, 웹 MVC, DB 접근 기술 - 인프런 | 강의

 

- 스프링 JdbcTemplate

순수 Jdbc와 동일한 환경설정 (spring-boot-starter-jdbc)

스프링 Jdbc Template, MyBatis와 같은 라이브러리는

JDBC API에서 본 반복 코드를 대부분 제거해주지만 SQL은 직접 작성

 

 

- JdbcTemplateMemberRepository.java

Jdbc 코드를 줄여서 만든 것이 Jdbc Template

// JdbcTemplateMemberRepository.java

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.*;

public class JdbcTemplateMemberRepository implements MemberRepository {

    private final JdbcTemplate jdbcTemplate;

    // @Autowired 생성자가 하나이면 생략 가능
    // 스프링이 DataSource 자동으로 인젝션
    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()); // 4줄로 insert문 만듦

        Number key = jdbcInsert.executeAndReturnKey(new MapSqlParameterSource(parameters));
        member.setId(key.longValue());
        return member;
    }

    // Jdbc Template에서 sql 쿼리 보내서 결과 매핑 후 List로 받아서 Optional로 바꿔서 반환
    @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 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());
    }

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

// SpringConfig.java

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 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);
    }
}