[Spring 입문 10] 스프링 DB 접근 기술: 순수 JDBC

• 환경 설정

• build.gradle - jdbc, h2 데이터베이스 관련 라이브러리 추가

implementation 'org.springframework.boot:spring-boot-starter-jdbc'
runtimeOnly 'com.h2database:h2'

 

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• application.properties - 스프링 부트 데이터베이스 연결 설정 추가

spring.datasource.url=jdbc:h2:tcp://localhost/~/test
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa

 

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• 이렇게 JDBC API로 직접 코딩하는 것은 20년 전 이야기이다. 참고만 하고 넘어가자

 

• Jdbc 회원 리포지토리

package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import org.springframework.jdbc.datasource.DataSourceUtils;
import javax.sql.DataSource;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

public class JdbcMemberRepository implements MemberRepository {

 private final DataSource dataSource;
 public JdbcMemberRepository(DataSource dataSource) {
 this.dataSource = dataSource;
 }
 
 
 @Override
 public Member save(Member member) {
 	String sql = "insert into member(name) values(?)";
 	Connection conn = null;
 	PreparedStatement pstmt = null;
 	ResultSet rs = null;
    
 	try {
 	conn = getConnection();
 	pstmt = conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);
 	pstmt.setString(1, member.getName());
 	pstmt.executeUpdate();
 	rs = pstmt.getGeneratedKeys();
    
 	if (rs.next()) {
 	member.setId(rs.getLong(1));
 	} else {
 	throw new SQLException("id 조회 실패");
 	}
 	return member;
    
 	} catch (Exception e) {
 	throw new IllegalStateException(e);
 	} finally {
 	close(conn, pstmt, rs);
 	}
 }
 
 
 @Override
 public Optional<Member> findById(Long id) {
 	String sql = "select * from member where id = ?";
 	Connection conn = null;
 	PreparedStatement pstmt = null;
 	ResultSet rs = null;
    
 	try {
 	conn = getConnection();
 	pstmt = conn.prepareStatement(sql);
 	pstmt.setLong(1, id);
 	rs = pstmt.executeQuery();
    
 	if(rs.next()) {
 	Member member = new Member();
 	member.setId(rs.getLong("id"));
 	member.setName(rs.getString("name"));
 	return Optional.of(member);
 	} else {
 	return Optional.empty();
 	}
 	} catch (Exception e) {
 	throw new IllegalStateException(e);
 	} finally {
 	close(conn, pstmt, rs);
 	}
 }
 
 
 @Override
 public List<Member> findAll() {
 	String sql = "select * from member";
 	Connection conn = null;
 	PreparedStatement pstmt = null;
 	ResultSet rs = null;
 	try {
 	conn = getConnection();
 	pstmt = conn.prepareStatement(sql);
 	rs = pstmt.executeQuery();
 	List<Member> members = new ArrayList<>();
 	while(rs.next()) {
 	Member member = new Member();
 	member.setId(rs.getLong("id"));
 	member.setName(rs.getString("name"));
 	members.add(member);
 	}
 	return members;
    
 	} catch (Exception e) {
 	throw new IllegalStateException(e);
 	} finally {
 	close(conn, pstmt, rs);
 	}
 }
 
 
 @Override
 public Optional<Member> findByName(String name) {
 	String sql = "select * from member where name = ?";
 	Connection conn = null;
 	PreparedStatement pstmt = null;
 	ResultSet rs = null;
 	try {
 	conn = getConnection();
 	pstmt = conn.prepareStatement(sql);
 	pstmt.setString(1, name);
 	rs = pstmt.executeQuery();
 	if(rs.next()) {
 	Member member = new Member();
 	member.setId(rs.getLong("id"));
 	member.setName(rs.getString("name"));
 	return Optional.of(member);
 	}
 	return Optional.empty();
 	} catch (Exception e) {
 	throw new IllegalStateException(e);
 	} finally {
 	close(conn, pstmt, rs);
 	}
 }
 
 private Connection getConnection() {
 	return DataSourceUtils.getConnection(dataSource);
 }
 private void close(Connection conn, PreparedStatement pstmt, ResultSet rs)
{
 try {
 if (rs != null) {
 rs.close();
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 
 try {
 if (pstmt != null) {
 pstmt.close();
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 
 try {
 if (conn != null) {
 close(conn);
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 }
 
 private void close(Connection conn) throws SQLException {
 	DataSourceUtils.releaseConnection(conn, dataSource);
 }
}

 

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• 스프링 설정 변경

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.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);
 }
}

• memberService → memberRepository
  • MemorymemberRepository → memberRepository
  • JdbcmemberRepository → memberRepository
• 스프링 컨테이너에 다음과 같이 설정되었다.
  • memberController → memberService → jdbcmemberRepository

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• 스프링의 DI (Dependencies Injection) → 기존 코드를 전혀 손대지 않고, 설정만으로 구현 클래스를 변경할 수 있다.

 

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회원목록

• 이제 스프링 서버를 다시 실행해도 데이터가 안전하게 저장되어 있다.