순수 JDBC

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

▶ application.properties에 스프링부트 데이터베이스 연결 설정 추가

스프링부트 2.4부터는 spring.datasource.username=sa를 꼭 추가해야 함
→ 추가하지 않으면 Wrong user name or password 오류 발생

 

 

plugins {
	id 'org.springframework.boot' version '2.7.2'
	id 'io.spring.dependency-management' version '1.0.12.RELEASE'
	id 'java'
}

group = 'hello'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'

repositories {
	mavenCentral()
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
	implementation 'org.springframework.boot:spring-boot-starter-web'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
	runtimeOnly 'com.h2database:h2'
	implementation 'org.springframework.boot:spring-boot-starter-jdbc'
}

tasks.named('test') {
	useJUnitPlatform()
}

▶ build.gradle 파일에 jdbc와 h2 데이터베이스 관련 라이브러리 추가

 

 

package hello.hellospring.repository;

import hello.hellospring.domain.Member;

import javax.sql.DataSource;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.springframework.jdbc.datasource.DataSourceUtils;

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 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);
    }

    @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);
        }
    }

    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);
    }
}

▶ JDBC 회원 리포지토리 구성

 

 

package hello.hellospring;

import hello.hellospring.repository.JdbcMemberRepository;
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;
import javax.swing.*;

@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);
    }
}

▶ SpringConfig 파일 설정 변경

    → DataSource는 데이터베이스 커넥션을 획득할 때 사용하는 객체

    → 스프링부트는 데이터베이스 커넥션 정보를 바탕으로 DataSource를 생성하고 스프링 빈으로 만들어 두기 때문에 DI를 받을 수 있음

 

 

▶ 두 번째 접속할 때부터는 JDBC URL을 jdbc:h2:tcp://localhost/~/test로 변경해야 에러가 발생하지 않음

 

 

▶ h2 console을 실행해 member 테이블의 전체 데이터 출력

    → 중간에 발생했던 오류로 인해 계속 테스트 했더니 spring2의 ID값이 2가 아닌 34로 출력됨

 

 

▶ localhost:8080/members에 접속하면 h2 데이터베이스에 저장된 값들을 불러옴