DataSource 적용

MemberRepositoryV1

package hello.jdbc.repository;

import hello.jdbc.connection.DBConnectionUtil;
import hello.jdbc.domain.Member;
import lombok.extern.slf4j.Slf4j;
import org.springframework.jdbc.support.JdbcUtils;

import javax.sql.DataSource;
import java.sql.*;
import java.util.NoSuchElementException;

@Slf4j
public class MemberRepositoryV1 {

    private final DataSource dataSource;

    public MemberRepositoryV1(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public Member save(Member member) throws SQLException {
        String sql = "insert into member(member_id, money) values (?, ?)";

        Connection con = null;
        PreparedStatement pstmt = null;

        try {
            con = getConnection();
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, member.getMemberId());
            pstmt.setInt(2, member.getMoney());
            pstmt.executeUpdate();

            return member;

        } catch (SQLException e) {
            log.error("db error");
            e.printStackTrace();
            throw e;
        } finally {
            close(con, pstmt, null);

        }

    }

    public Member findById(String memberId) throws SQLException {
        String sql = "select * from member where member_id = ?";

        Connection con = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            con = getConnection();
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, memberId);

            rs = pstmt.executeQuery();

            if (rs.next()) {
                Member member = new Member();
                member.setMemberId(rs.getString("member_id"));
                member.setMoney(rs.getInt("money"));
                return member;

            } else {
                throw new NoSuchElementException("member not found memberId=" + memberId);
            }
        } catch (SQLException e) {
            log.error("db error", e);
            throw e;
        } finally {
            close(con, pstmt, rs);
        }
    }

    public void update(String memberId, int money) throws SQLException {
        String sql = "update member set money=? where member_id=?";

        Connection con = null;
        PreparedStatement pstmt = null;

        try {
            con = getConnection();
            pstmt = con.prepareStatement(sql);
            pstmt.setInt(1, money);
            pstmt.setString(2, memberId);
            int resultSize = pstmt.executeUpdate();

            log.info("resultSize = {}", resultSize);


        } catch (SQLException e) {
            log.error("db error", e);
            throw e;
        } finally {
            close(con, pstmt, null);
        }
    }

    public void delete(String memberId) throws SQLException {
        String sql = "delete from member where member_id=?";

        Connection con = null;
        PreparedStatement pstmt = null;

        try {
            con = getConnection();
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, memberId);
            pstmt.executeUpdate();

        } catch (SQLException e) {
            log.error("db error", e);
            throw e;
        } finally {
            close(con, pstmt, null);
        }
    }

    private void close(Connection con, Statement stmt, ResultSet rs) {

        JdbcUtils.closeResultSet(rs);
        JdbcUtils.closeStatement(stmt);
        JdbcUtils.closeConnection(con);

    }

    private Connection getConnection() throws SQLException {

        Connection con = dataSource.getConnection();
        log.info("get connection={}, class={}", con, con.getClass());
        return con;
    }
}

DataSource 의존관계 주입

• 외부에서 DataSource 를 주입 받아서 사용한다. 이제 직접 만든 DBConnectionUtil 을 사용하지 않아도 된다.
• DataSource 는 표준 인터페이스 이기 때문에 DriverManagerDataSource 에서 HikariDataSource 로 변경되어도 해당 코드를 변경하지 않아도 된다.

 

JdbcUtils 편의 메서드

• 스프링은 JDBC를 편리하게 다룰 수 있는 JdbcUtils 라는 편의 메서드를 제공한다.
• JdbcUtils 을 사용하면 커넥션을 좀 더 편리하게 닫을 수 있다

 

 

 

MemberRepositoryV1Test

package hello.jdbc.connection.repository;

import com.zaxxer.hikari.HikariDataSource;
import hello.jdbc.connection.ConnectionConst;
import hello.jdbc.domain.Member;
import hello.jdbc.repository.MemberRepositoryV0;
import hello.jdbc.repository.MemberRepositoryV1;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.NoSuchElementException;

import static hello.jdbc.connection.ConnectionConst.*;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

@Slf4j
class MemberRepositoryV1Test {

    MemberRepositoryV1 repository;

    @BeforeEach
    void beforeEach() {

        //기본 DriverManager - 항상 새로운 커넥션 획득
//        DriverManagerDataSource dataSource = new DriverManagerDataSource(URL, USERNAME, PASSWORD);


        //커넥션 풀링: HikariProxyConnection -> JdbcConnection
        HikariDataSource dataSource = new HikariDataSource();

        dataSource.setJdbcUrl(URL);
        dataSource.setUsername(USERNAME);
        dataSource.setPassword(PASSWORD);

        repository = new MemberRepositoryV1(dataSource);
    }

    @Test
    void crud() throws SQLException, InterruptedException {
        Member member = new Member("memberV101", 10000);
        repository.save(member);

        Member memberById = repository.findById(member.getMemberId());
        assertThat(memberById).isNotNull();

        repository.update(member.getMemberId(), 20000);
        Member updateMember = repository.findById(member.getMemberId());
        assertThat(updateMember.getMoney()).isEqualTo(20000);

        repository.delete(member.getMemberId());
        assertThatThrownBy(() -> repository.findById(member.getMemberId()))
                .isInstanceOf(NoSuchElementException.class);

        Thread.sleep(1000);
    }

}

MemberRepositoryV1 은 DataSource 의존관계 주입이 필요하다.

 

 

 

DriverManagerDataSource 사용

get connection=conn0: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection
get connection=conn1: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection
get connection=conn2: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection
get connection=conn3: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection
get connection=conn4: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection
get connection=conn5: url=jdbc:h2:.. user=SA class=class 
org.h2.jdbc.JdbcConnection

DriverManagerDataSource 를 사용하면 conn0~5 번호를 통해서 항상 새로운 커넥션이 생성되어서 사용되는 것을 확인할 수 있다.

 

 

 

 

HikariDataSource 사용

get connection=HikariProxyConnection@xxxxxxxx1 wrapping conn0: url=jdbc:h2:... 
user=SA
get connection=HikariProxyConnection@xxxxxxxx2 wrapping conn0: url=jdbc:h2:... 
user=SA
get connection=HikariProxyConnection@xxxxxxxx3 wrapping conn0: url=jdbc:h2:... 
user=SA
get connection=HikariProxyConnection@xxxxxxxx4 wrapping conn0: url=jdbc:h2:... 
user=SA
get connection=HikariProxyConnection@xxxxxxxx5 wrapping conn0: url=jdbc:h2:... 
user=SA
get connection=HikariProxyConnection@xxxxxxxx6 wrapping conn0: url=jdbc:h2:... 
user=SA

• 커넥션 풀 사용시 conn0 커넥션이 재사용 된 것을 확인할 수 있다.
• 테스트는 순서대로 실행되기 때문에 커넥션을 사용하고 다시 돌려주는 것을 반복한다. 따라서 conn0 만 사용된다.
• 웹 애플리케이션에 동시에 여러 요청이 들어오면 여러 쓰레드에서 커넥션 풀의 커넥션을 다양하게 가져가는 상황을 확인할 수 있다.

 

 

DI

DriverManagerDataSource > HikariDataSource 로 변경해도 MemberRepositoryV1 의 코드는 전혀 변경하지 않아도 된다. MemberRepositoryV1 는 DataSource 인터페이스에만 의존하기 때문이다.  이것이 DataSource 를 사용하는 장점이다.(DI + OCP)

 

 

 

 

출처 : 김영환 스프링 DB 강의