#9 jdbc: checked exeption -> runtime exception

jdbc/src/main/java/com/example/jdbc/repository/MemberRepository.java

@@ -0,0 +1,12 @@
+package com.example.jdbc.repository;
+
+import com.example.jdbc.domain.Member;
+
+import java.sql.SQLException;
+
+public interface MemberRepository {
+    Member save(Member member);
+    Member findById(String memberId);
+    void update(String memberId, int money);
+    void delete(String memberId);
+}

jdbc/src/main/java/com/example/jdbc/repository/MemberRepositoryEx.java

@@ -0,0 +1,15 @@
+package com.example.jdbc.repository;
+
+import com.example.jdbc.domain.Member;
+
+import java.sql.SQLException;
+
+/**
+ * 체크예외는 특정 예외에 종속적인 인터페이스가 되어 버린다.
+ */
+public interface MemberRepositoryEx {
+    Member save(Member member) throws SQLException;
+    Member findById(String memberId) throws SQLException;
+    void update(String memberId, int money) throws SQLException;
+    void delete(String memberId) throws SQLException;
+}

jdbc/src/main/java/com/example/jdbc/repository/MemberRepositoryV4_1.java

@@ -0,0 +1,136 @@
+package com.example.jdbc.repository;
+
+import com.example.jdbc.domain.Member;
+import com.example.jdbc.repository.ex.MyDbException;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+import org.springframework.jdbc.support.JdbcUtils;
+
+import javax.sql.DataSource;
+import java.sql.*;
+import java.util.NoSuchElementException;
+
+/**
+ * 예외 누수 문제 해결
+ * 체크 예외를 런타임 예외로 변경
+ * MemberRepository 인터페이스 사용
+ * throws SQLException 제거
+ */
+@Slf4j
+public class MemberRepositoryV4_1 implements MemberRepository {
+
+    private final DataSource dataSource;
+
+    public MemberRepositoryV4_1(DataSource dataSource) {
+        this.dataSource = dataSource;
+    }
+
+    @Override
+    public Member save(Member member) {
+        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);
+            throw new MyDbException(e);
+        } finally {
+            close(con, pstmt, null);
+        }
+    }
+
+    @Override
+    public Member findById(String memberId) {
+        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 new MyDbException(e);
+        } finally {
+            close(con, pstmt, rs);
+        }
+    }
+
+    @Override
+    public void update(String memberId, int money) {
+        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 result = pstmt.executeUpdate();
+            log.info("resultSize={}", result);
+        } catch (SQLException e) {
+            log.error("db error", e);
+            throw new MyDbException(e);
+        } finally {
+            close(con, pstmt, null);
+        }
+    }
+
+    @Override
+    public void delete(String memberId) {
+        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 new MyDbException(e);
+        } finally {
+            close(con, pstmt, null);
+        }
+    }
+
+    private void close(Connection con, Statement stmt, ResultSet rs) {
+        JdbcUtils.closeResultSet(rs);
+        JdbcUtils.closeStatement(stmt);
+        // 트랜잭션 동기화를 사용하려면 DataSourceUtils 를 사용해야 한다.
+        DataSourceUtils.releaseConnection(con, dataSource);
+    }
+
+    private Connection getConnection() throws SQLException {
+        // 트랜잭션 동기화를 사용하려면 DataSourceUtils 를 사용해야 한다.
+        Connection con = DataSourceUtils.getConnection(dataSource);
+        log.info("get connection={}, class={}", con, con.getClass());
+        return con;
+    }
+}

jdbc/src/main/java/com/example/jdbc/repository/ex/MyDbException.java

@@ -0,0 +1,19 @@
+package com.example.jdbc.repository.ex;
+
+public class MyDbException extends RuntimeException {
+
+    public MyDbException() {
+    }
+
+    public MyDbException(String message) {
+        super(message);
+    }
+
+    public MyDbException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public MyDbException(Throwable cause) {
+        super(cause);
+    }
+}

jdbc/src/main/java/com/example/jdbc/service/MemberServiceV4.java

@@ -0,0 +1,45 @@
+package com.example.jdbc.service;
+
+import com.example.jdbc.domain.Member;
+import com.example.jdbc.repository.MemberRepository;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * 예외 누수 문제 해결
+ * SQLException 제거
+ *
+ * MemberRepository 인터페이스 의존
+ */
+@Slf4j
+public class MemberServiceV4 {
+
+    private final MemberRepository memberRepository;
+
+    public MemberServiceV4(MemberRepository memberRepository) {
+        this.memberRepository = memberRepository;
+    }
+
+    @Transactional
+    public void accountTransfer(String fromId, String toId, int money) {
+
+        bizLogic(fromId, toId, money);
+    }
+
+    private void bizLogic(String fromId, String toId, int money) {
+        Member fromMember = memberRepository.findById(fromId);
+        Member toMember = memberRepository.findById(toId);
+
+        memberRepository.update(fromId, fromMember.getMoney() - money);
+
+        validation(toMember);
+
+        memberRepository.update(toId, toMember.getMoney() + money);
+    }
+
+    private void validation(Member toMember) {
+        if (toMember.getMemberId().equals("ex")) {
+            throw new IllegalStateException("이체중 예외 발생");
+        }
+    }
+}

jdbc/src/test/java/com/example/jdbc/service/MemberServiceV4Test.java

@@ -0,0 +1,118 @@
+package com.example.jdbc.service;
+
+import com.example.jdbc.domain.Member;
+import com.example.jdbc.repository.MemberRepository;
+import com.example.jdbc.repository.MemberRepositoryV4_1;
+import lombok.extern.slf4j.Slf4j;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.aop.support.AopUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+
+import javax.sql.DataSource;
+import java.sql.SQLException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * 예외 누수 문제 해결
+ * SQLException 제거
+ *
+ * MemberRepository 인터페이스 의존
+ */
+@Slf4j
+@SpringBootTest
+class MemberServiceV4Test {
+
+    public static final String MEMBER_A = "memberA";
+    public static final String MEMBER_B = "memberB";
+    public static final String MEMBER_EX = "ex";
+
+    @Autowired
+    private MemberRepository memberRepository;
+    @Autowired
+    private MemberServiceV4 memberService;
+
+    @TestConfiguration
+    static class TestConfig {
+
+        private final DataSource dataSource;
+
+        public TestConfig(DataSource dataSource) {
+            this.dataSource = dataSource;
+        }
+
+        @Bean
+        MemberRepository memberRepository() {
+            return new MemberRepositoryV4_1(dataSource);
+        }
+
+        @Bean
+        MemberServiceV4 memberServiceV4() {
+            return new MemberServiceV4(memberRepository());
+        }
+    }
+
+    @AfterEach
+    void after() {
+        memberRepository.delete(MEMBER_A);
+        memberRepository.delete(MEMBER_B);
+        memberRepository.delete(MEMBER_EX);
+    }
+
+    @Test
+    void AopCheck() {
+        log.info("memberService class={}", memberService.getClass());
+        log.info("memberRepository class={}", memberRepository.getClass());
+
+        Assertions.assertThat(AopUtils.isAopProxy(memberService)).isTrue();
+        Assertions.assertThat(AopUtils.isAopProxy(memberRepository)).isFalse();
+    }
+
+    @Test
+    @DisplayName("정상 이체")
+    void accountTransfer() {
+        // given
+        Member memberA = new Member(MEMBER_A, 10000);
+        Member memberB = new Member(MEMBER_B, 10000);
+        memberRepository.save(memberA);
+        memberRepository.save(memberB);
+
+        // when
+        memberService.accountTransfer(memberA.getMemberId(), memberB.getMemberId(), 2000);
+
+        // then
+        Member findMemberA = memberRepository.findById(memberA.getMemberId());
+        Member findMemberB = memberRepository.findById(memberB.getMemberId());
+
+        assertThat(findMemberA.getMoney()).isEqualTo(8000);
+        assertThat(findMemberB.getMoney()).isEqualTo(12000);
+    }
+
+    @Test
+    @DisplayName("이체중 예외 발생")
+    void accountTransferEx() {
+        // given
+        Member memberA = new Member(MEMBER_A, 10000);
+        Member memberEx = new Member(MEMBER_EX, 10000);
+        memberRepository.save(memberA);
+        memberRepository.save(memberEx);
+
+        // when
+        assertThatThrownBy(() -> memberService.accountTransfer(memberA.getMemberId(), memberEx.getMemberId(), 2000))
+                .isInstanceOf(IllegalStateException.class);
+
+        // then
+        Member findMemberA = memberRepository.findById(memberA.getMemberId());
+        Member findMemberB = memberRepository.findById(memberEx.getMemberId());
+
+        assertThat(findMemberA.getMoney()).isEqualTo(10000);
+        assertThat(findMemberB.getMoney()).isEqualTo(10000);
+    }
+}