[JDBC 라이브러리 구현하기 - 3단계] 베베(최원용) 미션 제출합니다. (#483)

* refactor: MySqlDao -> JdbcDao

* feat: 트랜잭션 구현

* refactor: PreparedStatement 메모리 누수 방지

* feat: 트랜잭션 commit, rollback 후처리 메서드 구현

* refactor: Transactional과 TransactionManager 통합

app/src/main/java/com/techcourse/dao/MySqlUserDao.java → app/src/main/java/com/techcourse/dao/JdbcUserDao.java

@@ -7,7 +7,7 @@
 import java.util.List;
 import java.util.Optional;
 
-public class MySqlUserDao implements UserDao {
+public class JdbcUserDao implements UserDao {
 
     private static final RowMapper<User> USER_ROW_MAPPER = resultSet -> {
         final long userId = resultSet.getLong("id");
@@ -19,7 +19,7 @@ public class MySqlUserDao implements UserDao {
 
     private final JdbcTemplate jdbcTemplate;
 
-    public MySqlUserDao(final JdbcTemplate jdbcTemplate) {
+    public JdbcUserDao(final JdbcTemplate jdbcTemplate) {
         this.jdbcTemplate = jdbcTemplate;
     }
 

app/src/main/java/com/techcourse/dao/JdbcUserHistoryDao.java

@@ -0,0 +1,34 @@
+package com.techcourse.dao;
+
+import com.techcourse.domain.UserHistory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.jdbc.core.JdbcTemplate;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+public class JdbcUserHistoryDao implements UserHistoryDao {
+
+    private final JdbcTemplate jdbcTemplate;
+
+    public JdbcUserHistoryDao(JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+    @Override
+    public void log(final UserHistory userHistory) {
+        final var sql = "insert into user_history (user_id, account, password, email, created_at, created_by) values (?, ?, ?, ?, ?, ?)";
+        jdbcTemplate.update(sql,
+                userHistory.getUserId(),
+                userHistory.getAccount(),
+                userHistory.getPassword(),
+                userHistory.getEmail(),
+                userHistory.getCreatedAt(),
+                userHistory.getCreateBy()
+        );
+    }
+
+}

app/src/main/java/com/techcourse/dao/UserHistoryDao.java

@@ -1,62 +1,9 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.UserHistory;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.springframework.jdbc.core.JdbcTemplate;
 
-import javax.sql.DataSource;
-import java.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+public interface UserHistoryDao {
 
-public class UserHistoryDao {
+    void log(final UserHistory userHistory);
 
-    private static final Logger log = LoggerFactory.getLogger(UserHistoryDao.class);
-
-    private final DataSource dataSource;
-
-    public UserHistoryDao(final DataSource dataSource) {
-        this.dataSource = dataSource;
-    }
-
-    public UserHistoryDao(final JdbcTemplate jdbcTemplate) {
-        this.dataSource = null;
-    }
-
-    public void log(final UserHistory userHistory) {
-        final var sql = "insert into user_history (user_id, account, password, email, created_at, created_by) values (?, ?, ?, ?, ?, ?)";
-
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-
-            log.debug("query : {}", sql);
-
-            pstmt.setLong(1, userHistory.getUserId());
-            pstmt.setString(2, userHistory.getAccount());
-            pstmt.setString(3, userHistory.getPassword());
-            pstmt.setString(4, userHistory.getEmail());
-            pstmt.setObject(5, userHistory.getCreatedAt());
-            pstmt.setString(6, userHistory.getCreateBy());
-            pstmt.executeUpdate();
-        } catch (SQLException e) {
-            log.error(e.getMessage(), e);
-            throw new RuntimeException(e);
-        } finally {
-            try {
-                if (pstmt != null) {
-                    pstmt.close();
-                }
-            } catch (SQLException ignored) {}
-
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {}
-        }
-    }
 }

app/src/main/java/com/techcourse/domain/UserHistory.java

@@ -1,5 +1,6 @@
 package com.techcourse.domain;
 
+import java.sql.Connection;
 import java.time.LocalDateTime;
 
 public class UserHistory {

app/src/main/java/com/techcourse/repository/UserRepository.java

@@ -3,6 +3,7 @@
 import com.techcourse.dao.UserDao;
 import com.techcourse.domain.User;
 
+import java.sql.Connection;
 import java.util.List;
 
 public class UserRepository {

app/src/main/java/com/techcourse/service/UserService.java

@@ -1,19 +1,24 @@
 package com.techcourse.service;
 
 import com.techcourse.dao.UserDao;
-import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.dao.JdbcUserHistoryDao;
 import com.techcourse.domain.User;
 import com.techcourse.domain.UserHistory;
 import com.techcourse.repository.UserRepository;
+import org.springframework.jdbc.transaction.TransactionManager;
+
+import javax.sql.DataSource;
 
 public class UserService {
 
+    private final TransactionManager transactionManager;
     private final UserRepository userRepository;
-    private final UserHistoryDao userHistoryDao;
+    private final JdbcUserHistoryDao jdbcUserHistoryDao;
 
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
+    public UserService(final DataSource dataSource, final UserDao userDao, final JdbcUserHistoryDao jdbcUserHistoryDao) {
+        this.transactionManager = new TransactionManager(dataSource);
         this.userRepository = new UserRepository(userDao);
-        this.userHistoryDao = userHistoryDao;
+        this.jdbcUserHistoryDao = jdbcUserHistoryDao;
     }
 
     public User findById(final long id) {
@@ -25,9 +30,12 @@ public void insert(final User user) {
     }
 
     public void changePassword(final long id, final String newPassword, final String createBy) {
-        final var user = findById(id);
-        user.changePassword(newPassword);
-        userRepository.update(user);
-        userHistoryDao.log(new UserHistory(user, createBy));
+        transactionManager.execute(connection -> {
+            final var user = findById(id);
+            user.changePassword(newPassword);
+            userRepository.update(user);
+            jdbcUserHistoryDao.log(new UserHistory(user, createBy));
+            return null;
+        });
     }
 }

app/src/test/java/com/techcourse/dao/MySqlUserDaoTest.java → app/src/test/java/com/techcourse/dao/JdbcUserDaoTest.java

@@ -9,15 +9,15 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-class MySqlUserDaoTest {
+class JdbcUserDaoTest {
 
     private UserDao userDao;
 
     @BeforeEach
     void setup() {
         DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
         JdbcTemplate jdbcTemplate = new JdbcTemplate(DataSourceConfig.getInstance());
-        userDao = new MySqlUserDao(jdbcTemplate);
+        userDao = new JdbcUserDao(jdbcTemplate);
         final User user = new User("gugu", "password", "[email protected]");
         userDao.insert(user);
     }

app/src/test/java/com/techcourse/service/MockUserHistoryDao.java → app/src/test/java/com/techcourse/service/MockJdbcUserHistoryDao.java

@@ -1,13 +1,13 @@
 package com.techcourse.service;
 
-import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.dao.JdbcUserHistoryDao;
 import com.techcourse.domain.UserHistory;
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 
-public class MockUserHistoryDao extends UserHistoryDao {
+public class MockJdbcUserHistoryDao extends JdbcUserHistoryDao {
 
-    public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
+    public MockJdbcUserHistoryDao(final JdbcTemplate jdbcTemplate) {
         super(jdbcTemplate);
     }
 

app/src/test/java/com/techcourse/service/UserServiceTest.java

@@ -1,29 +1,28 @@
 package com.techcourse.service;
 
 import com.techcourse.config.DataSourceConfig;
-import com.techcourse.dao.MySqlUserDao;
-import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.dao.JdbcUserDao;
+import com.techcourse.dao.JdbcUserHistoryDao;
+import com.techcourse.dao.UserDao;
 import com.techcourse.domain.User;
 import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-@Disabled
 class UserServiceTest {
 
     private JdbcTemplate jdbcTemplate;
-    private MySqlUserDao userDao;
+    private UserDao userDao;
 
     @BeforeEach
     void setUp() {
         this.jdbcTemplate = new JdbcTemplate(DataSourceConfig.getInstance());
-        this.userDao = new MySqlUserDao(jdbcTemplate);
+        this.userDao = new JdbcUserDao(jdbcTemplate);
 
         DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
         final var user = new User("gugu", "password", "[email protected]");
@@ -32,8 +31,8 @@ void setUp() {
 
     @Test
     void testChangePassword() {
-        final var userHistoryDao = new UserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        final var userHistoryDao = new JdbcUserHistoryDao(jdbcTemplate);
+        final var userService = new UserService(DataSourceConfig.getInstance(), userDao, userHistoryDao);
 
         final var newPassword = "qqqqq";
         final var createBy = "gugu";
@@ -47,8 +46,8 @@ void testChangePassword() {
     @Test
     void testTransactionRollback() {
         // 트랜잭션 롤백 테스트를 위해 mock으로 교체
-        final var userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        final var userHistoryDao = new MockJdbcUserHistoryDao(jdbcTemplate);
+        final var userService = new UserService(DataSourceConfig.getInstance(), userDao, userHistoryDao);
 
         final var newPassword = "newPassword";
         final var createBy = "gugu";

jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java

@@ -1,5 +1,7 @@
 package org.springframework.jdbc.core;
 
+import org.springframework.jdbc.transaction.TransactionManager;
+
 import javax.sql.DataSource;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
@@ -12,10 +14,10 @@
 
 public class JdbcTemplate {
 
-    private final DataSource dataSource;
+    private final TransactionManager transactionManager;
 
     public JdbcTemplate(final DataSource dataSource) {
-        this.dataSource = dataSource;
+        this.transactionManager = new TransactionManager(dataSource);
     }
 
     public int update(final String sql, final Object... conditions) {
@@ -41,10 +43,10 @@ private <T> T getRowByQuery(final PreparedStatement preparedStatement, final Row
     }
 
     private <T> T getResult(final PreparedStatementExecutor<T> executor, final String sql, final Object... conditions) {
-        PreparedStatement preparedStatement = null;
-        try {
-            Connection connection = dataSource.getConnection();
-            preparedStatement = connection.prepareStatement(sql);
+        Connection connection = transactionManager.getConnection();
+        try (
+                PreparedStatement preparedStatement = connection.prepareStatement(sql);
+        ) {
             setConditions(preparedStatement, conditions);
             return executor.query(preparedStatement);
         } catch (SQLException e) {

jdbc/src/main/java/org/springframework/jdbc/transaction/TransactionExecutor.java

@@ -0,0 +1,9 @@
+package org.springframework.jdbc.transaction;
+
+import java.sql.Connection;
+
+public interface TransactionExecutor<T> {
+
+    T execute(final Connection connection);
+
+}

jdbc/src/main/java/org/springframework/jdbc/transaction/TransactionManager.java

@@ -0,0 +1,80 @@
+package org.springframework.jdbc.transaction;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+
+public class TransactionManager {
+
+    private static final ThreadLocal<Connection> connectionInThread = new ThreadLocal<>();
+
+    private final DataSource dataSource;
+
+    public TransactionManager(DataSource dataSource) {
+        this.dataSource = dataSource;
+    }
+
+    public <T> T execute(final TransactionExecutor<T> transactionExecutor) {
+        try {
+            Connection connection = begin();
+            T response = transactionExecutor.execute(connection);
+            commit();
+            return response;
+        } catch (RuntimeException e) {
+            rollback();
+            throw e;
+        }
+    }
+
+    public Connection begin() {
+        Connection connection = getConnection();
+        try {
+            connection.setAutoCommit(false);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        connectionInThread.set(connection);
+        return connection;
+    }
+
+    public void commit() {
+        Connection connection = getConnection();
+        try {
+            connection.commit();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        init(connection);
+    }
+
+    public void rollback() {
+        Connection connection = getConnection();
+        try {
+            connection.rollback();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        init(connection);
+    }
+
+    private void init(final Connection connection) {
+        try {
+            connection.close();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        connectionInThread.remove();
+    }
+
+    public Connection getConnection() {
+        if (connectionInThread.get() == null) {
+            try {
+                return dataSource.getConnection();
+            } catch (SQLException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return connectionInThread.get();
+    }
+
+}