[4단계 - Transaction synchronization 적용하기] 시소(이갱민) 미션 제출합니다. (#1236)

egaeng09 · web-flow · commit 2de800528f97 · 2025-11-04T19:03:36.000+09:00
* feat: 동일한 Connection 객체 사용하여 트랜잭션 추가

* chore: Conflict 해결

* feat: TransactionSynchronizationManager 구현

- ThreadLocal을 기반으로 DataSource별 Connection 관리

* feat: UserService 인터페이스 분리 및 구현체 추가

* refactor: Connection 파라미터 제거 및 transaction synchronization 적용

* test: 테스트 코드 반영

* fix: setAutoCommit 위치 변경

* refactor: 트랜잭션 적용 메서드 분리

* style: 컨벤션 통일

* feat: JdbcTemplate 리소스 누수 문제 해결

* feat: unbindResource 트랜잭션 경계 검사 로직 추가

* refactor: 트랜잭션 로직 분리

* fix: 롤백 중 예외 발생 시 최상위 메시지가 고정되던 현상 수정

* refactor: TransactionTemplate.execute 메서드 분리

* refactor: Exception을 Early Throw 하여 else 키워드 제거
diff --git a/app/src/main/java/com/techcourse/dao/UserDao.java b/app/src/main/java/com/techcourse/dao/UserDao.java
@@ -43,18 +43,6 @@ public void update(final User user) {
         );
     }
 
-    public void update(final Connection connection, final User user) {
-        final var sql = "update users set account = ?, password = ?, email = ? where id = ?";
-        jdbcTemplate.update(
-                connection,
-                sql,
-                user.getAccount(),
-                user.getPassword(),
-                user.getEmail(),
-                user.getId()
-        );
-    }
-
     public List<User> findAll() {
         final var sql = "select id, account, password, email from users";
         return jdbcTemplate.query(sql, userRowMapper);
@@ -66,12 +54,6 @@ public Optional<User> findById(final Long id) {
         return Optional.ofNullable(user);
     }
 
-    public Optional<User> findById(final Connection connection, final Long id) {
-        final var sql = "select id, account, password, email from users where id = ?";
-        final User user = jdbcTemplate.queryForObject(connection, sql, userRowMapper, id);
-        return Optional.ofNullable(user);
-    }
-
     public Optional<User> findByAccount(final String account) {
         final var sql = "select id, account, password, email from users where account = ?";
         final User user = jdbcTemplate.queryForObject(sql, userRowMapper, account);
diff --git a/app/src/main/java/com/techcourse/dao/UserHistoryDao.java b/app/src/main/java/com/techcourse/dao/UserHistoryDao.java
@@ -2,7 +2,6 @@
 
 import com.techcourse.domain.UserHistory;
 import com.interface21.jdbc.core.JdbcTemplate;
-import java.sql.Connection;
 
 public class UserHistoryDao {
 
@@ -25,17 +24,4 @@ public void log(final UserHistory userHistory) {
                 userHistory.getCreateBy()
         );
     }
-
-    public void log(final Connection connection, final UserHistory userHistory) {
-        jdbcTemplate.update(
-                connection,
-                LOG_SQL,
-                userHistory.getUserId(),
-                userHistory.getAccount(),
-                userHistory.getPassword(),
-                userHistory.getEmail(),
-                userHistory.getCreatedAt(),
-                userHistory.getCreateBy()
-        );
-    }
 }
diff --git a/app/src/main/java/com/techcourse/service/AppUserService.java b/app/src/main/java/com/techcourse/service/AppUserService.java
@@ -0,0 +1,37 @@
+package com.techcourse.service;
+
+import com.techcourse.dao.UserDao;
+import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.domain.User;
+import com.techcourse.domain.UserHistory;
+import java.util.NoSuchElementException;
+
+public class AppUserService implements UserService {
+
+    private final UserDao userDao;
+    private final UserHistoryDao userHistoryDao;
+
+    public AppUserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
+        this.userDao = userDao;
+        this.userHistoryDao = userHistoryDao;
+    }
+
+    @Override
+    public void insert(final User user) {
+        userDao.insert(user);
+    }
+
+    @Override
+    public User findById(final long id) {
+        return userDao.findById(id)
+                .orElseThrow(NoSuchElementException::new);
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createdBy) {
+        final var user = findById(id);
+        user.changePassword(newPassword);
+        userDao.update(user);
+        userHistoryDao.log(new UserHistory(user, createdBy));
+    }
+}
diff --git a/app/src/main/java/com/techcourse/service/TxUserService.java b/app/src/main/java/com/techcourse/service/TxUserService.java
@@ -0,0 +1,31 @@
+package com.techcourse.service;
+
+import com.interface21.transaction.support.TransactionTemplate;
+import com.techcourse.domain.User;
+import javax.sql.DataSource;
+
+public class TxUserService implements UserService {
+
+    private final UserService userService;
+    private final TransactionTemplate transactionTemplate;
+
+    public TxUserService(final UserService userService, final DataSource dataSource) {
+        this.userService = userService;
+        this.transactionTemplate = new TransactionTemplate(dataSource);
+    }
+
+    @Override
+    public void insert(final User user) {
+        userService.insert(user);
+    }
+
+    @Override
+    public User findById(final long id) {
+        return userService.findById(id);
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createdBy) {
+        transactionTemplate.execute(() -> userService.changePassword(id, newPassword, createdBy));
+    }
+}
diff --git a/app/src/main/java/com/techcourse/service/UserService.java b/app/src/main/java/com/techcourse/service/UserService.java
@@ -1,66 +1,12 @@
 package com.techcourse.service;
 
-import com.interface21.dao.DataAccessException;
-import com.techcourse.dao.UserDao;
-import com.techcourse.dao.UserHistoryDao;
 import com.techcourse.domain.User;
-import com.techcourse.domain.UserHistory;
-import java.sql.Connection;
-import java.sql.SQLException;
-import java.util.NoSuchElementException;
-import javax.sql.DataSource;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-public class UserService {
+public interface UserService {
 
-    private static final Logger log = LoggerFactory.getLogger(UserService.class);
+    void insert(final User user);
 
-    private final UserDao userDao;
-    private final UserHistoryDao userHistoryDao;
-    private final DataSource dataSource;
+    User findById(final long id);
 
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao, final DataSource dataSource) {
-        this.userDao = userDao;
-        this.userHistoryDao = userHistoryDao;
-        this.dataSource = dataSource;
-    }
-
-    public void insert(final User user) {
-        userDao.insert(user);
-    }
-
-    public User findById(final long id) {
-        return userDao.findById(id)
-                .orElseThrow(NoSuchElementException::new);
-    }
-
-    public void changePassword(final long id, final String newPassword, final String createBy) {
-        try (Connection connection = dataSource.getConnection()) {
-            connection.setAutoCommit(false);
-
-            try {
-                final var user = findById(connection, id);
-                user.changePassword(newPassword);
-                userDao.update(connection, user);
-                userHistoryDao.log(connection, new UserHistory(user, createBy));
-
-                connection.commit();
-            } catch (Exception e) {
-                try {
-                    connection.rollback();
-                } catch (SQLException rollbackEx) {
-                    e.addSuppressed(rollbackEx);
-                }
-                throw new DataAccessException("비밀번호 변경 실패", e);
-            }
-        } catch (SQLException e) {
-            throw new DataAccessException("비밀번호 변경 실패", e);
-        }
-    }
-
-    private User findById(final Connection connection, final long id) {
-        return userDao.findById(connection, id)
-                .orElseThrow(NoSuchElementException::new);
-    }
+    void changePassword(final long id, final String newPassword, final String createdBy);
 }
diff --git a/app/src/test/java/com/techcourse/service/MockUserHistoryDao.java b/app/src/test/java/com/techcourse/service/MockUserHistoryDao.java
@@ -4,7 +4,6 @@
 import com.techcourse.domain.UserHistory;
 import com.interface21.dao.DataAccessException;
 import com.interface21.jdbc.core.JdbcTemplate;
-import java.sql.Connection;
 
 public class MockUserHistoryDao extends UserHistoryDao {
 
@@ -16,9 +15,4 @@ public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
     public void log(final UserHistory userHistory) {
         throw new DataAccessException();
     }
-
-    @Override
-    public void log(final Connection connection, final UserHistory userHistory) {
-        throw new DataAccessException();
-    }
 }
diff --git a/app/src/test/java/com/techcourse/service/UserServiceTest.java b/app/src/test/java/com/techcourse/service/UserServiceTest.java
@@ -31,7 +31,8 @@ void setUp() {
     @Test
     void testChangePassword() {
         final var userHistoryDao = new UserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao, DataSourceConfig.getInstance());
+        final var appUserService = new AppUserService(userDao, userHistoryDao);
+        final var userService = new TxUserService(appUserService, DataSourceConfig.getInstance());
 
         final var newPassword = "qqqqq";
         final var createBy = "gugu";
@@ -46,7 +47,8 @@ void testChangePassword() {
     void testTransactionRollback() {
         // 트랜잭션 롤백 테스트를 위해 mock으로 교체
         final var userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao, DataSourceConfig.getInstance());
+        final var appUserService = new AppUserService(userDao, userHistoryDao);
+        final var userService = new TxUserService(appUserService, DataSourceConfig.getInstance());
 
         final var newPassword = "newPassword";
         final var createBy = "gugu";
diff --git a/jdbc/src/main/java/com/interface21/jdbc/core/JdbcTemplate.java b/jdbc/src/main/java/com/interface21/jdbc/core/JdbcTemplate.java
@@ -1,11 +1,12 @@
 package com.interface21.jdbc.core;
 
 import com.interface21.dao.DataAccessException;
+import com.interface21.jdbc.datasource.DataSourceUtils;
+import com.interface21.transaction.support.TransactionSynchronizationManager;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import javax.sql.DataSource;
-import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.util.ArrayList;
@@ -25,18 +26,10 @@ public void update(final String sql, final Object... args) {
         update(sql, ps -> setParameters(ps, args));
     }
 
-    public void update(final Connection connection, final String sql, final Object... args) {
-        update(connection, sql, ps -> setParameters(ps, args));
-    }
-
     public <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final Object... args) {
         return query(sql, rowMapper, ps -> setParameters(ps, args));
     }
 
-    public <T> List<T> query(final Connection connection, final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        return query(connection, sql, rowMapper, ps -> setParameters(ps, args));
-    }
-
     public <T> T queryForObject(final String sql, final RowMapper<T> rowMapper, final Object... args) {
         final List<T> results = query(sql, rowMapper, args);
         if (results.isEmpty()) {
@@ -45,47 +38,34 @@ public <T> T queryForObject(final String sql, final RowMapper<T> rowMapper, fina
         return results.getFirst();
     }
 
-    public <T> T queryForObject(final Connection connection, final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        final List<T> results = query(connection, sql, rowMapper, args);
-        if (results.isEmpty()) {
-            return null;
-        }
-        return results.getFirst();
-    }
-
     private void update(final String sql, final PreparedStatementSetter preparedStatementSetter) {
-        try (final var connection = dataSource.getConnection();
-             final var preparedStatement = connection.prepareStatement(sql)) {
-            preparedStatementSetter.setValues(preparedStatement);
-            preparedStatement.executeUpdate();
-        } catch (final SQLException e) {
-            throw new DataAccessException(e);
-        }
-    }
-
-    private void update(final Connection connection, final String sql, final PreparedStatementSetter preparedStatementSetter) {
+        final boolean hadExistingConnection = DataSourceUtils.hasResource(dataSource);
+        final var connection = DataSourceUtils.getConnection(dataSource);
         try (final var preparedStatement = connection.prepareStatement(sql)) {
             preparedStatementSetter.setValues(preparedStatement);
             preparedStatement.executeUpdate();
         } catch (final SQLException e) {
             throw new DataAccessException(e);
+        } finally {
+            if (!hadExistingConnection) {
+                DataSourceUtils.releaseConnection(connection, dataSource);
+                TransactionSynchronizationManager.unbindResource(dataSource);
+            }
         }
     }
 
     private <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final PreparedStatementSetter preparedStatementSetter) {
-        try (final var connection = dataSource.getConnection();
-             final var preparedStatement = connection.prepareStatement(sql)) {
-            return executeQuery(preparedStatement, rowMapper, preparedStatementSetter);
-        } catch (final SQLException e) {
-            throw new DataAccessException(e);
-        }
-    }
-
-    private <T> List<T> query(final Connection connection, final String sql, final RowMapper<T> rowMapper, final PreparedStatementSetter preparedStatementSetter) {
+        final boolean hadExistingConnection = DataSourceUtils.hasResource(dataSource);
+        final var connection = DataSourceUtils.getConnection(dataSource);
         try (final var preparedStatement = connection.prepareStatement(sql)) {
             return executeQuery(preparedStatement, rowMapper, preparedStatementSetter);
         } catch (final SQLException e) {
             throw new DataAccessException(e);
+        } finally {
+            if (!hadExistingConnection) {
+                DataSourceUtils.releaseConnection(connection, dataSource);
+                TransactionSynchronizationManager.unbindResource(dataSource);
+            }
         }
     }
 
diff --git a/jdbc/src/main/java/com/interface21/jdbc/datasource/DataSourceUtils.java b/jdbc/src/main/java/com/interface21/jdbc/datasource/DataSourceUtils.java
@@ -12,6 +12,10 @@ public abstract class DataSourceUtils {
 
     private DataSourceUtils() {}
 
+    public static boolean hasResource(DataSource dataSource) {
+        return TransactionSynchronizationManager.getResource(dataSource) != null;
+    }
+
     public static Connection getConnection(DataSource dataSource) throws CannotGetJdbcConnectionException {
         Connection connection = TransactionSynchronizationManager.getResource(dataSource);
         if (connection != null) {
diff --git a/jdbc/src/main/java/com/interface21/transaction/support/TransactionSynchronizationManager.java b/jdbc/src/main/java/com/interface21/transaction/support/TransactionSynchronizationManager.java
diff --git a/jdbc/src/main/java/com/interface21/transaction/support/TransactionTemplate.java b/jdbc/src/main/java/com/interface21/transaction/support/TransactionTemplate.java
diff --git a/study/test.mv.db b/study/test.mv.db
