[JDBC 라이브러리 구현하기 - 4단계] 히이로(문제웅) 미션 제출합니다. (#569)

* feat: UserService의 changePassword 로직에 트랜잭션 적용

* refactor: SQLExceptionTranslator static화

* feat: DataSourceUtils 클래스를 통한 커넥션 동기화 기능 구현

* feat: AppService와 TxService 분리

* chore: 윈도우용 테스트 설정 변경

* test: 트랜잭션 학습 테스트 진행

* refactor: JdbcTemplate 가변인자 nullable 어노테이션 추가 선언

* refactor: callback 메서드 checked Exception에서 DataAccessException 제거

* refactor: JdbcTemplate update메서드도 executeQuery를 사용하도록 리팩토링

* refactor: JdbcTemplate 메서드 인자 final 선언

* refactor: TxUserService에 템플릿 콜백 패턴 적용

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

@@ -1,7 +1,6 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.User;
-import java.sql.Connection;
 import java.util.List;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
@@ -25,6 +24,7 @@ public void insert(final User user) {
         final var sql = "insert into users (account, password, email) values (?, ?, ?)";
         jdbcTemplate.update(
                 sql,
+                false,
                 user.getAccount(),
                 user.getPassword(),
                 user.getEmail()
@@ -35,18 +35,7 @@ public void update(final User user) {
         String sql = "update users set account = ?, password = ?, email = ? where id = ?";
         jdbcTemplate.update(
                 sql,
-                user.getAccount(),
-                user.getPassword(),
-                user.getPassword(),
-                user.getId()
-        );
-    }
-
-    public void update(final Connection conn, final User user) {
-        String sql = "update users set account = ?, password = ?, email = ? where id = ?";
-        jdbcTemplate.update(
-                conn,
-                sql,
+                false,
                 user.getAccount(),
                 user.getPassword(),
                 user.getPassword(),
@@ -56,16 +45,16 @@ public void update(final Connection conn, final User user) {
 
     public List<User> findAll() {
         String sql = "select id, account, password, email from users";
-        return jdbcTemplate.query(sql, USER_ROW_MAPPER);
+        return jdbcTemplate.query(sql, USER_ROW_MAPPER, false);
     }
 
     public User findById(final Long id) {
         final var sql = "select id, account, password, email from users where id = ?";
-        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, id);
+        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, false, id);
     }
 
     public User findByAccount(final String account) {
         String sql = "select id, account, password, email from users where account = ?";
-        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, account);
+        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, false, account);
     }
 }

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

@@ -1,26 +1,21 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.UserHistory;
-import java.sql.Connection;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class UserHistoryDao {
 
-    private static final Logger log = LoggerFactory.getLogger(UserHistoryDao.class);
-
     private final JdbcTemplate jdbcTemplate;
 
     public UserHistoryDao(final JdbcTemplate jdbcTemplate) {
         this.jdbcTemplate = jdbcTemplate;
     }
 
-    public void log(final Connection conn, final UserHistory userHistory) {
+    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(
-                conn,
                 sql,
+                false,
                 userHistory.getUserId(),
                 userHistory.getAccount(),
                 userHistory.getPassword(),

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

@@ -0,0 +1,35 @@
+package com.techcourse.service;
+
+import com.techcourse.dao.UserDao;
+import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.domain.User;
+import com.techcourse.domain.UserHistory;
+
+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 User findById(final long id) {
+        return userDao.findById(id);
+    }
+
+    @Override
+    public void insert(final User user) {
+        userDao.insert(user);
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createBy) {
+        final var user = findById(id);
+        user.changePassword(newPassword);
+        userDao.update(user);
+        userHistoryDao.log(new UserHistory(user, createBy));
+    }
+}

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

@@ -0,0 +1,9 @@
+package com.techcourse.service;
+
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface TransactionCallback<T> {
+
+    T doInTransaction() throws SQLException;
+}

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

@@ -0,0 +1,83 @@
+package com.techcourse.service;
+
+import com.techcourse.config.DataSourceConfig;
+import com.techcourse.domain.User;
+import java.sql.Connection;
+import java.sql.SQLException;
+import javax.sql.DataSource;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+import org.springframework.jdbc.support.SQLExceptionTranslator;
+
+public class TxUserService implements UserService {
+
+    private final DataSource dataSource;
+    private final UserService userService;
+
+    public TxUserService(UserService userService) {
+        this.dataSource = DataSourceConfig.getInstance();
+        this.userService = userService;
+    }
+
+    @Override
+    public User findById(long id) {
+        TransactionCallback<User> action = () -> userService.findById(id);
+        return doTransactionWithReturn(action);
+    }
+
+    @Override
+    public void insert(User user) {
+        TransactionCallback<Void> action = () -> {
+            userService.insert(user);
+            return null;
+        };
+        doTransactionWithoutReturn(action);
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createBy) {
+        TransactionCallback<Void> action = () -> {
+            userService.changePassword(id, newPassword, createBy);
+            return null;
+        };
+        doTransactionWithoutReturn(action);
+    }
+
+    private <T> T doTransactionWithReturn(TransactionCallback<T> action) {
+        Connection conn = DataSourceUtils.getConnection(dataSource);
+        T result;
+        try {
+            try {
+                conn.setAutoCommit(false);
+                result = action.doInTransaction();
+                conn.commit();
+            } catch (SQLException e) {
+                conn.rollback();
+                throw e;
+            }
+        } catch (SQLException e) {
+            throw SQLExceptionTranslator.translate("", e);
+        } finally {
+            DataSourceUtils.releaseConnection(dataSource);
+        }
+        return result;
+    }
+
+    private <T> void doTransactionWithoutReturn(TransactionCallback<T> action) {
+        Connection conn = DataSourceUtils.getConnection(dataSource);
+        try {
+            try {
+                conn.setAutoCommit(false);
+                action.doInTransaction();
+                conn.commit();
+            } catch (SQLException e) {
+                conn.rollback();
+                throw e;
+            }
+        } catch (SQLException e) {
+            throw SQLExceptionTranslator.translate("", e);
+        } finally {
+            DataSourceUtils.releaseConnection(dataSource);
+        }
+    }
+}
+

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

@@ -1,51 +1,11 @@
 package com.techcourse.service;
 
-import com.techcourse.config.DataSourceConfig;
-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 javax.sql.DataSource;
-import org.springframework.jdbc.support.SQLExceptionTranslator;
 
-public class UserService {
+public interface UserService {
 
-    private final UserDao userDao;
-    private final UserHistoryDao userHistoryDao;
-    private final DataSource dataSource;
-
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
-        this.userDao = userDao;
-        this.userHistoryDao = userHistoryDao;
-        this.dataSource = DataSourceConfig.getInstance();
-    }
-
-    public User findById(final long id) {
-        return userDao.findById(id);
-    }
-
-    public void insert(final User user) {
-        userDao.insert(user);
-    }
-
-    public void changePassword(final long id, final String newPassword, final String createBy) {
-        final var user = findById(id);
-        user.changePassword(newPassword);
-
-        try (final Connection conn = dataSource.getConnection()) {
-            try {
-                conn.setAutoCommit(false);
-                userDao.update(conn, user);
-                userHistoryDao.log(conn, new UserHistory(user, createBy));
-                conn.commit();
-            } catch (SQLException e) {
-                conn.rollback();
-                throw e;
-            }
-        } catch (SQLException e) {
-            throw SQLExceptionTranslator.translate("", e);
-        }
-    }
+    User findById(final long id);
+    void insert(final User user);
+    void changePassword(final long id, final String newPassword, final String createBy);
 }
+

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

@@ -2,7 +2,6 @@
 
 import com.techcourse.dao.UserHistoryDao;
 import com.techcourse.domain.UserHistory;
-import java.sql.Connection;
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 
@@ -13,7 +12,7 @@ public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
     }
 
     @Override
-    public void log(Connection conn, final UserHistory userHistory) {
+    public void log(final UserHistory userHistory) {
         throw new DataAccessException();
     }
 }

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

@@ -31,7 +31,7 @@ void setUp() {
     @Test
     void testChangePassword() {
         final var userHistoryDao = new UserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        final var userService = new AppUserService(userDao, userHistoryDao);
 
         final var newPassword = "qqqqq";
         final var createBy = "gugu";
@@ -46,7 +46,10 @@ void testChangePassword() {
     void testTransactionRollback() {
         // 트랜잭션 롤백 테스트를 위해 mock으로 교체
         final var userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        // 애플리케이션 서비스
+        final var appUserService = new AppUserService(userDao, userHistoryDao);
+        // 트랜잭션 서비스 추상화
+        final var userService = new TxUserService(appUserService);
 
         final var newPassword = "newPassword";
         final var createBy = "gugu";