[JDBC 라이브러리 구현하기 - 4단계] 썬샷(오진택) 미션 제출합니다. (#601)

README.md

@@ -8,4 +8,9 @@
 ## 2단계
  - try-with-resources 활용하기
  - 예외 처리 더 신경쓰기
- - 람다 활용해서 코드량 줄이기
+ - 람다 활용해서 코드량 줄이기
+
+## 4단계
+ - Dao의 메서드에서 connection 객체를 파라미터로 전달받지 않기
+ - Connection을 관리하는 기능을 가지는 객체 구현
+ - `UserService`에서 비즈니스 로직과 데이터 액세스 로직 분리하기 

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

@@ -1,15 +1,14 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.User;
-
-import java.sql.Connection;
-import java.util.List;
-import javax.sql.DataSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
 
+import javax.sql.DataSource;
+import java.util.List;
+
 public class UserDao {
 
     private static final Logger log = LoggerFactory.getLogger(UserDao.class);
@@ -34,11 +33,6 @@ public void update(final User user) {
         jdbcTemplate.execute(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
     }
 
-    public void update(final Connection conn, final User user) {
-        final var sql = "update users set account = ?, password = ?, email = ? where id = ?";
-        jdbcTemplate.execute(conn, 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, rowMapper);

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

@@ -6,7 +6,6 @@
 import org.springframework.jdbc.core.JdbcTemplate;
 
 import javax.sql.DataSource;
-import java.sql.Connection;
 
 public class UserHistoryDao {
 
@@ -22,9 +21,9 @@ 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.execute(conn, sql, userHistory.getUserId(), userHistory.getAccount(), userHistory.getPassword(),
+        jdbcTemplate.execute(sql, userHistory.getUserId(), userHistory.getAccount(), userHistory.getPassword(),
                 userHistory.getEmail(), userHistory.getCreatedAt(), userHistory.getCreateBy());
     }
 }

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/TxUserService.java

@@ -0,0 +1,35 @@
+package com.techcourse.service;
+
+import com.techcourse.domain.User;
+import org.springframework.transaction.support.JdbcTransactionManager;
+import org.springframework.transaction.support.TransactionManager;
+
+import javax.sql.DataSource;
+
+public class TxUserService implements UserService {
+
+    private final TransactionManager transactionManager = new JdbcTransactionManager();
+    private final DataSource dataSource;
+    private final UserService userService;
+
+    public TxUserService(DataSource dataSource, UserService userService) {
+        this.dataSource = dataSource;
+        this.userService = userService;
+    }
+
+    @Override
+    public User findById(long id) {
+        return transactionManager.executeAndReturn(dataSource, () -> userService.findById(id));
+    }
+
+    @Override
+    public void insert(User user) {
+        transactionManager.execute(dataSource, () -> userService.insert(user));
+    }
+
+    @Override
+    public void changePassword(long id, String newPassword, String createBy) {
+        transactionManager.execute(dataSource, () -> userService.changePassword(id, newPassword, createBy)
+        );
+    }
+}

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

@@ -1,38 +1,10 @@
 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 org.springframework.transaction.support.TransactionExecutor;
-import org.springframework.transaction.support.TransactionManager;
 
-public class UserService {
+public interface UserService {
 
-    private final UserDao userDao;
-    private final UserHistoryDao userHistoryDao;
-    private final TransactionManager transactionManager = new TransactionExecutor();
-
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
-        this.userDao = userDao;
-        this.userHistoryDao = userHistoryDao;
-    }
-
-    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) {
-        transactionManager.execute(DataSourceConfig.getInstance(), connection -> {
-            final var user = findById(id);
-            user.changePassword(newPassword);
-            userDao.update(connection, user);
-            userHistoryDao.log(connection, new UserHistory(user, createBy));
-        });
-    }
+    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

@@ -5,16 +5,14 @@
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 
-import java.sql.Connection;
-
 public class MockUserHistoryDao extends UserHistoryDao {
 
     public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
         super(jdbcTemplate);
     }
 
     @Override
-    public void log(final Connection connection, final UserHistory userHistory) {
+    public void log(final UserHistory userHistory) {
         throw new DataAccessException();
     }
 }

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

@@ -5,14 +5,10 @@
 import com.techcourse.dao.UserHistoryDao;
 import com.techcourse.domain.User;
 import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
-import org.springframework.dao.DataAccessException;
-import org.springframework.jdbc.core.JdbcTemplate;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
-import org.springframework.transaction.support.TransactionManager;
-
-import java.sql.Connection;
+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;
@@ -36,7 +32,7 @@ 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";
@@ -51,7 +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);
+        final var appUserService = new AppUserService(userDao, userHistoryDao);
+        final var userService = new TxUserService(DataSourceConfig.getInstance(), appUserService);
 
         final var newPassword = "newPassword";
         final var createBy = "gugu";
@@ -63,8 +60,4 @@ void testTransactionRollback() {
 
         assertThat(actual.getPassword()).isNotEqualTo(newPassword);
     }
-
-    private Connection getConnection() {
-        return TransactionManager.getConnection(DataSourceConfig.getInstance());
-    }
 }

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

@@ -2,6 +2,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.jdbc.datasource.DataSourceUtils;
 import org.springframework.jdbc.exception.IncorrectQueryArgumentException;
 import org.springframework.jdbc.exception.IncorrectResultSizeDataAccessException;
 
@@ -27,10 +28,6 @@ public int execute(final String sql, final Object... args) {
         return manageData(PreparedStatement::executeUpdate, sql, args);
     }
 
-    public int execute(final Connection conn, final String sql, final Object... args) {
-        return manageData(conn, PreparedStatement::executeUpdate, sql, args);
-    }
-
     public <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final Object... args) {
         return manageData(pstmt -> {
             try (ResultSet rs = pstmt.executeQuery()) {
@@ -43,18 +40,6 @@ public <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final O
         }, sql, args);
     }
 
-    public <T> List<T> query(final Connection conn, final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        return manageData(conn, pstmt -> {
-            try (ResultSet rs = pstmt.executeQuery()) {
-                final List<T> result = new ArrayList<>();
-                while (rs.next()) {
-                    result.add(rowMapper.mapRow(rs));
-                }
-                return result;
-            }
-        }, sql, args);
-    }
-
     public <T> T queryForObject(final String sql, final RowMapper<T> rowMapper, final Object... args) {
         return manageData(pstmt -> {
             try (ResultSet rs = pstmt.executeQuery()) {
@@ -63,32 +48,16 @@ public <T> T queryForObject(final String sql, final RowMapper<T> rowMapper, fina
         }, sql, args);
     }
 
-    public <T> T queryForObject(final Connection conn, final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        return manageData(conn, pstmt -> {
-            try (ResultSet rs = pstmt.executeQuery()) {
-                return getOneResult(rs, rowMapper);
-            }
-        }, sql, args);
-    }
-
     private <T> T manageData(final PreparedStatementImpl<T> qm, final String sql, final Object... args) {
-        try (Connection conn = dataSource.getConnection();
-             PreparedStatement pstmt = setPreparedStatement(conn, sql, args)) {
-            log.debug("query : {}", sql);
-            return qm.callback(pstmt);
-        } catch (SQLException e) {
-            log.error(e.getMessage(), e);
-            throw new RuntimeException(e);
-        }
-    }
-
-    private <T> T manageData(final Connection conn, final PreparedStatementImpl<T> qm, final String sql, final Object... args) {
+        final Connection conn = DataSourceUtils.getConnection(dataSource);
         try (PreparedStatement pstmt = setPreparedStatement(conn, sql, args)) {
             log.debug("query : {}", sql);
             return qm.callback(pstmt);
         } catch (SQLException e) {
             log.error(e.getMessage(), e);
             throw new RuntimeException(e);
+        } finally {
+            closeConnectionIfAutoCommitted(conn);
         }
     }
 
@@ -126,4 +95,14 @@ private <T> T getOneResult(final ResultSet rs, final RowMapper<T> rowMapper) thr
         }
         throw new IncorrectResultSizeDataAccessException("No result to return");
     }
+
+    private void closeConnectionIfAutoCommitted(Connection conn) {
+        try {
+            if (conn.getAutoCommit()) {
+                DataSourceUtils.releaseConnection(conn, dataSource);
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
 }

jdbc/src/main/java/org/springframework/jdbc/datasource/DataSourceUtils.java

@@ -30,6 +30,7 @@ public static Connection getConnection(DataSource dataSource) throws CannotGetJd
     public static void releaseConnection(Connection connection, DataSource dataSource) {
         try {
             connection.close();
+            TransactionSynchronizationManager.unbindResource(dataSource);
         } catch (SQLException ex) {
             throw new CannotGetJdbcConnectionException("Failed to close JDBC Connection");
         }

jdbc/src/main/java/org/springframework/transaction/support/JdbcTransactionManager.java

@@ -0,0 +1,55 @@
+package org.springframework.transaction.support;
+
+import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+
+public class JdbcTransactionManager implements TransactionManager {
+
+    @Override
+    public void execute(DataSource dataSource, TransactionExecutor method) {
+        final var connection = TransactionManager.getConnection(dataSource);
+        try {
+            connection.setAutoCommit(false);
+            method.execute();
+            connection.commit();
+        } catch (RuntimeException | SQLException e) {
+            handleTransactionException(connection, e);
+        } finally {
+            cleanUpTransaction(dataSource, connection);
+        }
+    }
+
+    @Override
+    public <T> T executeAndReturn(DataSource dataSource, TransactionSupplier<T> method) {
+        final var connection = TransactionManager.getConnection(dataSource);
+        try {
+            connection.setAutoCommit(false);
+            T result = method.get();
+            connection.commit();
+            return result;
+        } catch (RuntimeException | SQLException e) {
+            handleTransactionException(connection, e);
+            return null;
+        } finally {
+            cleanUpTransaction(dataSource, connection);
+        }
+    }
+
+    private static void handleTransactionException(Connection connection, Exception e) {
+        try {
+            connection.rollback();
+            throw new DataAccessException(e);
+        } catch (SQLException rollbackException) {
+            throw new RuntimeException(rollbackException);
+        }
+    }
+
+    private void cleanUpTransaction(DataSource dataSource, Connection connection) {
+        DataSourceUtils.releaseConnection(connection, dataSource);
+        TransactionSynchronizationManager.unbindResource(dataSource);
+    }
+}