[JDBC 라이브러리 구현하기 - 2단계] 이리내(성채연) 미션 제출합니다. (#391)

이리내 안녕하세요! 리뷰가 좀 늦었죠..ㅠㅠ 중복 코드를 제거하려는 노력이 보이는 코드였네요..! 꼼꼼한 테스트까지 굳인데요? 제 의견은 참고만 해주시면 감사하겠습니다! 가독성면에서의 리팩토링은 이리내의 선택이지만 예외처리에 대한 부분은 한번 더 고민해 봐주시면 좋을것 같아요! 이미 훌륭한 코드지만! 고생 많으셨습니다~!

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

@@ -8,16 +8,16 @@
 
 public class UserDao {
 
-    private final JdbcTemplate jdbcTemplate;
-
-    private final RowMapper<User> rowMapper = rs ->
+    private static final RowMapper<User> ROW_MAPPER = rs ->
             new User(
                     rs.getLong("id"),
                     rs.getString("account"),
                     rs.getString("password"),
                     rs.getString("email")
             );
 
+    private final JdbcTemplate jdbcTemplate;
+
     public UserDao(final DataSource dataSource) {
         this.jdbcTemplate = new JdbcTemplate(dataSource);
     }
@@ -38,16 +38,16 @@ public void update(final User user) {
 
     public List<User> findAll() {
         final String sql = "select id, account, password, email from users";
-        return jdbcTemplate.query(sql, rowMapper);
+        return jdbcTemplate.query(sql, ROW_MAPPER);
     }
 
     public User findById(final Long id) {
         final String sql = "select id, account, password, email from users where id = ?";
-        return jdbcTemplate.queryForObject(sql, rowMapper, id);
+        return jdbcTemplate.queryForObject(sql, ROW_MAPPER, id);
     }
 
     public User findByAccount(final String account) {
         final String sql = "select id, account, password, email from users where account = ?";
-        return jdbcTemplate.queryForObject(sql, rowMapper, account);
+        return jdbcTemplate.queryForObject(sql, ROW_MAPPER, account);
     }
 }

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

@@ -1,62 +1,32 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.UserHistory;
-import org.springframework.jdbc.core.JdbcTemplate;
-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 org.springframework.jdbc.core.JdbcTemplate;
 
 public class UserHistoryDao {
 
-    private static final Logger log = LoggerFactory.getLogger(UserHistoryDao.class);
-
-    private final DataSource dataSource;
+    private final JdbcTemplate jdbcTemplate;
 
     public UserHistoryDao(final DataSource dataSource) {
-        this.dataSource = dataSource;
+        this.jdbcTemplate = new JdbcTemplate(dataSource);
     }
 
     public UserHistoryDao(final JdbcTemplate jdbcTemplate) {
-        this.dataSource = null;
+        this.jdbcTemplate = jdbcTemplate;
     }
 
     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) {}
-        }
+        jdbcTemplate.update(
+                sql,
+                userHistory.getUserId(),
+                userHistory.getAccount(),
+                userHistory.getPassword(),
+                userHistory.getEmail(),
+                userHistory.getCreatedAt(),
+                userHistory.getCreateBy()
+        );
     }
 }

app/src/test/java/com/techcourse/dao/UserHistoryDaoTest.java

@@ -0,0 +1,25 @@
+package com.techcourse.dao;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+import com.techcourse.config.DataSourceConfig;
+import com.techcourse.domain.User;
+import com.techcourse.domain.UserHistory;
+import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
+import org.junit.jupiter.api.Test;
+
+class UserHistoryDaoTest {
+
+    private UserHistoryDao userHistoryDao;
+
+    @Test
+    void log() {
+        DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
+
+        userHistoryDao = new UserHistoryDao(DataSourceConfig.getInstance());
+        final User user = new User(1L, "irene", "password", "[email protected]");
+        final UserHistory userHistory = new UserHistory(user, "irene");
+
+        assertThatCode(() -> userHistoryDao.log(userHistory)).doesNotThrowAnyException();
+    }
+}

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

@@ -0,0 +1,10 @@
+package org.springframework.jdbc.core;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface ExecutionCallback<T> {
+
+    T execute(final PreparedStatement preparedStatement) throws SQLException;
+}

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

@@ -19,50 +19,57 @@ public JdbcTemplate(final DataSource dataSource) {
     }
 
     public int update(final String sql, final Object... args) {
+        return execute(connection -> prepareStatement(sql, connection, args), PreparedStatement::executeUpdate);
+    }
+
+    private <T> T execute(final PreparedStatementCallback preparedStatementCallback,
+                         final ExecutionCallback<T> executionCallback) {
         try (final Connection connection = dataSource.getConnection();
-             final PreparedStatement pstmt = connection.prepareStatement(sql)) {
-            setParameters(pstmt, args);
-            return pstmt.executeUpdate();
+             final PreparedStatement pstmt = preparedStatementCallback.prepareStatement(connection)) {
+            return executionCallback.execute(pstmt);
         } catch (SQLException e) {
             throw new DataAccessException(e);
         }
     }
 
-    public void setParameters(final PreparedStatement pstmt, final Object... args) throws SQLException {
+    private PreparedStatement prepareStatement(final String sql, final Connection connection, final Object[] args)
+            throws SQLException {
+        final PreparedStatement pstmt = connection.prepareStatement(sql);
+        setParameters(pstmt, args);
+        return pstmt;
+    }
+
+    private void setParameters(final PreparedStatement pstmt, final Object[] args) throws SQLException {
         for (int i = 0; i < args.length; i++) {
             pstmt.setObject(i + 1, args[i]);
         }
     }
 
     @Nullable
     public <T> T queryForObject(final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        try (final Connection connection = dataSource.getConnection();
-             final PreparedStatement pstmt = connection.prepareStatement(sql)) {
-            setParameters(pstmt, args);
-            try (final ResultSet rs = pstmt.executeQuery()) {
-                if (rs.next()) {
-                    return rowMapper.mapRow(rs);
-                }
-                return null;
-            }
-        } catch (SQLException e) {
-            throw new DataAccessException(e);
+        final List<T> results = executeQuery(connection -> prepareStatement(sql, connection, args), rowMapper);
+        if (results.isEmpty()) {
+            return null;
         }
+        return results.get(0);
     }
 
-    public <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final Object... args) {
-        try (final Connection connection = dataSource.getConnection();
-             final PreparedStatement pstmt = connection.prepareStatement(sql)) {
-            setParameters(pstmt, args);
+    private <T> List<T> executeQuery(
+            final PreparedStatementCallback preparedStatementCallback,
+            final RowMapper<T> rowMapper
+    ) {
+        return execute(preparedStatementCallback, pstmt -> {
             try (final ResultSet rs = pstmt.executeQuery()) {
                 List<T> results = new ArrayList<>();
                 while (rs.next()) {
                     results.add(rowMapper.mapRow(rs));
                 }
                 return results;
             }
-        } catch (SQLException e) {
-            throw new DataAccessException(e);
-        }
+        });
+    }
+
+    public <T> List<T> query(final String sql, final RowMapper<T> rowMapper, final Object... args) {
+        return executeQuery(connection -> prepareStatement(sql, connection, args), rowMapper);
     }
 }

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

@@ -0,0 +1,11 @@
+package org.springframework.jdbc.core;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface PreparedStatementCallback {
+
+    PreparedStatement prepareStatement(final Connection connection) throws SQLException;
+}