[ JDBC 2단계] 박스터 미션 제출합니다.

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

@@ -1,51 +1,49 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.User;
-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;
+import java.util.Optional;
 
 public class UserDao {
 
-    private static final Logger log = LoggerFactory.getLogger(UserDao.class);
     private static final RowMapper<User> USER_ROW_MAPPER = rs -> new User(rs.getLong(1), rs.getString(2), rs.getString(3), rs.getString(4));
 
     private final JdbcTemplate jdbcTemplate;
 
-    public UserDao(final DataSource dataSource) {
+    public UserDao(DataSource dataSource) {
         this.jdbcTemplate = new JdbcTemplate(dataSource);
     }
 
-    public UserDao(final JdbcTemplate jdbcTemplate) {
+    public UserDao(JdbcTemplate jdbcTemplate) {
         this.jdbcTemplate = jdbcTemplate;
     }
 
-    public void insert(final User user) {
-        final var sql = "insert into users (account, password, email) values (?, ?, ?)";
+    public void insert(User user) {
+        var sql = "insert into users (account, password, email) values (?, ?, ?)";
         jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail());
     }
 
-    public void update(final User user) {
-        final var sql = "update users set (account, password, email) = (?, ?, ?) where id = ?";
+    public void update(User user) {
+        var sql = "update users set (account, password, email) = (?, ?, ?) where id = ?";
         jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
     }
 
     public List<User> findAll() {
-        final var sql = "select id, account, password, email from users";
+        var sql = "select id, account, password, email from users";
         return jdbcTemplate.query(sql, USER_ROW_MAPPER);
     }
 
-    public User findById(final Long id) {
-        final var sql = "select id, account, password, email from users where id = ?";
+    public Optional<User> findById(Long id) {
+        var sql = "select id, account, password, email from users where id = ?";
         return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, id);
     }
 
-    public User findByAccount(final String account) {
-        final var sql = "select id, account, password, email from users where account = ?";
+    public Optional<User> findByAccount(String account) {
+        var sql = "select id, account, password, email from users where account = ?";
         return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, account);
 
     }

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

@@ -16,7 +16,8 @@ public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
     }
 
     public User findById(final long id) {
-        return userDao.findById(id);
+        return userDao.findById(id)
+                .orElseThrow(IllegalArgumentException::new);
     }
 
     public void insert(final User user) {

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

@@ -32,15 +32,17 @@ void findAll() {
     void findById() {
         final var user = userDao.findById(1L);
 
-        assertThat(user.getAccount()).isEqualTo("gugu");
+        assertThat(user).isPresent();
+        assertThat(user.get().getAccount()).isEqualTo("gugu");
     }
 
     @Test
     void findByAccount() {
         final var account = "gugu";
         final var user = userDao.findByAccount(account);
 
-        assertThat(user.getAccount()).isEqualTo(account);
+        assertThat(user).isPresent();
+        assertThat(user.get().getAccount()).isEqualTo(account);
     }
 
     @Test
@@ -51,18 +53,19 @@ void insert() {
 
         final var actual = userDao.findById(2L);
 
-        assertThat(actual.getAccount()).isEqualTo(account);
+        assertThat(actual).isPresent();
+        assertThat(actual.get().getAccount()).isEqualTo(account);
     }
 
     @Test
     void update() {
         final var newPassword = "password99";
-        final var user = userDao.findById(1L);
+        final var user = userDao.findById(1L).get();
         user.changePassword(newPassword);
 
         userDao.update(user);
 
-        final var actual = userDao.findById(1L);
+        final var actual = userDao.findById(1L).get();
 
         assertThat(actual.getPassword()).isEqualTo(newPassword);
     }

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

@@ -2,144 +2,69 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.dao.DataAccessException;
 
 import javax.sql.DataSource;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 public class JdbcTemplate {
 
-    private static final Logger log = LoggerFactory.getLogger(JdbcTemplate.class);
+    private static Logger log = LoggerFactory.getLogger(JdbcTemplate.class);
 
     private final DataSource dataSource;
 
-    public JdbcTemplate(final DataSource dataSource) {
+    public JdbcTemplate(DataSource dataSource) {
         this.dataSource = dataSource;
     }
 
-    public void update(String sql, Object... args) {
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-
-            log.debug("query : {}", sql);
-            setValues(pstmt, args);
-            pstmt.executeUpdate();
-        } catch (SQLException e) {
-            log.error(e.getMessage(), e);
-            throw new RuntimeException(e);
-        } finally {
-            try {
-                if (pstmt != null) {
-                    pstmt.close();
-                }
-            } catch (SQLException ignored) {
-            }
+    public int update(String sql, Object... args) {
+        return execute(sql, PreparedStatement::executeUpdate, args);
+    }
 
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {
-            }
-        }
+    public <T> List<T> query(String sql, RowMapper<T> rowMapper, Object... args) {
+        return execute(sql, statement -> fetchData(statement, new RowMapResultSetExecutor<>(rowMapper)), args);
     }
 
-    private void setValues(PreparedStatement pstmt, Object... args) throws SQLException {
-        for (int i = 0; i < args.length; i++) {
-            pstmt.setObject(i + 1, args[i]);
+    public <T> Optional<T> queryForObject(String sql, RowMapper<T> rowMapper, Object... args) {
+        List<T> results = query(sql, rowMapper, args);
+        if (results.size() > 1) {
+            throw new DataAccessException();
         }
+        return Optional.ofNullable(results.get(0));
     }
 
-    public <T> T queryForObject(String sql, RowMapper<T> rowMapper, Object... args) {
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        ResultSet rs = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-            setValues(pstmt, args);
-            rs = pstmt.executeQuery();
-
+    private <T> T execute(String sql, PreparedStatementExecutor<T> executor, Object... args) {
+        try (
+                Connection connection = dataSource.getConnection();
+                PreparedStatement statement = getPreparedStatement(sql, connection, args);
+        ) {
             log.debug("query : {}", sql);
-
-            if (rs.next()) {
-                return rowMapper.mapRow(rs);
-            }
-            return null;
+            return executor.fetchData(statement);
         } catch (SQLException e) {
             log.error(e.getMessage(), e);
-            throw new RuntimeException(e);
-        } finally {
-            try {
-                if (rs != null) {
-                    rs.close();
-                }
-            } catch (SQLException ignored) {
-            }
-
-            try {
-                if (pstmt != null) {
-                    pstmt.close();
-                }
-            } catch (SQLException ignored) {
-            }
-
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {
-            }
+            throw new DataAccessException(e);
         }
     }
 
-    public <T> List<T> query(String sql, RowMapper<T> rowMapper) {
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        ResultSet rs = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-            setValues(pstmt);
-            rs = pstmt.executeQuery();
+    private PreparedStatement getPreparedStatement(String sql, Connection connection, Object... args) throws SQLException {
+        PreparedStatement preparedStatement = connection.prepareStatement(sql);
+        for (int i = 0; i < args.length; i++) {
+            preparedStatement.setObject(i + 1, args[i]);
+        }
+        return preparedStatement;
+    }
 
-            log.debug("query : {}", sql);
-            List<T> results = new ArrayList<>();
-            while (rs.next()) {
-                results.add(rowMapper.mapRow(rs));
-            }
-            return results;
+    private <T> T fetchData(PreparedStatement statement, ResultSetExecutor<T> executor) {
+        try (ResultSet resultSet = statement.executeQuery()) {
+            return executor.extractData(resultSet);
         } catch (SQLException e) {
             log.error(e.getMessage(), e);
-            throw new RuntimeException(e);
-        } finally {
-            try {
-                if (rs != null) {
-                    rs.close();
-                }
-            } catch (SQLException ignored) {
-            }
-
-            try {
-                if (pstmt != null) {
-                    pstmt.close();
-                }
-            } catch (SQLException ignored) {
-            }
-
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {
-            }
+            throw new DataAccessException(e);
         }
     }
 }

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

@@ -0,0 +1,9 @@
+package org.springframework.jdbc.core;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+public interface PreparedStatementExecutor<T> {
+
+    T fetchData(PreparedStatement statement) throws SQLException;
+}

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

@@ -0,0 +1,8 @@
+package org.springframework.jdbc.core;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public interface ResultSetExecutor<T> {
+    T extractData(ResultSet resultSet) throws SQLException;
+}

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

@@ -0,0 +1,24 @@
+package org.springframework.jdbc.core;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+public class RowMapResultSetExecutor<T> implements ResultSetExecutor<List<T>> {
+
+    private final RowMapper<T> rowMapper;
+
+    public RowMapResultSetExecutor(RowMapper<T> rowMapper) {
+        this.rowMapper = rowMapper;
+    }
+
+    @Override
+    public List<T> extractData(ResultSet resultSet) throws SQLException {
+        List<T> results = new ArrayList<>();
+        while (resultSet.next()) {
+            results.add(rowMapper.mapRow(resultSet));
+        }
+        return results;
+    }
+}