[JDBC 라이브러리 구현하기 - 1단계] 헙크(정현승) 미션 제출합니다.

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

@@ -1,121 +1,54 @@
 package com.techcourse.dao;
 
 import com.techcourse.domain.User;
-import org.springframework.jdbc.core.JdbcTemplate;
 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.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.SQLException;
 import java.util.List;
+import java.util.Optional;
 
 public class UserDao {
+    private static final RowMapper<User> USER_ROW_MAPPER = rs -> new User(
+            rs.getLong("id"),
+            rs.getString("account"),
+            rs.getString("password"),
+            rs.getString("email")
+    );
 
-    private static final Logger log = LoggerFactory.getLogger(UserDao.class);
+    private final JdbcTemplate template;
 
-    private final DataSource dataSource;
-
-    public UserDao(final DataSource dataSource) {
-        this.dataSource = dataSource;
-    }
-
-    public UserDao(final JdbcTemplate jdbcTemplate) {
-        this.dataSource = null;
+    public UserDao(final JdbcTemplate template) {
+        this.template = template;
     }
 
     public void insert(final User user) {
         final var sql = "insert into users (account, password, email) values (?, ?, ?)";
-
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-
-            log.debug("query : {}", sql);
-
-            pstmt.setString(1, user.getAccount());
-            pstmt.setString(2, user.getPassword());
-            pstmt.setString(3, user.getEmail());
-            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) {}
-        }
+        template.update(sql, user.getAccount(), user.getPassword(), user.getEmail());
     }
 
     public void update(final User user) {
-        // todo
+        final var sql = "update users set password = ? where id = ?";
+        template.update(sql, user.getPassword(), user.getId());
     }
 
     public List<User> findAll() {
-        // todo
-        return null;
+        final String sql = "select id, account, password, email from users";
+        return template.query(sql, userRowMapper());
     }
 
-    public User findById(final Long id) {
-        final var sql = "select id, account, password, email from users where id = ?";
-
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        ResultSet rs = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-            pstmt.setLong(1, id);
-            rs = pstmt.executeQuery();
-
-            log.debug("query : {}", sql);
-
-            if (rs.next()) {
-                return new User(
-                        rs.getLong(1),
-                        rs.getString(2),
-                        rs.getString(3),
-                        rs.getString(4));
-            }
-            return null;
-        } 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) {}
+    public Optional<User> findById(final Long id) {
+        final String sql = "select id, account, password, email from users where id = ?";
+        return template.queryForObject(sql, userRowMapper(), id);
+    }
 
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {}
-        }
+    public Optional<User> findByAccount(final String account) {
+        final String sql = "select id, account, password, email from users where account = ?";
+        return template.queryForObject(sql, userRowMapper(), account);
     }
 
-    public User findByAccount(final String account) {
-        // todo
-        return null;
+    private RowMapper<User> userRowMapper() {
+        return USER_ROW_MAPPER;
     }
 }

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

@@ -5,6 +5,8 @@
 import com.techcourse.domain.User;
 import com.techcourse.domain.UserHistory;
 
+import java.util.Optional;
+
 public class UserService {
 
     private final UserDao userDao;
@@ -15,7 +17,7 @@ public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
         this.userHistoryDao = userHistoryDao;
     }
 
-    public User findById(final long id) {
+    public Optional<User> findById(final long id) {
         return userDao.findById(id);
     }
 
@@ -24,7 +26,7 @@ public void insert(final User user) {
     }
 
     public void changePassword(final long id, final String newPassword, final String createBy) {
-        final var user = findById(id);
+        final var user = findById(id).orElseThrow(() -> new IllegalArgumentException("해당 유저가 존재하지 않습니다."));
         user.changePassword(newPassword);
         userDao.update(user);
         userHistoryDao.log(new UserHistory(user, createBy));

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

@@ -5,6 +5,7 @@
 import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.springframework.jdbc.core.JdbcTemplate;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -16,7 +17,7 @@ class UserDaoTest {
     void setup() {
         DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
 
-        userDao = new UserDao(DataSourceConfig.getInstance());
+        userDao = new UserDao(new JdbcTemplate(DataSourceConfig.getInstance()));
         final var user = new User("gugu", "password", "[email protected]");
         userDao.insert(user);
     }
@@ -30,15 +31,15 @@ void findAll() {
 
     @Test
     void findById() {
-        final var user = userDao.findById(1L);
+        final var user = userDao.findById(1L).orElseThrow();
 
         assertThat(user.getAccount()).isEqualTo("gugu");
     }
 
     @Test
     void findByAccount() {
         final var account = "gugu";
-        final var user = userDao.findByAccount(account);
+        final var user = userDao.findByAccount(account).orElseThrow();
 
         assertThat(user.getAccount()).isEqualTo(account);
     }
@@ -49,20 +50,20 @@ void insert() {
         final var user = new User(account, "password", "[email protected]");
         userDao.insert(user);
 
-        final var actual = userDao.findById(2L);
+        final var actual = userDao.findById(2L).orElseThrow();
 
         assertThat(actual.getAccount()).isEqualTo(account);
     }
 
     @Test
     void update() {
         final var newPassword = "password99";
-        final var user = userDao.findById(1L);
-        user.changePassword(newPassword);
+        final var user = userDao.findById(1L).orElseThrow();
 
+        user.changePassword(newPassword);
         userDao.update(user);
 
-        final var actual = userDao.findById(1L);
+        final var actual = userDao.findById(1L).orElseThrow();
 
         assertThat(actual.getPassword()).isEqualTo(newPassword);
     }

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

@@ -5,11 +5,11 @@
 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.dao.DataAccessException;
+import org.springframework.jdbc.core.JdbcTemplate;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -39,7 +39,7 @@ void testChangePassword() {
         final var createBy = "gugu";
         userService.changePassword(1L, newPassword, createBy);
 
-        final var actual = userService.findById(1L);
+        final var actual = userService.findById(1L).orElseThrow();
 
         assertThat(actual.getPassword()).isEqualTo(newPassword);
     }
@@ -56,7 +56,7 @@ void testTransactionRollback() {
         assertThrows(DataAccessException.class,
                 () -> userService.changePassword(1L, newPassword, createBy));
 
-        final var actual = userService.findById(1L);
+        final var actual = userService.findById(1L).orElseThrow();
 
         assertThat(actual.getPassword()).isNotEqualTo(newPassword);
     }

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

@@ -1,17 +1,65 @@
 package org.springframework.jdbc.core;
 
-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 final DataSource dataSource;
 
     public JdbcTemplate(final DataSource dataSource) {
         this.dataSource = dataSource;
     }
+
+    public <T> Optional<T> queryForObject(final String sql, final RowMapper<T> rowMapper, Object... args) {
+        try (final Connection conn = dataSource.getConnection();
+             final PreparedStatement pstmt = conn.prepareStatement(sql)) {
+            for (int i = 0; i < args.length; i++) {
+                pstmt.setObject(i + 1, args[i]);
+            }
+            try (final ResultSet rs = pstmt.executeQuery()) {
+                if (rs.next()) {
+                    return Optional.ofNullable(rowMapper.mapRow(rs));
+                }
+                return Optional.empty();
+            }
+        } catch (final SQLException e) {
+            throw new DataAccessException(e);
+        }
+    }
+
+    public <T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException {
+        try (final Connection conn = dataSource.getConnection();
+             final PreparedStatement pstmt = conn.prepareStatement(sql)) {
+            final List<T> result = new ArrayList<>();
+            try (final ResultSet rs = pstmt.executeQuery()) {
+                if (rs.next()) {
+                    result.add(rowMapper.mapRow(rs));
+                }
+                return result;
+            }
+
+        } catch (final SQLException e) {
+            throw new DataAccessException(e);
+        }
+    }
+
+    public int update(final String sql, final Object... args) {
+        try (final Connection conn = dataSource.getConnection();
+             final PreparedStatement pstmt = conn.prepareStatement(sql)) {
+            for (int i = 0; i < args.length; i++) {
+                pstmt.setObject(i + 1, args[i]);
+            }
+            return pstmt.executeUpdate();
+        } catch (final SQLException e) {
+            throw new DataAccessException(e);
+        }
+    }
 }

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

@@ -0,0 +1,13 @@
+package org.springframework.jdbc.core;
+
+import javax.annotation.Nullable;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface RowMapper<T> {
+
+    @Nullable
+    T mapRow(ResultSet rs) throws SQLException;
+
+}