[1단계 - JDBC 라이브러리 구현하기] - 알파카(최휘용) 미션 제출합니다.

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

@@ -1,121 +1,58 @@
 package com.techcourse.dao;
 
-import com.techcourse.domain.User;
+import com.interface21.jdbc.RowMapper;
 import com.interface21.jdbc.core.JdbcTemplate;
+import com.techcourse.domain.User;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.sql.DataSource;
-import java.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.util.List;
-
 public class UserDao {
 
     private static final Logger log = LoggerFactory.getLogger(UserDao.class);
+    private static final RowMapper<User> USER_ROW_MAPPER = (rs, rowNum) -> new User(
+            rs.getLong(1),
+            rs.getString(2),
+            rs.getString(3),
+            rs.getString(4)
+    );
 
-    private final DataSource dataSource;
-
-    public UserDao(final DataSource dataSource) {
-        this.dataSource = dataSource;
-    }
+    private final JdbcTemplate jdbcTemplate;
 
     public UserDao(final JdbcTemplate jdbcTemplate) {
-        this.dataSource = null;
+        this.jdbcTemplate = jdbcTemplate;
     }
 
     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);
+        String sql = "insert into users (account, password, email) values (?, ?, ?)";
 
-            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) {}
-        }
+        jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail());
     }
 
     public void update(final User user) {
-        // todo
+        String sql = "update users set account = ?, password = ?, email = ?";
+
+        jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail());
     }
 
     public List<User> findAll() {
-        // todo
-        return null;
+        String sql = "select id, account, password, email from users";
+        log.debug("query : {}", sql);
+
+        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 = ?";
-
-        Connection conn = null;
-        PreparedStatement pstmt = null;
-        ResultSet rs = null;
-        try {
-            conn = dataSource.getConnection();
-            pstmt = conn.prepareStatement(sql);
-            pstmt.setLong(1, id);
-            rs = pstmt.executeQuery();
+        String sql = "select id, account, password, email from users where id = ?";
+        log.debug("query : {}", sql);
 
-            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) {}
-
-            try {
-                if (conn != null) {
-                    conn.close();
-                }
-            } catch (SQLException ignored) {}
-        }
+        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, id);
     }
 
     public User findByAccount(final String account) {
-        // todo
-        return null;
+        String sql = "select id, account, password, email from users where account = ?";
+        log.debug("query : {}", sql);
+
+        return jdbcTemplate.queryForObject(sql, USER_ROW_MAPPER, account);
     }
 }

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

@@ -1,22 +1,27 @@
 package com.techcourse.dao;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.interface21.jdbc.core.JdbcTemplate;
 import com.techcourse.config.DataSourceConfig;
 import com.techcourse.domain.User;
 import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
+import javax.sql.DataSource;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 class UserDaoTest {
 
     private UserDao userDao;
 
     @BeforeEach
     void setup() {
-        DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
+        DataSource dataSource = DataSourceConfig.getInstance();
+        DatabasePopulatorUtils.execute(dataSource);
+        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
 
-        userDao = new UserDao(DataSourceConfig.getInstance());
+        userDao = new UserDao(jdbcTemplate);
+        jdbcTemplate.update("truncate table users restart identity");
         final var user = new User("gugu", "password", "[email protected]");
         userDao.insert(user);
     }

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

@@ -1,19 +1,19 @@
 package com.techcourse.service;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import com.interface21.dao.DataAccessException;
+import com.interface21.jdbc.core.JdbcTemplate;
 import com.techcourse.config.DataSourceConfig;
 import com.techcourse.dao.UserDao;
 import com.techcourse.dao.UserHistoryDao;
 import com.techcourse.domain.User;
 import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
-import com.interface21.dao.DataAccessException;
-import com.interface21.jdbc.core.JdbcTemplate;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
 @Disabled
 class UserServiceTest {
 

jdbc/src/main/java/com/interface21/jdbc/RowMapper.java

@@ -0,0 +1,9 @@
+package com.interface21.jdbc;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public interface RowMapper<T> {
+
+    T mapRow(ResultSet rs, int rowNum) throws SQLException;
+}

jdbc/src/main/java/com/interface21/jdbc/core/JdbcTemplate.java

@@ -1,10 +1,17 @@
 package com.interface21.jdbc.core;
 
+import com.interface21.dao.DataAccessException;
+import com.interface21.jdbc.RowMapper;
+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 javax.sql.DataSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.sql.DataSource;
-
 public class JdbcTemplate {
 
     private static final Logger log = LoggerFactory.getLogger(JdbcTemplate.class);
@@ -14,4 +21,52 @@ public class JdbcTemplate {
     public JdbcTemplate(final DataSource dataSource) {
         this.dataSource = dataSource;
     }
+
+    public <T> List<T> query(String sql, RowMapper<T> rowMapper, Object... args) {
+        try (Connection conn = dataSource.getConnection();
+             PreparedStatement psmt = conn.prepareStatement(sql)
+        ) {
+            setPreparedStatementParameters(args, psmt);
+            ResultSet rs = psmt.executeQuery();
+
+            return mapResultSetToList(rowMapper, rs);
+        } catch (SQLException e) {
+            throw new DataAccessException(e);
+        }
+    }
+
+    private <T> List<T> mapResultSetToList(RowMapper<T> rowMapper, ResultSet rs) throws SQLException {
+        List<T> result = new ArrayList<>();
+        while (rs.next()) {
+            T element = rowMapper.mapRow(rs, rs.getRow());
+            result.add(element);
+        }
+        return result;
+    }
+
+    private void setPreparedStatementParameters(Object[] args, PreparedStatement psmt) throws SQLException {
+        for (int i = 0; i < args.length; i++) {
+            psmt.setObject(i + 1, args[i]);
+        }
+    }
+
+    public <T> T queryForObject(String sql, RowMapper<T> rowMapper, Object... args) {
+        List<T> result = query(sql, rowMapper, args);
+        if (result.size() != 1) {
+            throw new DataAccessException("조회하려는 데이터가 여러 개입니다.");
+        }
+        return result.get(0);
+    }
+
+    public int update(String sql, Object... args) {
+        try (Connection conn = dataSource.getConnection();
+             PreparedStatement psmt = conn.prepareStatement(sql)
+        ) {
+            setPreparedStatementParameters(args, psmt);
+
+            return psmt.executeUpdate();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
 }

jdbc/src/test/java/com/interface21/jdbc/core/JdbcTemplateTest.java

@@ -1,5 +1,99 @@
 package com.interface21.jdbc.core;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.when;
+
+import com.interface21.dao.DataAccessException;
+import com.interface21.jdbc.RowMapper;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.util.List;
+import javax.sql.DataSource;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
 class JdbcTemplateTest {
+    @Mock
+    private DataSource dataSource;
+    @Mock
+    private Connection connection;
+    @Mock
+    private PreparedStatement preparedStatement;
+    @Mock
+    private ResultSet resultSet;
+
+    private JdbcTemplate jdbcTemplate;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        MockitoAnnotations.openMocks(this);
+        when(dataSource.getConnection()).thenReturn(connection);
+        when(connection.prepareStatement(anyString())).thenReturn(preparedStatement);
+        jdbcTemplate = new JdbcTemplate(dataSource);
+    }
+
+    @DisplayName("여러 데이터를 조회하는 쿼리를 처리한다.")
+    @Test
+    public void query() throws Exception {
+        when(preparedStatement.executeQuery()).thenReturn(resultSet);
+        when(resultSet.next()).thenReturn(true, true, true, false);
+        when(resultSet.getString("name")).thenReturn("이은정", "클로버", "지니아");
+
+        RowMapper<String> rowMapper = (rs, rowNum) -> rs.getString("name");
+
+        List<String> result = jdbcTemplate.query("select name from users", rowMapper);
+
+        assertAll(
+                () -> assertThat(result.size())
+                        .isEqualTo(3),
+                () -> assertThat(result)
+                        .isEqualTo(List.of("이은정", "클로버", "지니아"))
+        );
+    }
+
+    @DisplayName("데이터를 업데이트하는 쿼리를 처리한다.")
+    @Test
+    public void update() throws Exception {
+        when(preparedStatement.executeUpdate()).thenReturn(1);
+
+        int rowsAffected = jdbcTemplate.update("update users set name = ? where id = ?", "클로버지니아", 1);
+
+        assertThat(rowsAffected)
+                .isEqualTo(1);
+    }
+
+    @DisplayName("한 개의 데이터를 조회하는 쿼리를 처리한다.")
+    @Test
+    public void queryForObject() throws Exception {
+        when(preparedStatement.executeQuery()).thenReturn(resultSet);
+        when(resultSet.next()).thenReturn(true, false);
+        when(resultSet.getString("name")).thenReturn("킹로버");
+
+        RowMapper<String> rowMapper = (rs, rowNum) -> rs.getString("name");
+
+        String result = jdbcTemplate.queryForObject("select name from users where id = ?", rowMapper, 1);
+
+        assertThat(result)
+                .isEqualTo("킹로버");
+    }
+
+    @DisplayName("조회하려는 데이터가 여러 개일 경우 예외로 처리한다.")
+    @Test
+    public void queryForObjectFailedWithMultipleResults() throws Exception {
+        when(preparedStatement.executeQuery()).thenReturn(resultSet);
+        when(resultSet.next()).thenReturn(true, true, false);
+
+        RowMapper<String> rowMapper = (rs, rowNum) -> rs.getString("name");
 
+        assertThatThrownBy(() -> jdbcTemplate.queryForObject("select name from users where id = ?", rowMapper, 1))
+                .isInstanceOf(DataAccessException.class)
+                .hasMessage("조회하려는 데이터가 여러 개입니다.");
+    }
 }

study/src/main/resources/schema.sql

@@ -1,5 +1,5 @@
-# mysql 8.0.30부터는 statement.execute()으로 여러 쿼리를 한 번에 실행할 수 없다.
-# 멀티 쿼리 옵션을 url로 전달하도록 수정하는 방법을 찾아서 적용하자.
+-- mysql 8.0.30부터는 statement.execute()으로 여러 쿼리를 한 번에 실행할 수 없다.
+-- 멀티 쿼리 옵션을 url로 전달하도록 수정하는 방법을 찾아서 적용하자.
 CREATE TABLE IF NOT EXISTS users (
     id BIGINT AUTO_INCREMENT PRIMARY KEY,
     account VARCHAR(100) NOT NULL,