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[JDBC 라이브러리 구현하기 - 4단계] 하마드(이건회) 미션 제출합니다. #538

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merged 6 commits into from
Oct 12, 2023
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[JDBC 라이브러리 구현하기 - 4단계] 하마드(이건회) 미션 제출합니다. #538

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f4e8aa3
feat: 트랜잭션 동기화 매니저 활용 커넥션 관리
rawfishthelgh Oct 8, 2023
940e754
feat: 서비스 계층 추상화로 트랜잭션 적용 로직과 비즈니스 로직 분리
rawfishthelgh Oct 8, 2023
a208a88
refactor: checked 예외 변한처리 JdbcTemplate 담당
rawfishthelgh Oct 11, 2023
2c18f84
refactor: 불필요 오토커밋 해제처리 삭제
rawfishthelgh Oct 11, 2023
5d0eb39
refactor: DataSourceUtils에 동기화 처리 해제 역할 위임
rawfishthelgh Oct 11, 2023
ccdfaff
refactor: Dynamic Proxy 활용하여 동적으로 트랜잭션 처리
rawfishthelgh Oct 11, 2023
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48 changes: 35 additions & 13 deletions app/src/main/java/com/techcourse/dao/UserDao.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,10 +3,11 @@
import com.techcourse.domain.User;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import java.util.NoSuchElementException;

Expand All @@ -20,33 +21,54 @@ public UserDao(final JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}

public void insert(Connection con, final User user) {
public void insert(final User user) {
final var sql = "insert into users (account, password, email) values (?, ?, ?)";
jdbcTemplate.update(con,sql, user.getAccount(), user.getPassword(), user.getEmail());
try {
jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail());
} catch (SQLException e) {
throw new DataAccessException(e);
}
}

public void update(Connection con,final User user) {
public void update(final User user) {
String sql = "UPDATE users SET account = ?, password = ?, email = ? WHERE id = ?";
jdbcTemplate.update(con,sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
try {
jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
} catch (SQLException e) {
throw new DataAccessException(e) {
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실제 JdbcTemplate에서 SQLException을 잡은 후 자기네 DataAccessException으로 바꾸어 던지는 이유가 무엇일까요?

마드짱의 insert sql에 아무 글자나 넣어서 오타를 낸 후 실행해보면 JdbcSQLSyntaxErrorException이 나오는데,
image
예외의 패키지를 보면 org.h2.jdbc로 h2 라이브러리에서 제공하는 예외임을 알 수가 있죠.

이건 우리가 h2를 사용하기 때문에 h2 예외가 발생한 것이고, mysql을 쓰면 mysql 예외가, mariaDB를 쓰면 mariaDB 예외가 발생하겠죠.

지금의 UserDao는 catch문에서 SQLException 전체를 잡고 있는데.

    public void update(final User user) {
        String sql = "UPDATE users SET account = ?, password = ?, email = ? WHERE id = ?";
        try {
            jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
        } catch (SQLException e) {
            throw new DataAccessException(e) {
            };
        }
    }

만약 SyntaxError 하나만 잡아서 특별한 처리를 하는 상황이 왔다고 가정해 보아요.

    public void update(final User user) {
        String sql = "UPDATE users SET account = ?, password = ?, email = ? WHERE id = ?";
        try {
            jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
        } catch (JdbcSQLSyntaxErrorException e) {
            throw new DataAccessException(e) {
            };
        }
    }

h2를 쓰고 있는 지금은 syntax에러가 발생했을 때 catch문에서 딱 잡아주지만
만약 데이터베이스를 MySQL로 바꾸었다고 하면? 안 잡히겠죠! (두둥)
왜냐면 위 catch문에서 잡는 SyntaxError는 h2 예외이기 때문에
mysql에서 나온 SyntaxError는 당연히 안 잡겠죠?

이를 방지하려면 SQLException을 잡는 모든 try-catch문을 찾아가 h2 예외를 잡는 대신 mysql 예외를 잡도록 바꿔야겠네요.

public void update(final User user) {
        String sql = "UPDATE users SET account = ?, password = ?, email = ? WHERE id = ?";
        try {
            jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
        } catch (org.mysql.jdbc.JdbcSQLSyntaxErrorException e) {
            throw new DataAccessException(e) {
            };
        }
    }

그런데 운영 환경에서는 mysql을 쓰지만 테스트 환경에서는 h2를 쓰겠다! 라고 하면
또다시 모든 try-catch문을 찾아가 h2 예외를 잡는 catch문을 밑에 더 붙여줘야 할 거에요.

public void update(final User user) {
        String sql = "UPDATE users SET account = ?, password = ?, email = ? WHERE id = ?";
        try {
            jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
        } catch (org.mysql.jdbc.JdbcSQLSyntaxErrorException e) {
            throw new DataAccessException(e) {
            };
        } catch (org.h2.jdbc.JdbcSQLSyntaxErrorException e) {
            throw new DataAccessException(e) {
            };
        }
    }

'jdbcTemplate에서는 예외만 발생시키고 이걸 어떻게 처리할지는 dao에서 개발자가 결정하는게 옳다' 라고 하마드는 말씀해 주셨지만,
현재 사용중인 DBMS와 미래에 사용하게 될 DBMS의 종류까지 신경써가며 코드를 작성해야 하는 것이
과연 개발자에게 건강한 결정권을 주었다고 볼 수 있는지 모르겠어요.
하마드의 생각이 궁금하군요!

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오 여우의 상세한 리뷰를 보고 나니 제가 착각한 부분이 있었네요...!
JdbcTemplate이 SQL Exception을 던진다고 착각했는데, Checked 예외를 DataAccessException으로 바꿔 던지는 것을 간과하고 있었군요.
수정하도록 할게요 좋은 리뷰 고마워요ㅎㅎ

};
}

}

public List<User> findAll(Connection con) {
public List<User> findAll() {
String sql = "SELECT id, account, password, email FROM users";
return jdbcTemplate.query(con,sql, getUserRowMapper());
try {
return jdbcTemplate.query(sql, getUserRowMapper());
} catch (SQLException e) {
throw new DataAccessException(e);
}
}


public User findById(Connection con,final Long id) {
public User findById(final Long id) {
final var sql = "select id, account, password, email from users where id = ?";
return jdbcTemplate.queryForObject(con,sql, getUserRowMapper(), id)
.orElseThrow(() -> new NoSuchElementException("결과가 존재하지 않습니다"));
try {
return jdbcTemplate.queryForObject(sql, getUserRowMapper(), id)
.orElseThrow(() -> new NoSuchElementException("결과가 존재하지 않습니다"));
} catch (SQLException e) {
throw new DataAccessException(e);
}
}

public User findByAccount(Connection con,final String account) {
public User findByAccount(final String account) {
String sql = "SELECT id, account, password, email FROM users WHERE account = ?";
return jdbcTemplate.queryForObject(con,sql, getUserRowMapper(), account)
.orElseThrow(() -> new NoSuchElementException("결과가 존재하지 않습니다"));
try {
return jdbcTemplate.queryForObject(sql, getUserRowMapper(), account)
.orElseThrow(() -> new NoSuchElementException("결과가 존재하지 않습니다"));
} catch (SQLException e) {
throw new DataAccessException(e);
}
}

private RowMapper<User> getUserRowMapper() {
Expand Down
25 changes: 15 additions & 10 deletions app/src/main/java/com/techcourse/dao/UserHistoryDao.java
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Expand Up @@ -3,9 +3,10 @@
import com.techcourse.domain.UserHistory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;

import java.sql.Connection;
import java.sql.SQLException;

public class UserHistoryDao {

Expand All @@ -17,15 +18,19 @@ public UserHistoryDao(final JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}

public void log(Connection con, 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.update(con, sql,
userHistory.getUserId(),
userHistory.getAccount(),
userHistory.getPassword(),
userHistory.getEmail(),
userHistory.getCreatedAt(),
userHistory.getCreateBy()
);
try {
jdbcTemplate.update(sql,
userHistory.getUserId(),
userHistory.getAccount(),
userHistory.getPassword(),
userHistory.getEmail(),
userHistory.getCreatedAt(),
userHistory.getCreateBy()
);
} catch (SQLException e) {
throw new DataAccessException(e);
}
}
}
79 changes: 79 additions & 0 deletions app/src/main/java/com/techcourse/service/TxUserService.java
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@@ -0,0 +1,79 @@
package com.techcourse.service;

import com.techcourse.domain.User;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.datasource.DataSourceUtils;
import org.springframework.transaction.support.TransactionSynchronizationManager;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

public class TxUserService implements UserService {

private final UserService userService;
private final DataSource dataSource;

public TxUserService(UserService userService, DataSource dataSource) {
this.userService = userService;
this.dataSource = dataSource;
}

public User findById(final long id) {
Connection connection = DataSourceUtils.getConnection(dataSource);
TransactionSynchronizationManager.bindResource(dataSource, connection);
try {
connection.setAutoCommit(false);
User user = userService.findById(id);
connection.commit();
return user;
} catch (Exception e) {
rollback(connection);
throw new DataAccessException(e);
} finally {
DataSourceUtils.releaseConnection(connection, dataSource);
TransactionSynchronizationManager.unbindResource(dataSource);
}
}


public void insert(final User user) {
Connection connection = DataSourceUtils.getConnection(dataSource);
TransactionSynchronizationManager.bindResource(dataSource, connection);
try {
connection.setAutoCommit(false);
userService.insert(user);
connection.commit();
} catch (Exception e) {
rollback(connection);
throw new DataAccessException(e);
} finally {
DataSourceUtils.releaseConnection(connection, dataSource);
TransactionSynchronizationManager.unbindResource(dataSource);
}
}

public void changePassword(final long id, final String newPassword, final String createBy) {
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트랜잭션이 적용된 서비스와 안 적용된 서비스 이렇게 두 개를 만드신 건가요? 😮

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순수 비즈니스 로직만 가진 서비스 클래스 (AppUserService
)와, 트랜잭션 처리 관심사를 담당하면서 위 AppUserService를 인스턴스로 받아 비즈니스 로직을 호출하는 클래스로 구분해서 둘의 관심사를 끊어내기 위함이었습니다.(요구사항을 지키기 위해서요)

그런데 테스트 코드에서

AppUserService appUserService = new AppUserService(userDao, userHistoryDao);
final var userService = new TxUserService(appUserService,dataSource);

다음과 같이 직접 구현체를 주입시켜야 하는 어색함이 있네요...

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오홍 이해했습니다!
테스트 코드에서는 테스트하려는 구현체를 직접 넣는 경우가 흔하기 때문에 저는 어색하다고 느껴지지 않았어요 😊

Connection connection = DataSourceUtils.getConnection(dataSource);
TransactionSynchronizationManager.bindResource(dataSource, connection);
try {
connection.setAutoCommit(false);
userService.changePassword(id, newPassword, createBy);
connection.commit();
} catch (Exception e) {
rollback(connection);
throw new DataAccessException(e);
} finally {
DataSourceUtils.releaseConnection(connection, dataSource);
TransactionSynchronizationManager.unbindResource(dataSource);
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releaseConnection() 메서드 안에 unbindResource() 작업을 포함해도 되지 않을까라는 생각이 들어요!

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좋은 생각입니다 👍

}
}

private void rollback(Connection connection) {
try {
connection.rollback();
} catch (SQLException ex) {
throw new DataAccessException(ex);
}
}
}
50 changes: 16 additions & 34 deletions app/src/test/java/com/techcourse/dao/UserDaoTest.java
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Expand Up @@ -3,14 +3,11 @@
import com.techcourse.config.DataSourceConfig;
import com.techcourse.domain.User;
import com.techcourse.support.jdbc.init.DatabasePopulatorUtils;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

import java.sql.Connection;
import java.sql.SQLException;

import static org.assertj.core.api.Assertions.assertThat;
Expand All @@ -19,77 +16,62 @@ class UserDaoTest {

private UserDao userDao;
private DataSource dataSource;
private Connection con;

@BeforeEach
void setup() throws SQLException {
void setup() {
DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
dataSource = DataSourceConfig.getInstance();
con = dataSource.getConnection();
userDao = new UserDao(new JdbcTemplate());
userDao = new UserDao(new JdbcTemplate(dataSource));
final var user = new User("gugu", "password", "[email protected]");
userDao.insert(con, user);
}

@AfterEach
void close() throws SQLException {
con.close();
userDao.insert(user);
}

@Test
void findAll() throws SQLException {
Connection con = dataSource.getConnection();
final var users = userDao.findAll(con);
void findAll() {
final var users = userDao.findAll();

assertThat(users).isNotEmpty();
}

@Test
void findById() throws SQLException {
Connection con = dataSource.getConnection();
void findById() {

final var user = userDao.findById(con, 1L);
final var user = userDao.findById(1L);

assertThat(user.getAccount()).isEqualTo("gugu");
}

@Test
void findByAccount() throws SQLException {
Connection con = dataSource.getConnection();
void findByAccount() {

final var account = "gugu";
final var user = userDao.findByAccount(con, account);
final var user = userDao.findByAccount(account);

assertThat(user.getAccount()).isEqualTo(account);
}

@Test
void insert() throws SQLException {
Connection con1 = dataSource.getConnection();
Connection con2 = dataSource.getConnection();
void insert() {

final var account = "insert-gugu";
final var user = new User(account, "password", "[email protected]");
userDao.insert(con1, user);
userDao.insert(user);

final var actual = userDao.findById(con2, 2L);
final var actual = userDao.findById(2L);

assertThat(actual.getAccount()).isEqualTo(account);
}

@Test
void update() throws SQLException {
Connection con1 = dataSource.getConnection();
Connection con2 = dataSource.getConnection();
Connection con3 = dataSource.getConnection();
void update() {

final var newPassword = "password99";
final var user = userDao.findById(con1, 1L);
final var user = userDao.findById(1L);
user.changePassword(newPassword);

userDao.update(con2, user);
userDao.update(user);

final var actual = userDao.findById(con3, 1L);
final var actual = userDao.findById(1L);

assertThat(actual.getPassword()).isEqualTo(newPassword);
}
Expand Down
6 changes: 2 additions & 4 deletions app/src/test/java/com/techcourse/service/MockUserHistoryDao.java
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Expand Up @@ -5,17 +5,15 @@
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(Connection con, UserHistory userHistory) {
super.log(con, userHistory);
public void log(UserHistory userHistory) {
super.log(userHistory);
throw new DataAccessException();
}
}
9 changes: 3 additions & 6 deletions app/src/test/java/com/techcourse/service/UserServiceTest.java
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Expand Up @@ -11,7 +11,6 @@
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

import static org.assertj.core.api.Assertions.assertThat;
Expand All @@ -23,17 +22,15 @@ class UserServiceTest {
private JdbcTemplate jdbcTemplate;
private UserDao userDao;
private DataSource dataSource;
private Connection con;

@BeforeEach
void setUp() throws SQLException {
this.jdbcTemplate = new JdbcTemplate();
this.userDao = new UserDao(jdbcTemplate);
DatabasePopulatorUtils.execute(DataSourceConfig.getInstance());
dataSource = DataSourceConfig.getInstance();
con = dataSource.getConnection();
this.jdbcTemplate = new JdbcTemplate(dataSource);
this.userDao = new UserDao(jdbcTemplate);
final var user = new User("gugu", "password", "[email protected]");
userDao.insert(con, user);
userDao.insert(user);
}

@Test
Expand Down
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