DTO란?

    • DTO란 Data Transfer Object의 약자
    • 계층간 데이터 교환을 위한 자바빈즈
    • 여기서의 계층이란 컨트롤러 뷰, 비지니스 계층, 퍼시스턴스 계층을 의미
    • 일반적으로 DTO는 로직을 가지고 있지 않고, 순수한 데이터 객체
    • 필드와 getter, setter를 가진다. 추가적으로 toString(), equals(), hashCode()등의 Object 메소드를 오버라이딩 할 수 있다.

    DTO의 예

    public class ActorDTO {
        private Long id;
        private String firstName;
        private String lastName;
        public String getFirstName() {
            return this.firstName;
        }
        public String getLastName() {
            return this.lastName;
        }
        public Long getId() {
            return this.id;
        }
        // ......
    }

    DAO란?

    • DAO란 Data Access Object의 약자로 데이터를 조회하거나 조작하는 기능을 전담하도록 만든 객체이다.
    • 보통 데이터베이스를 조작하는 기능을 전담하는 목적으로 만들어진다.

     

    ConnectionPool 이란?

    • DB연결은 비용이 많이 들게 된다.
    • 커넥션 풀은 미리 커넥션을 여러 개 맺어 둔다..
    • 커넥션이 필요하면 커넥션 풀에게 빌려서 사용한 후 반납한다.
    • 커넥션을 반납하지 않으면 어떻게 될까?

     

    DataSource란?

    • DataSource는 커넥션 풀을 관리하는 목적으로 사용되는 객체이다.
    • DataSource를 이용해 커넥션을 얻어오고 반납하는 등의 작업을 수행한다.

    Spring JDBC를 이용한 DAO작성 실습

     

    실습코드

     

    pom.xml

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    
    	<groupId>kr.or.connect</groupId>
    	<artifactId>daoexam</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>daoexam</name>
    	<url>http://maven.apache.org</url>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<spring.version>4.3.5.RELEASE</spring.version>
    	</properties>
    
    	<dependencies>
    		<!-- Spring -->
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-context</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-jdbc</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-tx</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    
    		<!-- basic data source -->
    		<dependency>
    			<groupId>org.apache.commons</groupId>
    			<artifactId>commons-dbcp2</artifactId>
    			<version>2.1.1</version>
    		</dependency>
    
    
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>5.1.45</version>
    		</dependency>
    
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>3.8.1</version>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.apache.maven.plugins</groupId>
    				<artifactId>maven-compiler-plugin</artifactId>
    				<version>3.6.1</version>
    				<configuration>
    					<source>1.8</source>
    					<target>1.8</target>
    				</configuration>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

     

    패키지 생성 위치 확인

     

    ApplicationConfig.java

    package kr.or.connect.daoexam.config;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.Import;
    
    @Configuration
    @Import({DBConfig.class})
    public class ApplicationConfig {
    
    }

    DBConfig.java

    package kr.or.connect.daoexam.config;
    
    import javax.sql.DataSource;
    
    import org.apache.commons.dbcp2.BasicDataSource;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.transaction.annotation.EnableTransactionManagement;
    
    @Configuration
    @EnableTransactionManagement
    public class DBConfig {
    	private String driverClassName = "com.mysql.jdbc.Driver";
        private String url = "jdbc:mysql://localhost:3306/connectdb?useUnicode=true&characterEncoding=utf8";
    
        private String username = "connectuser";
        private String password = "connect123!@#";
    
        @Bean
        public DataSource dataSource() {
        	BasicDataSource dataSource = new BasicDataSource();
            dataSource.setDriverClassName(driverClassName);
            dataSource.setUrl(url);
            dataSource.setUsername(username);
            dataSource.setPassword(password);
            return dataSource;
    
        }
    }

    DataSourceTest.java

    package kr.or.connect.daoexam.main;
    
    import java.sql.Connection;
    
    import javax.sql.DataSource;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    import kr.or.connect.daoexam.config.ApplicationConfig;
    
    public class DataSourceTest {
    
    	public static void main(String[] args) {
    		ApplicationContext ac = new AnnotationConfigApplicationContext(ApplicationConfig.class);
    		DataSource ds = ac.getBean(DataSource.class);
    		Connection conn = null;
    		try {
    			conn = ds.getConnection();
    			if(conn != null)
    				System.out.println("접속 성공^^");
    		}catch (Exception e) {
    			e.printStackTrace();
    		}finally {
    			if(conn != null) {
    				try {
    					conn.close();
    				}catch (Exception e) {
    					e.printStackTrace();
    				}
    			}
    		}
    	}
    
    }

    접속하는 과정 여기까지

    -----------------------------------------------------------------------------------------------------------------------------------

     

    Spring JDBC 실습 과정 

    select 부분 작성하기

     

     

    Role.java         DTO작성 

    package kr.or.connect.daoexam.dto;
    
    public class Role {
    	private int roleId;
    	private String description;
    	
    	public int getRoleId() {
    		return roleId;
    	}
    	public void setRoleId(int roleId) {
    		this.roleId = roleId;
    	}
    	public String getDescription() {
    		return description;
    	}
    	public void setDescription(String description) {
    		this.description = description;
    	}
    	@Override
    	public String toString() {
    		return "Role [roleId=" + roleId + ", description=" + description + "]";
    	}
    	
    }
     

    toString 객체가 가지고 있는 값을 문자열로 한번에 편하게 보기위해서 만들어준다.

    실제 값들이 다 들어있는지 확인하기에 편하다.

     

    RoleDaoSqls.java          쿼리문 가지고 있는 객체 만들기 -> 데이터 엑세스(DAO) (만드는 순서

    package kr.or.connect.daoexam.dao;
    
    public class RoleDaoSqls {
    	public static final String SELECT_ALL = "SELECT role_id, description FROM role order by role_id";
    }

    상수는 대문자사용 구별은 _ 사용

     

    RoleDao.java

    package kr.or.connect.daoexam.dao;
    
    import static kr.or.connect.daoexam.dao.RoleDaoSqls.*;
    
    import java.util.Collections;
    import java.util.List;
    
    import javax.sql.DataSource;
    
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.RowMapper;
    import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
    import org.springframework.stereotype.Repository;
    
    import kr.or.connect.daoexam.dto.Role;
    @Repository
    public class RoleDao {
    	private NamedParameterJdbcTemplate jdbc;
    	private RowMapper<Role> rowMapper = BeanPropertyRowMapper.newInstance(Role.class);
    
    	public RoleDao(DataSource dataSource) {
    		this.jdbc = new NamedParameterJdbcTemplate(dataSource);
    	}
    	
    	public List<Role> selectAll(){
    		return jdbc.query(SELECT_ALL, Collections.emptyMap(), rowMapper);
    	}
    
    }
    

    ApplicationConfig.java 에 추가

    @ComponentScan(basePackages = { "kr.or.connect.daoexam.dao" })

    RoleDao.java 에 @Repository가 붙어있는 클래스를 Bean으로 등록해준것과 같은 역할을 해준다.

     

     

    SelectAllTest.java

    package kr.or.connect.daoexam.main;
    
    import java.util.List;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    import kr.or.connect.daoexam.config.ApplicationConfig;
    import kr.or.connect.daoexam.dao.RoleDao;
    import kr.or.connect.daoexam.dto.Role;
    
    public class SelectAllTest {
    
    	public static void main(String[] args) {
    		ApplicationContext ac = new AnnotationConfigApplicationContext(ApplicationConfig.class); 
    		
    		RoleDao roleDao =ac.getBean(RoleDao.class);
    
    		List<Role> list = roleDao.selectAll();
    		
    		for(Role role: list) {
    			System.out.println(role);
    		}
    
    	}
    
    }

    ---------------------------------------------------------------------------------------

    실습코드 

    Spring JDBC 실습 과정 

    insert, update 부분 작성하기

     

    RoleDaoSqls.java에 추가 

    public static final String UPDATE = "UPDATE role SET description = :description WHERE ROLE_ID = :roleId";
    

    :description :roleId<< 값으로 바인딩 될 부분

     

    RoleDao.java

    package kr.or.connect.daoexam.dao;
    
    import static kr.or.connect.daoexam.dao.RoleDaoSqls.*;
    
    import java.util.Collections;
    import java.util.List;
    import java.util.Map;
    
    import javax.sql.DataSource;
    
    import org.springframework.dao.EmptyResultDataAccessException;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.RowMapper;
    import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
    import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
    import org.springframework.jdbc.core.namedparam.SqlParameterSource;
    import org.springframework.jdbc.core.simple.SimpleJdbcInsert;
    import org.springframework.stereotype.Repository;
    
    import kr.or.connect.daoexam.dto.Role;
    @Repository
    public class RoleDao {
    	private NamedParameterJdbcTemplate jdbc;
    	private SimpleJdbcInsert insertAction;
    	private RowMapper<Role> rowMapper = BeanPropertyRowMapper.newInstance(Role.class);
    
    	public RoleDao(DataSource dataSource) {
    		this.jdbc = new NamedParameterJdbcTemplate(dataSource);
    		this.insertAction = new SimpleJdbcInsert(dataSource)
                    .withTableName("role");
    
    	}
    	
    	public int insert(Role role) {
    		SqlParameterSource params = new BeanPropertySqlParameterSource(role);
    		return insertAction.execute(params);
    	}
    
    	public int update(Role role) {
    		SqlParameterSource params = new BeanPropertySqlParameterSource(role);
    		return jdbc.update(UPDATE, params);
    	}
    	
    
    }

    JDBCTest.java

    package kr.or.connect.daoexam.main;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    import kr.or.connect.daoexam.config.ApplicationConfig;
    import kr.or.connect.daoexam.dao.RoleDao;
    import kr.or.connect.daoexam.dto.Role;
    
    public class JDBCTest {
    
    	public static void main(String[] args) {
    		ApplicationContext ac = new AnnotationConfigApplicationContext(ApplicationConfig.class);
    
    		RoleDao roleDao = ac.getBean(RoleDao.class);
    		
    		Role role = new Role();
    		role.setRoleId(201);
    		role.setDescription("PROGRAMMER");
    		
    		int count = roleDao.insert(role);
    		System.out.println(count + "건 입력하였습니다.");
    			
    		int count = roleDao.update(role);
    		System.out.println(count +  " 건 수정하였습니다.");
    	}
    
    }

    -----------------------------------------------------------------------------------------------------------------------------------

    Spring JDBC 실습 과정 

    select, delete 부분 작성하기

     

    RoleDaoSqls.java에 추가

    public static final String SELECT_BY_ROLE_ID = "SELECT role_id, description FROM role where role_id = :roleId";
    public static final String DELETE_BY_ROLE_ID = "DELETE FROM role WHERE role_id = :roleId";

    RoleDao.java에 추가

    package kr.or.connect.daoexam.dao;
    
    import static kr.or.connect.daoexam.dao.RoleDaoSqls.*;
    
    import java.util.Collections;
    import java.util.List;
    import java.util.Map;
    
    import javax.sql.DataSource;
    
    import org.springframework.dao.EmptyResultDataAccessException;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.RowMapper;
    import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
    import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
    import org.springframework.jdbc.core.namedparam.SqlParameterSource;
    import org.springframework.jdbc.core.simple.SimpleJdbcInsert;
    import org.springframework.stereotype.Repository;
    
    import kr.or.connect.daoexam.dto.Role;
    @Repository
    public class RoleDao {
    	private NamedParameterJdbcTemplate jdbc;
    	private SimpleJdbcInsert insertAction;
    	private RowMapper<Role> rowMapper = BeanPropertyRowMapper.newInstance(Role.class);
    
    	public RoleDao(DataSource dataSource) {
    		this.jdbc = new NamedParameterJdbcTemplate(dataSource);
    		this.insertAction = new SimpleJdbcInsert(dataSource)
                    .withTableName("role");
    	}
    	
    	public int deleteById(Integer id) {
    		Map<String, ?> params = Collections.singletonMap("roleId", id);
    		return jdbc.update(DELETE_BY_ROLE_ID, params);
    	}
    	
    	public Role selectById(Integer id) {
    		try {
    			Map<String, ?> params = Collections.singletonMap("roleId", id);
    			return jdbc.queryForObject(SELECT_BY_ROLE_ID, params, rowMapper);		
    		}catch(EmptyResultDataAccessException e) {
    			return null;
    		}
    	}
    
    }

    JDBCTest.java에 추가

    Role resultRole = roleDao.selectById(201);
    System.out.println(resultRole);
    		
    int deleteCount = roleDao.deleteById(500);
    System.out.println(deleteCount + "건 삭제하였습니다.");
    	
    Role resultRole2 = roleDao.selectById(500);
    System.out.println(resultRole2);
    		

     

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