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Java를 위한 프레임 워크 mybatis

조용한여우 2021. 8. 2. 16:41

Java를 위한 프레임워크

            * 프레임워크 - 짜여진 틀

                    틀에 대한 문법

                                - 편리

                                - 자유

            * MyBatis(iBatis)

                http://blog.mybatis.org 

 

The MyBatis Blog

A blog about the the MyBatis data mapper framework.

blog.mybatis.org

 

            SQL을 효율적으로 사용하기 위한 프레임워크

                → sql mapper

            1. 라이브러리 ( Library )

            2. 환경설정

                    1. log 출력용

                            log4j

                    2. Mybatis 환경

                    3. sql mapper 파일

// log4j.xml
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
     <appender name="console" class="org.apache.log4j.ConsoleAppender">
          <layout class="org.apache.log4j.PatternLayout">
               <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} [%-5p](%-35c{1}:%-3L) %m%n" />
          </layout>
     </appender>
     <root>
     	<level value="DEBUG" />
     	<appender-ref ref="console"/>
     </root>
</log4j:configuration>

 

// myBatisConfig.xml
<?xml version= "1.0" encoding ="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<environments default="mariadb1">
		<environment id="mariadb1">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
				<property name="driver" value="org.mariadb.jdbc.Driver" />
				<property name="url" value="jdbc:mariadb://localhost:3306/sample" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
		
		<environment id="mariadb2">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
				<property name="driver" value="org.mariadb.jdbc.Driver" />
				<property name="url" value="jdbc:mariadb://localhost:3306/project" />
				<property name="username" value="project" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
</configuration>

 

// MyBatisEx01.java

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.ibatis.session.TransactionIsolationLevel;

public class MyBatisEx01 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( is != null ) 
				try { is.close(); } catch( IOException e ) {}
		}
	}

}

 

<!-- mapper.xml -->
<mapper namespace="mybatis" >
	<select id="select1" resultType="DeptTO" >
		select deptno, dname, loc
		from dept
		where deptno=10;
	</select>
</mapper>

 

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisEx03 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		SqlSession sqlSession = null;
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
			
			sqlSession = sqlSessionFactory.openSession();
			System.out.println( "데이터베이스와 연결됨" );
			
			DeptTO to = (DeptTO)sqlSession.selectOne( "select1" );
			
			System.out.println( to.getDeptno() );
			System.out.println( to.getDname() );
			System.out.println( to.getLoc() );
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( sqlSession != null ) sqlSession.close();
			if ( is != null ) try { is.close(); } catch( IOException e ) {}
			
		}
	}

}

 

selectOne은 결과가 하나만 실행 (여러개면 에러)

결과 데이터가 없으면 NullPointException 에러뜸

 

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import java.util.Set;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisEx04 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		SqlSession sqlSession = null;
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
			
			sqlSession = sqlSessionFactory.openSession();
			System.out.println( "데이터베이스와 연결됨" );
			
			Map map = sqlSession.selectOne( "select5" );
			Set<String> keys = map.keySet();
			for( String key : keys) {
				// 컬럼명
				// System.out.println( key );
				
				System.out.println( map.get( key ) );
				
			}
			
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( sqlSession != null ) sqlSession.close();
			if ( is != null ) try { is.close(); } catch( IOException e ) {}
			
		}
	}

}


key만 출력하면 컬럼명만 출력됨

map.get(key); 출력하면 데이터가 출력됨

 

프로젝트를 새로 생성하여 문제풀기

        사원명의 앞자리 일부만 입력하여 사원정보를 출력하는 mybatis 구문 완성

            (empno, ename, sal, deptno)

/* EmpTO.java */
public class EmpTO {
	private String empno;
	private String ename;
	private String sal;
	private String deptno;
	
	public String getEmpno() {
		return empno;
	}
	public void setEmpno(String empno) {
		this.empno = empno;
	}
	public String getEname() {
		return ename;
	}
	public void setEname(String ename) {
		this.ename = ename;
	}
	public String getSal() {
		return sal;
	}
	public void setSal(String sal) {
		this.sal = sal;
	}
	public String getDeptno() {
		return deptno;
	}
	public void setDeptno(String deptno) {
		this.deptno = deptno;
	}
}

getter / setter 생성해줌

 

<!-- log4j.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/doc-files/log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
     <appender name="console" class="org.apache.log4j.ConsoleAppender">
          <layout class="org.apache.log4j.PatternLayout">
               <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} [%-5p](%-35c{1}:%-3L) %m%n" />
          </layout>
     </appender>
     <root>
     	<level value="DEBUG" />
     	<appender-ref ref="console"/>
     </root>
</log4j:configuration>

console에 보여줌

 

<!-- myBatisConfig.xml -->
<?xml version= "1.0" encoding ="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<environments default="mariadb1">
		<environment id="mariadb1">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
				<property name="driver" value="org.mariadb.jdbc.Driver" />
				<property name="url" value="jdbc:mariadb://localhost:3306/sample" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
		
		<environment id="mariadb2">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
				<property name="driver" value="org.mariadb.jdbc.Driver" />
				<property name="url" value="jdbc:mariadb://localhost:3306/project" />
				<property name="username" value="project" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<mapper resource="mapper.xml"/>
	</mappers>
</configuration>

한가지만 사용할건데 나중을 위해 두가지 선언

 

<!-- mapper.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- mapper.xml -->
<mapper namespace="mybatis" >	
	<select id="selectList" parameterType="String" resultType="EmpTO" >
		select empno, ename, sal, deptno
		from emp
		where ename like concat( #{ename}, '%' );
	</select>
</mapper>

데이터 조회할 sql문을 작성

 

/* MyBatisEx01.java */
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisEx01 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		SqlSession sqlSession = null;
		
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
			
			sqlSession = sqlSessionFactory.openSession();
			System.out.println( "데이터베이스와 연결됨" );

			List<EmpTO> lists = sqlSession.selectList( "selectList", "S" );
			
			System.out.println( lists.size() + "개 검색" );
			
			for(EmpTO to : lists ) {
				System.out.print( to.getEmpno() + " " );
				System.out.print( to.getEname() + " " );
				System.out.print( to.getSal() + " " );
				System.out.println( to.getDeptno() );
			}
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( sqlSession != null ) sqlSession.close();
			if ( is != null ) try { is.close(); } catch( IOException e ) {}
			
		}
	}

}

 

MyBatis 테이블 만들기

<!-- mapper.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- mapper2.xml -->
<mapper namespace="mybatis3" >	
	<update id="createtable1" parameterType="String">
		${ value }
	</update>
</mapper>

//MyBatisEx10.java
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
public class MyBatisEx12 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		SqlSession sqlSession = null;
		
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
			
			sqlSession = sqlSessionFactory.openSession(true);
			System.out.println( "데이터베이스와 연결됨" );
			
			String sql = "create table tbl1 (col1 varchar(10) )";
			int result = sqlSession.update( "createtable1", sql );
			
			System.out.println( "성공 : " + result );
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( sqlSession != null ) sqlSession.close();
			if ( is != null ) try { is.close(); } catch( IOException e ) {}
			
		}
	}

}

 

비슷한 방법으로 만드는법

<!-- mapper.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- mapper2.xml -->
<mapper namespace="mybatis3" >	
	<update id="createtable1" parameterType="String">
		${ value }
	</update>
	
	<update id="createtable2" parameterType="String">
		create table ${ value }
		( col varchar(10) )
	</update>
</mapper>

// MyBatisEx01.java
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
public class MyBatisEx12 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String resource = "myBatisConfig.xml";
		
		InputStream is = null;
		SqlSession sqlSession = null;
		
		
		try {
			is = Resources.getResourceAsStream(resource);
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
			System.out.println( "설정이 성공적으로 호출됨" );
			
			sqlSession = sqlSessionFactory.openSession(true);
			System.out.println( "데이터베이스와 연결됨" );
			
			// String sql = "create table tbl1 (col1 varchar(10) )";
			// int result = sqlSession.update( "createtable1", sql );
			int result = sqlSession.update( "createtable2", "tbl2" );
			
			System.out.println( "성공 : " + result );
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.out.println( "[에러] : " + e.getMessage() );
		} finally {
			if ( sqlSession != null ) sqlSession.close();
			if ( is != null ) try { is.close(); } catch( IOException e ) {}
			
		}
	}

}

 

            * Spring(MVC Model2) - 모델2를 쉽게 개발하려 제공하는 프레임워크

 

 

 

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