Mybatis①

1. 프로젝트 생성

 

 

2. 기본 설정

1) Spring Config

package com.oracle.oBootMybatis01.configration;

import javax.persistence.EntityManager;
import javax.sql.DataSource;

import org.springframework.context.annotation.Configuration;

@Configuration
public class SpringConfig {
	
	private EntityManager 	em;
	private DataSource 		dataSource;
	
	public SpringConfig(EntityManager em, DataSource dataSource) {
		this.em = em;
		this.dataSource = dataSource;
	}

}

[오류1] 

Parameter 1 of constructor in com.oracle.oBootMybatis01.configration.SpringConfig required a bean of type 'javax.activation.DataSource' that could not be found.

 

-> import javax.activation.DataSource; 이 아니라 import javax.sql.DataSource;를 임포트 해야함.

 

 

2) application.yml

server: 
  port: 8386
# Oracle Connect
spring:
  datasource:
    driver-class-name: oracle.jdbc.driver.OracleDriver
    url: jdbc:oracle:thin:@localhost:1521/xe
    username: scott
    password: tiger
#ORM JPA
  jpa:
    hibernate:
      ddl-auto: none
    properties:
     hibernate:
      show_sql: true
      format_sql: true
   
#view resolver(Templete -> jsp use)
  mvc:
    view:
      prefix: /WEB-INF/views/
      suffix: .jsp
      
#Mybatis
mybatis:
  # dto Location
  # type-aliases-package: com.oracle.oBootMybatis01.model
  # xml Location
  config-location: classpath:configuration.xml
  mapper-locations: classpath:mappers/*.xml

* config-location: classpath:configuration.xml

* mapper-location: classpath:mappers/*.xml -> mappers 폴더 안에 있는 모든 파일들 

[에러2]  Failed to configure a DataSource   

-> Database에 연결할 때 필요한 정보가 없기 때문에, 어플리케이션 실행에 실패했다.

application.properties 혹은 appliction.yml 파일 확인하기

-> Mybatis01-> MyBatis01로 되어 있음

 

 

 

4. 게시판 리스트 불러오기

1) controller

package com.oracle.oBootMybatis01.controller;

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.oracle.oBootMybatis01.model.Emp;
import com.oracle.oBootMybatis01.service.EmpService;
import com.oracle.oBootMybatis01.service.Paging;

@Controller
public class EmpController {

	private static final Logger logger = LoggerFactory.getLogger(EmpController.class);
	
	@Autowired
	private EmpService es;
	
	@RequestMapping(value = "list")
	public String list(Emp emp, String currentPage, Model model) {
		logger.info("컨트롤러 list 시작");
		int total = es.total();
		
		System.out.println("컨트롤러 list total : " + total);
		Paging pg = new Paging(total, currentPage);
		emp.setStart(pg.getStart());
		emp.setEnd(pg.getEnd());
		List<Emp> listEmp = es.listEmp(emp);
		System.out.println("Emp 컨트롤러 list listEmp.size() : " + listEmp.size());
		model.addAttribute("listEmp", listEmp);
		model.addAttribute("pg", pg);
		model.addAttribute("total", total);
		return "list";
	}
}

2) 게시글 총 갯수 구하기 

- es.total();   

@Service
public class EmpServiceImpl implements EmpService {

	@Autowired
	private EmpDao ed;
	
	@Override
	public int total() {
		System.out.println("Emp total 서비스 시작");
		int totCnt = ed.total();
		return totCnt;
	}
}

 3) ed.total();

@Repository
public class EmpDaoImpl implements EmpDao {

	@Autowired
	private SqlSession 	session;
	
	@Override
	public int total() {
		int totCnt = 0;
		System.out.println("EmpDao total 시작");
		try {
			totCnt = session.selectOne("mjTotalEmp");
			System.out.println("EmpDao totCnt : " + totCnt);
		} catch (Exception e) {
			System.out.println("EmpDao Error : " + e.getMessage());
		}
		return totCnt;
	}
}

4) totCnt = session.selectOne("mjTotalEmp");

<?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 namespace="com.oracle.oBootMybatis01.EmpMapper">
	<select id="mjTotalEmp" resultType="int">
		select count(*) from emp
	</select>
</mapper>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
	<typeAliases>
		<typeAlias alias="Emp" type="com.oracle.oBootMybatis01.model.Emp"/>
	</typeAliases>
</configuration>

** SqlSession

: mapper.xml 에 등록된 sql 문을 실행하고 트랜잭션을 관리

selectOne	select 문이 실행된 하나의 객체를 리턴한다.
selectList	select 문이 실행되어 여러개의  객체가 담긴 리스트를 리턴
selectMap	결과 목록이 Map으로 변환되어 리턴
insert	insert 문이 실행
update	update 문이 실행
delete	delete 문이 실행

 

package com.oracle.oBootMybatis01.service;

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class Paging {
	private int currentPage = 1;
    private int rowPage  = 10;
    private int pageBlock = 10;
    private int start;
    private int end;
    private int startPage;
    private int endPage;
    private int total;
    private int totalPage;
	
	public Paging(int total, String currentPage1) {
		//예) total = 123  currentPage = 2 
		this.total = total;
		if(currentPage1 != null) {
			this.currentPage = Integer.parseInt(currentPage1);
		}
		start = (currentPage - 1) * rowPage + 1;	 //1* 10 + 1 = 11
		end   =  start + rowPage - 1;				 //11+10 + 1 = 20
		totalPage = (int)Math.ceil((double)total/rowPage); //  123/10 = 13
		startPage = currentPage - (currentPage - 1 ) % pageBlock;  
		endPage = startPage + pageBlock - 1;
		if(endPage > totalPage ) {
			endPage = totalPage;
		}
	}
}

@Override
	public List<Emp> listEmp(Emp emp) {
		List<Emp> empList = null;
		System.out.println("Emp listEmp 서비스 시작");
		empList = ed.listEmp(emp);
		System.out.println("Emp listEmp 서비스 empList.size() : " + empList.size());
		return empList;
	}

@Override
	public List<Emp> listEmp(Emp emp) {
		List<Emp> empList = null;
		
		try {
			empList = session.selectList("mjEmpListAll3", emp);
		} catch (Exception e) {
			System.out.println("EmpDaoImpl listEmp Exception : " + e.getMessage());
		}
		return empList;
	}

* parameter는 #{}으로 사용

<select id="mjEmpListAll" parameterType="Emp" resultType="Emp">
		SELECT *
		FROM   (
				SELECT rownum rn, a.*
				FROM (SELECT * FROM emp ORDER BY empno) a
				)
		WHERE rn BETWEEN #{start} AND #{end}
</select>

[오류3] Whitelabel Error Page

-> Spring Boot에서 내장된 Tomcat을 사용하는 경우 jsp를 처리하는 서블릿을 추가하지 않아 발생하는 것으로 pom.xml에 아래와 같이 추가해준다

<dependency> 
			<groupId>javax.servlet</groupId> 
			<artifactId>jstl</artifactId> 
		</dependency> 
		<dependency> 
			<groupId>org.apache.tomcat.embed</groupId> 
			<artifactId>tomcat-embed-jasper</artifactId> 
</dependency>

 

* Mybatis의 기본 구조를 이해해보자 * 

controller -> sevice -> dao -> session에 mapping 된 sql 문 실행