[MYBATIS] Mybatis DB연결하기

📌 Main.java 생성

package main;

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 mapper.StudentMapper;

public class Main1 {
	private static SqlSessionFactory sqlMap;
	static { //static 초기화 블럭 : 클래스 변수 초기화 담당
		//바이트형 입력 스트림. 
		InputStream input = null;
		try {
//input : mybatis-config.xml의 내용 저장
			input = Resources.getResourceAsStream("mapper/mybatis-config.xml");
		} catch(IOException e) {
			e.printStackTrace();
		}
//sqlMap : Mybatis 설정 객체
//mybatis-config.xml 파일을 읽어, 결과들을 sqlMap 변수 저장
//1. db와 연결 완료
//2. sql 구문들을 저장
		sqlMap = new SqlSessionFactoryBuilder().build(input);
	}
	private static Class<StudentMapper> cls = StudentMapper.class;
	
	public static void main(String[] args) {
		//session : sqlMap객체에 저장된 db로 접속.
		SqlSession session = sqlMap.openSession();
		System.out.println("모든 학생 정보 조회하기");
		List<Student> list = session.getMapper(cls).select();
		for(Student s : list) System.out.println(s);
		System.out.println("1학년 학생 정보 조회하기");
		list = session.getMapper(cls).select_grade(1);
		for(Student s : list) System.out.println(s);
		System.out.println("2학년 학생 정보 조회하기");
		list = session.getMapper(cls).select_grade(2);
		for(Student s : list) System.out.println(s);
    System.out.println("학번으로 학생 정보 조회하기");
		list = session.getMapper(cls).select_studno("9711");
		for(Student s : list) System.out.println(s);
		System.out.println("이름에 김자가 들어가는 학생 정보 조회하기");
		list = session.getMapper(cls).select_like("김");
		for(Student s : list) System.out.println(s);
    System.out.println("이름에 김자가 들어가는 학생 정보 조회하기2");
		list = session.getMapper(cls).select_like("%김%");
		for(Student s : list) System.out.println(s);
	}
}

 

 

📌 StudentMapper.java -interface로 생성

package mapper;

import java.util.List;
import org.apache.ibatis.annotations.Select;
import main.Student;

public interface StudentMapper {
	/*
	 * db의 컬럼명과 Student의 프로퍼티를 비교하여 같은 이름의 데이터를 저장
	 */
	@Select("select * from student")
	public List<Student> select();

	@Select("select * from student where grade = #{value}")
	public List<Student> select_grade(int grade);

	@Select("select * from student where studno = #{value}")
	public List<Student> select_studno(String studno);

	@Select("select * from student where name like '%${value}%'")
	public List<Student> select_like(String name);

  @Select("select * from student where name like #{value}")
	public List<Student> select_like2(String name);
	/*
	 *  #{value} : 매개변수의 값 + 자료형을 인식함.
	 *              where name =#{value} => where name= '홍길동'
	 *              where name like %#{value}%
	 *                  -> where name like %'김'%
	 *              where name like '%#{value}%'    
	 *                  -> where name like '%'김'%'
	 *  ${value} : 매개변수의 값 =>  값만 치환 가능
	 *              where name=${value} => where name = 홍길동
	 *              where name like '%${value}%'
	 *                  -> where name like '%김%'
	 */
}

 

 

📌 Student.java

package main;

import java.util.Date;

public class Student {
	private int studno;
	private String name;
	private String id;
	private int grade;
	private String jumin;
	private Date birthday;
	private String tel;
	private int height;
	private int weight;
	private int deptno1;
	private int deptno2;
	private int profno;
	
	//getter, setter, toString
	public int getStudno() {
		return studno;
	}
	public void setStudno(int studno) {
		this.studno = studno;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public int getGrade() {
		return grade;
	}
	public void setGrade(int grade) {
		this.grade = grade;
	}
	public String getJumin() {
		return jumin;
	}
	public void setJumin(String jumin) {
		this.jumin = jumin;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getTel() {
		return tel;
	}
	public void setTel(String tel) {
		this.tel = tel;
	}
	public int getHeight() {
		return height;
	}
	public void setHeight(int height) {
		this.height = height;
	}
	public int getWeight() {
		return weight;
	}
	public void setWeight(int weight) {
		this.weight = weight;
	}
	public int getDeptno1() {
		return deptno1;
	}
	public void setDeptno1(int deptno1) {
		this.deptno1 = deptno1;
	}
	public int getDeptno2() {
		return deptno2;
	}
	public void setDeptno2(int deptno2) {
		this.deptno2 = deptno2;
	}
	public int getProfno() {
		return profno;
	}
	public void setProfno(int profno) {
		this.profno = profno;
	}
	@Override
	public String toString() {
		return "Student [studno=" + studno + ", name=" + name + ", id=" + id + ", grade=" + grade + ", jumin=" + jumin
				+ ", birthday=" + birthday + ", tel=" + tel + ", height=" + height + ", weight=" + weight + ", deptno1="
				+ deptno1 + ", deptno2=" + deptno2 + ", profno=" + profno + "]";
	}
	
	
}