[자바교육,스프링교육,JPA교육학원_탑크리에듀]@OneToMany,@ManyToOne 컬렉션에서 Map, MapKeyColumn 사용예문

@OneToMany,@ManyToOne 컬렉션에서 Map, MapKeyColumn 사용예문 

열공하세요~

1. Emp.java

package demo.model;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.ManyToOne;

import javax.persistence.Table;

import lombok.Getter;

import lombok.RequiredArgsConstructor;

import lombok.Setter;

import lombok.ToString;

@Entity

@Table(name = "emp")

@RequiredArgsConstructor

@Getter

@Setter

@ToString

public class Emp {

@Id

@GeneratedValue

private Long empno;

private final String ename;

@ManyToOne

@JoinColumn(name = "deptno")

private final Dept dept;

public Emp(String ename) {

this.ename = ename;

dept = null;

}

}

2. Dept.java

package demo.model;

import java.util.HashMap;

import java.util.Map;

import javax.persistence.CascadeType;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.MapKeyColumn;

import javax.persistence.OneToMany;

import javax.persistence.Table;

import lombok.Getter;

import lombok.NonNull;

import lombok.RequiredArgsConstructor;

import lombok.Setter;

import lombok.ToString;

@Entity

@Table(name = "dept")

@RequiredArgsConstructor

@Getter

@Setter

@ToString(exclude="emps")

public class Dept {

@Id

@GeneratedValue

private Long deptno;

@NonNull

private String dname;

@NonNull

@OneToMany(mappedBy = "dept", cascade = CascadeType.ALL)

@MapKeyColumn(name = "id", nullable=true)

private Map<Integer, Emp> emps;

public Dept(String dname) {

this.dname = dname;

emps = null;

}

}

3. DeptRepository.java

package demo.repository;

import org.springframework.data.jpa.repository.JpaRepository;

import demo.model.Dept;

public interface DeptRepository extends JpaRepository<Dept, Long> {

}

4.  스프링 부트 메인 ManytooneApplication.java

package demo;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

import javax.persistence.EntityManager;

import javax.persistence.PersistenceContext;

import javax.transaction.Transactional;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import demo.model.Dept;

import demo.model.Emp;

import demo.repository.DeptRepository;

@SpringBootApplication

public class ManytooneApplication implements CommandLineRunner {

private static final Logger logger = LoggerFactory.getLogger(ManytooneApplication.class);

@Autowired

private DeptRepository deptRepository;

@PersistenceContext

private EntityManager em;

public static void main(String[] args) {

SpringApplication.run(ManytooneApplication.class, args);

}

@Override

@Transactional

public void run(String...strings) throws Exception {

//Dept에 1번부서가 만들어지고, Emp의 deptno는 1로 입력됨

Dept d1 = new Dept("교육팀");

Emp e1 = new Emp("김교육", d1);

Emp e2 = new Emp("나교육", d1);

d1.setEmps(new HashMap<Integer, Emp>() {

  {

put(1, e1);

put(2, e2);

  }

});

//Dept에 2번 부서가 만들어지고 Emp의 deptno는 NULL로 입력

Dept d2 = new Dept("개발팀", new HashMap<Integer, Emp>() {

  {

put(1, new Emp("김개발"));

put(2, new Emp("나개발"));

  }

});

//Dept, Emp 저장

deptRepository.save(new HashSet<Dept>() {

  {

add(d1);

add(d2);

  }

});

for(Dept d : deptRepository.findAll()) {

if (d != null) {

logger.info(d.toString());

}

}

//------------- 1번 부서 및 부서원 로드

Dept d3 = deptRepository.findOne(1L);

Map<Integer, Emp> emps = d3.getEmps();

for(Map.Entry<Integer, Emp> entry : emps.entrySet()) {

logger.info("[" + entry.getKey() + ":" + entry.getValue() + "]");

}

//------------- 1번부서 삭제, 1번부서원들도 같이 삭제된다.

deptRepository.delete(d3);

}

}