실습 4 매핑 및 JPQL

Member.java

package com.ddoongi.web.entity;

import javax.persistence.*;
import java.util.Date;

@Entity // name 속성을 통해 JPQL에서도 다르게 쓰일 수 있다.
public class Member {

​​​​@Id @GeneratedValue
​​​​private long id;

​​​​private String name;

​​​​private int age;

​​​​@Column(name = "reg_date") @Temporal(TemporalType.DATE)
​​​​private Date regDate;

​​​​@Enumerated(EnumType.STRING)
​​​​private Tier tier;

​​​​@ManyToOne(fetch = FetchType.LAZY)
​​​​@JoinColumn
​​​​private Team team;

​​​​public Member() { }

​​​​public Member(String name, int age, Date regDate, Tier tier, Team team) {
​​​​​​​​this.name = name;
​​​​​​​​this.age = age;
​​​​​​​​this.regDate = regDate;
​​​​​​​​this.tier = tier;
​​​​​​​​this.team = team;
​​​​}

​​​​public long getId() {
​​​​​​​​return id;
​​​​}

​​​​public void setId(long id) {
​​​​​​​​this.id = id;
​​​​}

​​​​public String getName() {
​​​​​​​​return name;
​​​​}

​​​​public void setName(String name) {
​​​​​​​​this.name = name;
​​​​}

​​​​public int getAge() {
​​​​​​​​return age;
​​​​}

​​​​public void setAge(int age) {
​​​​​​​​this.age = age;
​​​​}

​​​​public Date getRegDate() {
​​​​​​​​return regDate;
​​​​}

​​​​public void setRegDate(Date regDate) {
​​​​​​​​this.regDate = regDate;
​​​​}

​​​​public Tier getTier() {
​​​​​​​​return tier;
​​​​}

​​​​public void setTier(Tier tier) {
​​​​​​​​this.tier = tier;
​​​​}

​​​​public Team getTeam() {
​​​​​​​​return team;
​​​​}

​​​​public void setTeam(Team team) {
​​​​​​​​this.team = team;
​​​​}

​​​​@Override
​​​​public String toString() {
​​​​​​​​return "Member{" +
​​​​​​​​​​​​​​​​"id=" + id +
​​​​​​​​​​​​​​​​", name='" + name + '\'' +
​​​​​​​​​​​​​​​​", age=" + age +
​​​​​​​​​​​​​​​​", regDate=" + regDate +
​​​​​​​​​​​​​​​​", tier=" + tier +
​​​​​​​​​​​​​​​​", team=" + team +
​​​​​​​​​​​​​​​​'}';
​​​​}
}

 

Team.java

package com.ddoongi.web.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import java.util.ArrayList;
import java.util.List;

@Entity
public class Team {

​​​​@Id @GeneratedValue
​​​​private long id;

​​​​private String name;

​​​​@OneToMany(mappedBy = "team")
​​​​private List<Member> members = new ArrayList<>();

​​​​public Team() { }

​​​​public Team(String name) {
​​​​​​​​this.name = name;
​​​​}

​​​​public long getId() {
​​​​​​​​return id;
​​​​}

​​​​public void setId(long id) {
​​​​​​​​this.id = id;
​​​​}

​​​​public String getName() {
​​​​​​​​return name;
​​​​}

​​​​public void setName(String name) {
​​​​​​​​this.name = name;
​​​​}

​​​​public List<Member> getMembers() {
​​​​​​​​return members;
​​​​}

​​​​public void setMembers(List<Member> members) {
​​​​​​​​this.members = members;
​​​​}

​​​​@Override
​​​​public String toString() {
​​​​​​​​return "Team{" +
​​​​​​​​​​​​​​​​"id=" + id +
​​​​​​​​​​​​​​​​", name='" + name + '\'' +
​​​​​​​​​​​​​​​​'}';
​​​​}
}

 

Tier.java

package com.ddoongi.web.entity;

public enum Tier {
​​​​DIAMOND,
​​​​PLATINUM,
​​​​GOLD,
​​​​SILVER,
​​​​BRONZE
}

 

Main.java

package com.ddoongi.web;

import com.ddoongi.web.entity.Member;
import com.ddoongi.web.entity.Team;
import com.ddoongi.web.entity.Tier;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import java.util.Date;
import java.util.List;

public class Main {
​​​​public static void main(String[] args) {
​​​​​​​​EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");

​​​​​​​​EntityManager em = emf.createEntityManager();

​​​​​​​​EntityTransaction tx = em.getTransaction();

​​​​​​​​tx.begin();

​​​​​​​​try {
​​​​​​​​​​​​Team team = new Team("Blue");
​​​​​​​​​​​​em.persist(team);

​​​​​​​​​​​​Member member1 = new Member("Alice", 22, new Date(), Tier.GOLD, team);
​​​​​​​​​​​​em.persist(member1);

​​​​​​​​​​​​Member member2 = new Member("Bianca", 23, new Date(), Tier.DIAMOND, team);
​​​​​​​​​​​​em.persist(member2);

​​​​​​​​​​​​Member member3 = new Member("Simon", 21, new Date(), Tier.GOLD, team);
​​​​​​​​​​​​em.persist(member3);

​​​​​​​​​​​​em.flush();
​​​​​​​​​​​​em.clear();

​​​​​​​​​​​​/* team.getMembers() */
​​​​​​​​​​​​Member findMember = em.find(Member.class, member1.getId());
​​​​​​​​​​​​Team findTeam = findMember.getTeam();

​​​​​​​​​​​​List<Member> members = findTeam.getMembers();
​​​​​​​​​​​​for (Member m : members) {
​​​​​​​​​​​​​​​​System.out.println(m);
​​​​​​​​​​​​}

​​​​​​​​​​​​/* JPQL */
​​​​​​​​​​​​String jpql = "SELECT m FROM Member m WHERE m.name LIKE '%e%'";
​​​​​​​​​​​​List<Member> result = em.createQuery(jpql, Member.class).getResultList();
​​​​​​​​​​​​for (Member m : result) {
​​​​​​​​​​​​​​​​System.out.println(m);
​​​​​​​​​​​​}

​​​​​​​​​​​​tx.commit();
​​​​​​​​} catch (Exception e) {
​​​​​​​​​​​​tx.rollback();
​​​​​​​​} finally {
​​​​​​​​​​​​em.close();
​​​​​​​​}

​​​​​​​​emf.close();
​​​​}
}