Hibernate – 多対多の例（注釈）

投稿日: 2019-11-05 2019-11-05
タグ: Hibernate, many-to-many

このチュートリアルでは、これまでの ”

Hibernate many to many example – XML mapping

“チュートリアルのインフラストラクチャ全体を再利用し、Hibernare/JPA注釈。

プロジェクト構造

このチュートリアルの新しいプロジェクト構造を見直してください。

多対多のプロジェクトフォルダ、title = "多対多アノテーションプロジェクトフォルダ"、幅= 475、高さ= 447

1. “多対多”テーブル関係

以前の多対多テーブル関係を再度参照してください。

多対多ER図、タイトル= "多対多図"、幅= 640、高さ= 193

2. Hibernateモデルクラス

以前のモデルクラス
Stock.java`と
Category.java`を更新し、新しい注釈コードを内部で定義します。

File:Stock.java

package com.mkyong.stock;

import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.CascadeType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

@Entity
@Table(name = "stock", catalog = "mkyongdb", uniqueConstraints = {
        @UniqueConstraint(columnNames = "STOCK__NAME"),
        @UniqueConstraint(columnNames = "STOCK__CODE") })
public class Stock implements java.io.Serializable {

    private Integer stockId;
    private String stockCode;
    private String stockName;
    private Set<Category> categories = new HashSet<Category>(0);

    public Stock() {
    }

    public Stock(String stockCode, String stockName) {
        this.stockCode = stockCode;
        this.stockName = stockName;
    }

    public Stock(String stockCode, String stockName, Set<Category> categories) {
        this.stockCode = stockCode;
        this.stockName = stockName;
        this.categories = categories;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "STOCK__ID", unique = true, nullable = false)
    public Integer getStockId() {
        return this.stockId;
    }

    public void setStockId(Integer stockId) {
        this.stockId = stockId;
    }

    @Column(name = "STOCK__CODE", unique = true, nullable = false, length = 10)
    public String getStockCode() {
        return this.stockCode;
    }

    public void setStockCode(String stockCode) {
        this.stockCode = stockCode;
    }

    @Column(name = "STOCK__NAME", unique = true, nullable = false, length = 20)
    public String getStockName() {
        return this.stockName;
    }

    public void setStockName(String stockName) {
        this.stockName = stockName;
    }

    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinTable(name = "stock__category", catalog = "mkyongdb", joinColumns = {
            @JoinColumn(name = "STOCK__ID", nullable = false, updatable = false) },
            inverseJoinColumns = { @JoinColumn(name = "CATEGORY__ID",
                    nullable = false, updatable = false) })
    public Set<Category> getCategories() {
        return this.categories;
    }

    public void setCategories(Set<Category> categories) {
        this.categories = categories;
    }

}

File:Category.java

package com.mkyong.stock;

import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name = "category", catalog = "mkyongdb")
public class Category implements java.io.Serializable {

    private Integer categoryId;
    private String name;
    private String desc;
    private Set<Stock> stocks = new HashSet<Stock>(0);

    public Category() {
    }

    public Category(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }

    public Category(String name, String desc, Set<Stock> stocks) {
        this.name = name;
        this.desc = desc;
        this.stocks = stocks;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "CATEGORY__ID", unique = true, nullable = false)
    public Integer getCategoryId() {
        return this.categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }

    @Column(name = "NAME", nullable = false, length = 10)
    public String getName() {
        return this.name;
    }

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

    @Column(name = "[DESC]", nullable = false)
    public String getDesc() {
        return this.desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @ManyToMany(fetch = FetchType.LAZY, mappedBy = "categories")
    public Set<Stock> getStocks() {
        return this.stocks;
    }

    public void setStocks(Set<Stock> stocks) {
        this.stocks = stocks;
    }

}

3.ハイバネート設定ファイル

Stock.java`と
Category.java`の注釈付きクラスを `hibernate.cfg.xml`に次のように挿入します:

File:hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
    <property name="hibernate.connection.driver__class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/mkyongdb</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">password</property>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="show__sql">true</property>
    <mapping class="com.mkyong.stock.Stock"/>
    <mapping class="com.mkyong.stock.Category"/>
</session-factory>
</hibernate-configuration>

4.それを実行する

それを実行すると、結果は自明です。

File:App.java

package com.mkyong;

import java.util.HashSet;
import java.util.Set;
import org.hibernate.Session;
import com.mkyong.stock.Category;
import com.mkyong.stock.Stock;
import com.mkyong.util.HibernateUtil;

public class App {
    public static void main(String[]args) {

        System.out.println("Hibernate many to many (Annotation)");
    Session session = HibernateUtil.getSessionFactory().openSession();

    session.beginTransaction();

    Stock stock = new Stock();
        stock.setStockCode("7052");
        stock.setStockName("PADINI");

        Category category1 = new Category("CONSUMER", "CONSUMER COMPANY");
        Category category2 = new Category("INVESTMENT", "INVESTMENT COMPANY");

        Set<Category> categories = new HashSet<Category>();
        categories.add(category1);
        categories.add(category2);

        stock.setCategories(categories);

        session.save(stock);

    session.getTransaction().commit();
    System.out.println("Done");
    }
}

出力

Hibernate many to many (Annotation)
Hibernate:
    insert
    into
        mkyongdb.stock
        (STOCK__CODE, STOCK__NAME)
    values
        (?, ?)
Hibernate:
    insert
    into
        mkyongdb.category
        (`DESC`, NAME)
    values
        (?, ?)
Hibernate:
    insert
    into
        mkyongdb.category
        (`DESC`, NAME)
    values
        (?, ?)
Hibernate:
    insert
    into
        mkyongdb.stock__category
        (STOCK__ID, CATEGORY__ID)
    values
        (?, ?)
Hibernate:
    insert
    into
        mkyongdb.stock__category
        (STOCK__ID, CATEGORY__ID)
    values
        (?, ?)
Done

それをダウンロードする –

Hibernate-many-to-many-annotation.zip

（9KB）

リファレンス

http://docs.jboss.org/hibernate/core/3.6/reference/en-US/html/associations.html#assoc-unidirectional-join-m2m

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