Hibernate – One-to-Many example (Annotation)

In this tutorial, it will reuse the entire infrastructure of the previous “Hibernate one to many relationship example – XML mapping” tutorial, enhance it to support Hibernate / JPA annotation.

Project Structure
Review the new project structure of this tutorial.

Note
Since Hibernate 3.6, annotation codes are merged into the Hibernate core module, so, the previous pom.xml file can be reuse.

1. “One-to-many” table relationship

See the previous one to many table relationship again.

2. Hibernate Model Class

Update previous model classes – Stock.java and StockDailyRecord.java, and define the annotation code inside.

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.Id;import javax.persistence.OneToMany;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<StockDailyRecord> stockDailyRecords = new HashSet<StockDailyRecord>(            0);    public Stock() {    }    public Stock(String stockCode, String stockName) {        this.stockCode = stockCode;        this.stockName = stockName;    }    public Stock(String stockCode, String stockName,            Set<StockDailyRecord> stockDailyRecords) {        this.stockCode = stockCode;        this.stockName = stockName;        this.stockDailyRecords = stockDailyRecords;    }    @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;    }    @OneToMany(fetch = FetchType.LAZY, mappedBy = "stock")    public Set<StockDailyRecord> getStockDailyRecords() {        return this.stockDailyRecords;    }    public void setStockDailyRecords(Set<StockDailyRecord> stockDailyRecords) {        this.stockDailyRecords = stockDailyRecords;    }}

File : StockDailyRecord.java

package com.mkyong.stock;import java.util.Date;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.JoinColumn;import javax.persistence.ManyToOne;import javax.persistence.Table;import javax.persistence.Temporal;import javax.persistence.TemporalType;import javax.persistence.UniqueConstraint;@Entity@Table(name = "stock_daily_record", catalog = "mkyongdb", uniqueConstraints = @UniqueConstraint(columnNames = "DATE"))public class StockDailyRecord implements java.io.Serializable {    private Integer recordId;    private Stock stock;    private Float priceOpen;    private Float priceClose;    private Float priceChange;    private Long volume;    private Date date;    public StockDailyRecord() {    }    public StockDailyRecord(Stock stock, Date date) {        this.stock = stock;        this.date = date;    }    public StockDailyRecord(Stock stock, Float priceOpen, Float priceClose,            Float priceChange, Long volume, Date date) {        this.stock = stock;        this.priceOpen = priceOpen;        this.priceClose = priceClose;        this.priceChange = priceChange;        this.volume = volume;        this.date = date;    }    @Id    @GeneratedValue(strategy = IDENTITY)    @Column(name = "RECORD_ID", unique = true, nullable = false)    public Integer getRecordId() {        return this.recordId;    }    public void setRecordId(Integer recordId) {        this.recordId = recordId;    }    @ManyToOne(fetch = FetchType.LAZY)    @JoinColumn(name = "STOCK_ID", nullable = false)    public Stock getStock() {        return this.stock;    }    public void setStock(Stock stock) {        this.stock = stock;    }    @Column(name = "PRICE_OPEN", precision = 6)    public Float getPriceOpen() {        return this.priceOpen;    }    public void setPriceOpen(Float priceOpen) {        this.priceOpen = priceOpen;    }    @Column(name = "PRICE_CLOSE", precision = 6)    public Float getPriceClose() {        return this.priceClose;    }    public void setPriceClose(Float priceClose) {        this.priceClose = priceClose;    }    @Column(name = "PRICE_CHANGE", precision = 6)    public Float getPriceChange() {        return this.priceChange;    }    public void setPriceChange(Float priceChange) {        this.priceChange = priceChange;    }    @Column(name = "VOLUME")    public Long getVolume() {        return this.volume;    }    public void setVolume(Long volume) {        this.volume = volume;    }    @Temporal(TemporalType.DATE)    @Column(name = "DATE", unique = true, nullable = false, length = 10)    public Date getDate() {        return this.date;    }    public void setDate(Date date) {        this.date = date;    }}

3. Hibernate Configuration File

Puts annotated classes Stock.java and StockDailyRecord.java in hibernate.cfg.xml like this :

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.StockDailyRecord" /></session-factory></hibernate-configuration>

4. Run It

Run it, Hibernate will insert a row into the STOCK table and a row into the STOCK_DAILY_RECORD table.

File : App.java

package com.mkyong;import java.util.Date;import org.hibernate.Session;import com.mkyong.stock.Stock;import com.mkyong.stock.StockDailyRecord;import com.mkyong.util.HibernateUtil;public class App {    public static void main(String[] args) {        System.out.println("Hibernate one to many (Annotation)");    Session session = HibernateUtil.getSessionFactory().openSession();    session.beginTransaction();    Stock stock = new Stock();        stock.setStockCode("7052");        stock.setStockName("PADINI");        session.save(stock);        StockDailyRecord stockDailyRecords = new StockDailyRecord();        stockDailyRecords.setPriceOpen(new Float("1.2"));        stockDailyRecords.setPriceClose(new Float("1.1"));        stockDailyRecords.setPriceChange(new Float("10.0"));        stockDailyRecords.setVolume(3000000L);        stockDailyRecords.setDate(new Date());        stockDailyRecords.setStock(stock);                stock.getStockDailyRecords().add(stockDailyRecords);        session.save(stockDailyRecords);    session.getTransaction().commit();    System.out.println("Done");    }}

Output

Hibernate one to many (Annotation)Hibernate:     insert     into        mkyongdb.stock        (STOCK_CODE, STOCK_NAME)     values        (?, ?)Hibernate:     insert     into        mkyongdb.stock_daily_record        (DATE, PRICE_CHANGE, PRICE_CLOSE, PRICE_OPEN, STOCK_ID, VOLUME)     values        (?, ?, ?, ?, ?, ?)

Done