Hibernate使用Annotation的一对多:
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> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://127.0.0.1/testdb</property> <property name="connection.username">root</property> <property name="connection.password"></property> <!-- JDBC connection pool (use the built-in) --> <property name="connection.pool_size">1</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property> <!-- Enable Hibernate‘s automatic session context management --> <property name="current_session_context_class">thread</property> <!-- Disable the second-level cache --> <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <!-- Drop and re-create the database schema on startup --> <property name="hbm2ddl.auto">update</property> <mapping class="com.my.bean.User"/> <mapping class="com.my.bean.UserCard"/> </session-factory> </hibernate-configuration>
HibernateUtil.java
package com.my.dao.util; import org.hibernate.SessionFactory; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; import org.hibernate.cfg.Configuration; public class HibernateUtil { private static final SessionFactory sessionFactory = buildSessionFactory(); private static SessionFactory buildSessionFactory() { try { // Create the SessionFactory from hibernate.cfg.xml Configuration configuration = new Configuration(); return configuration.configure().buildSessionFactory( new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build()); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { return sessionFactory; } }
Java Beans
package com.my.bean; import java.util.Date; import java.util.Set; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Table; @Entity @Table(name="user") public class User { @Id @GeneratedValue @Column(name="user_id", nullable=false) private long userID; @Column(name="user_name", length=100, nullable=false) private String userName; @Column(name="create_time", nullable=false) private Date createTime; @OneToMany(mappedBy="user", cascade=CascadeType.ALL) private Set<UserCard> cards; public long getUserID() { return userID; } public void setUserID(long userID) { this.userID = userID; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } public Set<UserCard> getCards() { return cards; } public void setCards(Set<UserCard> cards) { this.cards = cards; } }
package com.my.bean; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table; @Entity @Table(name="user_card") public class UserCard { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="card_id") private long cardID; @Column(name="card_name") private String CardName; @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="user_id") private User user; public long getCardID() { return cardID; } public void setCardID(long cardID) { this.cardID = cardID; } public String getCardName() { return CardName; } public void setCardName(String cardName) { CardName = cardName; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } }
测试:
package com.my.init; import java.util.Date; import java.util.HashSet; import org.hibernate.Session; import org.hibernate.Transaction; import com.my.bean.User; import com.my.bean.UserCard; import com.my.dao.util.HibernateUtil; public class Test { public static void main(String[] args) { Session session = HibernateUtil.getSessionFactory().openSession(); Transaction tx = session.beginTransaction(); try { //--------------------------------------------------- // add user //--------------------------------------------------- User user = new User(); user.setUserName("Robin"); user.setCreateTime(new Date()); user.setCards(new HashSet<UserCard>()); //--------------------------------------------------- // add card //--------------------------------------------------- UserCard cardBBC = new UserCard(); cardBBC.setCardName("BCC"); cardBBC.setUser(user); UserCard cardCBC = new UserCard(); cardCBC.setCardName("CBC"); cardCBC.setUser(user); // add cards to user user.getCards().add(cardBBC); user.getCards().add(cardCBC); //--------------------------------------------------- // save //-------------------------------------------------- session.save(user); //--------------------------------------------------- // remove user //--------------------------------------------------- session.delete(user); tx.commit(); } catch (Exception e) { tx.rollback(); e.printStackTrace(); } session.close(); } }
时间: 2024-10-29 04:51:13