[Hibernate] - many to one

Hibernate的多对一操作：

例子参考引用：

http://www.tutorialspoint.com/hibernate/hibernate_many_to_one_mapping.htm

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 resource="com/my/hbm/User.hbm.xml"/>
        <mapping resource="com/my/hbm/UserAccount.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

User.hbm.xml

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

    <class name="com.my.bean.User" table="user">
        <id name="id" type="int">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String" length="50">
            <column name="name" not-null="true" length="50" />
        </property>
        <property name="age" type="int">
            <column name="age" />
        </property>
        <property name="password" type="java.lang.String" length="50">
            <column name="password" length="50" />
        </property>
        <property name="email" type="java.lang.String" length="100">
            <column name="email" length="100" />
        </property>
        <property name="createtime" type="java.util.Date">
            <column name="createtime" />
        </property>
    </class>

</hibernate-mapping>

UserAccount.hbm.xml

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

    <class name="com.my.bean.UserAccount" table="user_account">
        <id name="id" type="int">
            <column name="id" />
            <generator class="native" />
        </id>
        <many-to-one name="user" column="user_id" class="com.my.bean.User" not-null="true"></many-to-one>
        <property name="account" type="java.lang.String" length="50">
            <column name="account" not-null="true" length="50" />
        </property>
    </class>

</hibernate-mapping>

Java Bean: User.java

package com.my.bean;

import java.util.Date;

public class User {
    private int id;
    private String name;
    private int age;
    private String password;
    private String email;
    private Date createtime;

    public int getId() {
        return id;
    }
    public void setId(int 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 String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public Date getCreatetime() {
        return createtime;
    }
    public void setCreatetime(Date createtime) {
        this.createtime = createtime;
    }
}

Java Bean: UserAccount.java

package com.my.bean;

public class UserAccount {

    private int id;
    private String account;
    private User user;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getAccount() {
        return account;
    }
    public void setAccount(String account) {
        this.account = account;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }

}

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;
    }

}

测试：

package com.my.init;

import java.util.Date;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;

import com.my.bean.User;
import com.my.bean.UserAccount;
import com.my.dao.util.HibernateUtil;

public class Test {

    public static void main(String[] args) {
        Test t = new Test();

        // Add new user
        User user = t
                .addUser("robin", "abcd1234", "robin@88db.com", new Date());
        System.out.println(user.getId());

        // Get user list
        List<User> users = t.listUser();
        for (User item : users) {
            System.out.println("User name: " + item.getName());
        }

        // Add UserAccount
        UserAccount ua = t.addUserAccount("robinzhang", user);
        System.out.println("Add UserAccount: " + ua.getId());

        // Update UserAccount
        UserAccount ua_u = t.updateUserAccount(ua.getId(), "robin_zhang");
        System.out.println("Update UserAccount: " + ua_u.getAccount());

        // Get User Account List
        List<UserAccount> uas = t.listUserAccount();
        for (UserAccount item : uas) {
            System.out.println("UserAccount: " + item.getAccount());
            System.out.println("UserID: " + item.getUser().getId());
        }

        // Delete UserAccount
        boolean result = t.deleteUserAccount(1);
        System.out.println("Delete UserAccount: " + result);

        // Delete User
        result = t.deleteUser(user);
        System.out.println("Delete User: " + result);
    }

    /**
     * List Users
     */
    @SuppressWarnings("unchecked")
    public List<User> listUser() {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        List<User> users = null;
        try {
            // Select action
            String hqlSelect = "from User where name like :name";
            Query query = session.createQuery(hqlSelect);
            query.setParameter("name", "%ro%");
            users = query.list();
            session.getTransaction().commit();
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }
        return users;
    }

    /**
     * Add new user
     *
     * @param name
     *            User name
     * @param password
     *            User password
     * @param email
     *            User email
     * @param createtime
     *            User create time
     * @return User object
     */
    public User addUser(String name, String password, String email,
            Date createtime) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        User u = new User();
        try {
            u.setName(name);
            u.setPassword(password);
            u.setCreatetime(createtime);
            u.setEmail(email);
            u.setAge(18);
            // Get new user id
            Integer userid = (Integer) session.save(u);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return u;
    }

    /**
     * Get UserAccount Object
     *
     * @param account
     *            account name
     * @param user
     *            User ID
     * @return UserAccount object
     */
    public UserAccount addUserAccount(String account, User user) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        UserAccount ua = null;
        try {
            ua = new UserAccount();
            ua.setAccount(account);
            ua.setUser(user);
            session.save(ua);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return ua;
    }

    /**
     * Get User Account List
     *
     * @return
     */
    @SuppressWarnings("unchecked")
    public List<UserAccount> listUserAccount() {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        List<UserAccount> uas = null;
        try {
            String hqlSelect = "from UserAccount where account like :account";
            Query query = session.createQuery(hqlSelect);
            query.setParameter("account", "%ro%");
            uas = query.list();
            session.getTransaction().commit();
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return uas;
    }

    /**
     * Update User Account
     *
     * @param id
     * @param account
     */
    public UserAccount updateUserAccount(Integer id, String account) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        UserAccount ua = null;
        try {
            ua = (UserAccount) session.get(UserAccount.class, id);
            ua.setAccount(account);
            session.update(ua);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return ua;
    }

    /**
     * Delete UserAccount
     *
     * @param id
     * @return true/false
     */
    public boolean deleteUserAccount(Integer id) {
        boolean result = false;
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        try {
            UserAccount ua = (UserAccount) session.get(UserAccount.class, id);
            session.delete(ua);
            session.getTransaction().commit();
            result = true;
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return result;
    }

    /**
     * Delete User
     *
     * @param user
     * @return
     */
    public boolean deleteUser(User user) {
        boolean result = false;
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();

        try {
            session.delete(user);
            session.getTransaction().commit();
            result = true;
        } catch (HibernateException e) {
            if (session.getTransaction() != null)
                session.getTransaction().rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return result;
    }

}

使用Hibernate会自动建库。