Hibernate详细教程

1.在src目录下创建hibernate.cfg.xml配置文件

PS:文件的名字不能改！

    

        
        root
        1234
        com.mysql.jdbc.Driver
        jdbc:mysql://localhost:3306/test

        
        
        org.hibernate.dialect.MySQL5InnoDBDialect

        true
     
        update
        
        
        none
    
    

2. 编写实体类，以Person类为例

package test.Hibernate.model;

import java.util.HashSet;
import java.util.Set;

public class Person {
    @Override
    public String toString() {
        return "Person [id=" + id + ", name=" + name + "]";
    }
    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 Set getAddress() {
        return address;
    }
    public void setAddress(Set address) {
        this.address = address;
    }
    private int id;
    private String name;
    private Set address = new HashSet();
      
}

3.编写Person.hbm.xml实体类配置文件

4.在hibernate.cfg.xml中加入映射信息

5.使用MyEclipse生成SessionFactory

package test.Hibernate.SessionFactory;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

/**
 * Configures and provides access to Hibernate sessions, tied to the
 * current thread of execution.  Follows the Thread Local Session
 * pattern, see {@link http://hibernate.org/42.html }.
 */
public class SessionFactory {

    /** 
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses  
     * #resourceAsStream style lookup for its configuration file. 
     * The default classpath location of the hibernate config file is 
     * in the default package. Use #setConfigFile() to update 
     * the location of the configuration file for the current session.   
     */
    private static final ThreadLocal threadLocal = new ThreadLocal();
    private static org.hibernate.SessionFactory sessionFactory;
    
    private static Configuration configuration = new Configuration();
    private static ServiceRegistry serviceRegistry; 

    static {
        try {
            configuration.configure();
            serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry();
            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }
    private SessionFactory() {
    }
    
    /**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the SessionFactory if needed.
     *
     *  @return Session
     *  @throws HibernateException
     */
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();

        if (session == null || !session.isOpen()) {
            if (sessionFactory == null) {
                rebuildSessionFactory();
            }
            session = (sessionFactory != null) ? sessionFactory.openSession()
                    : null;
            threadLocal.set(session);
        }

        return session;
    }

    /**
     *  Rebuild hibernate session factory
     *
     */
    public static void rebuildSessionFactory() {
        try {
            configuration.configure();
            serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry();
            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

    /**
     *  Close the single hibernate session instance.
     *
     *  @throws HibernateException
     */
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);

        if (session != null) {
            session.close();
        }
    }

    /**
     *  return session factory
     *
     */
    public static org.hibernate.SessionFactory getSessionFactory() {
        return sessionFactory;
    }
    /**
     *  return hibernate configuration
     *
     */
    public static Configuration getConfiguration() {
        return configuration;
    }

}

6.编写测试类

package test.Hibernate.dao;

import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import test.Hibernate.SessionFactory.SessionFactory;
import test.Hibernate.model.Person;

public class PersonDao {
    @Test
    public void add(){
        Session session = SessionFactory.getSession();
        Transaction tr = session.beginTransaction();
        //----------------------------------------------
        
        Person p = new Person();
        p.setName("test");
        p.getAddress().add("firstAddr");
        p.getAddress().add("secondAddr");
        p.getAddress().add("thirdAddr");
        p.getAddress().add("fourthAddr");        
        session.save(p);
        
        //----------------------------------------------
        tr.commit();
        SessionFactory.closeSession();
        
    }
    
    @Test
    public void get(){
        Session session = SessionFactory.getSession();
        Transaction tr = session.beginTransaction();
        //----------------------------------------------
        
        Person p = (Person)session.get(Person.class, 2);
        System.out.println(p);
        
        //----------------------------------------------
        tr.commit();
        SessionFactory.closeSession();
    }
}

identity：使用数据库的自动增长策略，不是所有数据库都支持，比如oracle就不支持。

sequence：在 DB2，PostgreSQL，Oracle，SAP DB，McKoi 中使用序列（sequence）在使用Oracle数据库时可以使用这一个。

hilo:使用高低位算法生成主键值。只需要一张额外表，所有的数据都支持。

native:根据底层数据库的能力选择 identity、sequence 或者 hilo中的一个。

assigned：手工指定主键值。

uuid：由Hibernate自动生成UUID并指定为主键值。

1.一对一映射（以主键关联作为示例）User与IdCard（有外键方）的XML配置：

    
        
            
                user
            
        
                
        
        
    

2.一对多，多对一（以Father和Children为例）

3.多对多（以Student和Teacher为例）

PS:有一方的set集合要标明inverse=true（后面会讲）

1.inverse=false在一对多删除时是把孩子的外键设置为null，然后删除父亲，孩子不删除，而casecade=all在一对多删除时是把孩子的外键设置为null，然后删除父亲，然后再删除孩子

2.many to many的时候由一方维护，所以一方要设置inverse=false，但是inverse=true的另一方直接删除会出错，这个时候可以用casecade完成级联删除

3.inverse=false只用于set等集合属性，在one to one关系中可以用casecade完成级联删除

1.需要额外导入3个jar包

2.在hibernate.cfg.xml中加入C3P0配置信息

        
        org.hibernate.connection.C3P0ConnectionProvider
        
        5
        
        20
        
        120
         
        3000

@Test
    public void HQLSearch(){
        Session session = SessionFactory.getSession();
        Transaction tr = session.beginTransaction();
        //-----------------------------------------
        
        //common search with where
//        String hql= "select e.id,e.name from User e where e.id>=5 and e.id<=9";
//        Query query = session.createQuery(hql);
//        List list = query.list();        
//        for(Object o : list){            
//            System.out.println(Arrays.toString((Object[])o));
//        }
        
        //paging search
//        String hql= "select e.id,e.name from User e";
//        Query query = session.createQuery(hql);
//        query.setFirstResult(0);
//        query.setMaxResults(10);
//        List list = query.list();        
//        for(Object o : list){            
//            System.out.println(Arrays.toString((Object[])o));
//        }
        
        //search with parameters
//        String hql= "select e.id,e.name from User e where id>=? and id<=?";
//        Query query = session.createQuery(hql)
//                .setParameter(0, 1)
//                .setParameter(1, 3);
//        List list = query.list();        
//        for(Object o : list){            
//            System.out.println(Arrays.toString((Object[])o));
//        }
        
        //search with parameters whose type is collection
//        String hql= "select e.id,e.name from User e where id in (:ids)";
//        Query query = session.createQuery(hql)
//                .setParameterList("ids",new Object[]{1,2,3,8} );
//        List list = query.list();    
//        for(Object o : list){            
//            System.out.println(Arrays.toString((Object[])o));
//        }
        
        
        //-----------------------------------------
        tr.commit();
        SessionFactory.closeSession();
    }

@Test
    public void DML(){
        Session session = SessionFactory.getSession();
        Transaction tr = session.beginTransaction();
        //-----------------------------------------
        User u = (User)session.get(User.class, 11);
        
        String sql = "update User set name=? where id>?";
        int result = session.createQuery(sql)
                .setParameter(0, "updated")
                .setParameter(1, 10)
                .executeUpdate();
        System.out.println("count of update:"+result);
        
        //the object's status in session was not updated when the object in database have been changed,so if you want
        //to get the updated object in session,you should use method "refresh".
        session.refresh(u);
        
        System.out.println(u);
        
        //-----------------------------------------
        tr.commit();
        SessionFactory.closeSession();
    }

1. 需要导入以下jar包

2.在hibernate.cfg.xml中加入以下配置

         
        true  
        org.hibernate.cache.ehcache.EhCacheRegionFactory
        
        true