反向工程:先创建表,创建好表之后,就是持久化类和映射文件可以不用你写,而且你的DAO它也可以帮你生成。但是它生成的DAO可能会多很多的方法。你可以不用那么多方法,但是它里面提供了这种的。用hibernate,必须得用myeclipse里面的这种自动生成的工具。其实myeclipse它里面对Struts和Spring都有集成。但是这种集成对三大框架整合的时候会有问题。
用hibernate的时候最好先建一个连接数据库的模板。这个时候它可以帮我们把核心配置文件hibernate.cfg.xml中的参数全部设置好。如果你没有hibernate.cfg.xml这个模板的话,它最多帮你把hibernate的jar包拷贝过来。最多能帮你创建一个工具类HibernateUtils.java。如果你把hibernate.cfg.xml创建好了,它可以帮你把核心配置文件中的参数设置好。
回到MyEclipse Database Explorer Perspective,选择数据库表右键逆向工程生成类和映射文件。是把表全选之后再Hibernate Reverse Engineering
你自己引jar包是不能反向工程的,只能使用MyEclipse的hibernate支持才可以反向工程。使用hibernate支持的web工程和普通的web工程的logo都不一样。如果使用MyEclipse的hibernate、Struts、Spring的支持进行三大框架整合是会报错的,因为里面有很多重复的jar包。
package cn.itcast.utils;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
/**
* 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 HibernateSessionFactory {
/**
* 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 String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
private static Configuration configuration = new Configuration();
private static org.hibernate.SessionFactory sessionFactory;
private static String configFile = CONFIG_FILE_LOCATION;
static {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} catch (Exception e) {
System.err
.println("%%%% Error Creating SessionFactory %%%%");
e.printStackTrace();
}
}
private HibernateSessionFactory() {
}
/**
* Returns the ThreadLocal Session instance. Lazy initialize
* the <code>SessionFactory</code> if needed.
*
* @return Session
* @throws HibernateException
*/
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();//getSession是从当前线程往外取的.从当前线程获取session
//threadLocal获取当前线程的session 我们是getCurrentSession(),然后在核心配置文件还要配置一句
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ? sessionFactory.openSession()
: null;
threadLocal.set(session);//绑定到当前线程里面
}
return session;
}
/**
* Rebuild hibernate session factory
*
*/
public static void rebuildSessionFactory() {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} 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 session factory
*
* session factory will be rebuilded in the next call
*/
public static void setConfigFile(String configFile) {
HibernateSessionFactory.configFile = configFile;
sessionFactory = null;
}
/**
* return hibernate configuration
*
*/
public static Configuration getConfiguration() {
return configuration;
}
}
package cn.itcast.vo;
import java.util.List;
import java.util.Set;
import org.hibernate.LockMode;
import org.hibernate.Query;
import org.hibernate.criterion.Example;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A data access object (DAO) providing persistence and search support for
* Customer entities. Transaction control of the save(), update() and delete()
* operations can directly support Spring container-managed transactions or they
* can be augmented to handle user-managed Spring transactions. Each of these
* methods provides additional information for how to configure it for the
* desired type of transaction control.
*
* @see cn.itcast.vo.Customer
* @author MyEclipse Persistence Tools
*/
public class CustomerDAO extends BaseHibernateDAO {
private static final Logger log = LoggerFactory
.getLogger(CustomerDAO.class);
// property constants
public static final String CNAME = "cname";
public static final String AGE = "age";
public static final String VERSION = "version";
public void save(Customer transientInstance) {//保存Customer实例化
log.debug("saving Customer instance");
try {
getSession().save(transientInstance);
log.debug("save successful");
} catch (RuntimeException re) {
log.error("save failed", re);
throw re;
}
}
public void delete(Customer persistentInstance) {
log.debug("deleting Customer instance");
try {
getSession().delete(persistentInstance);
log.debug("delete successful");
} catch (RuntimeException re) {
log.error("delete failed", re);
throw re;
}
}
public Customer findById(java.lang.Integer id) {
log.debug("getting Customer instance with id: " + id);
try {
Customer instance = (Customer) getSession().get(
"cn.itcast.vo.Customer", id);
return instance;
} catch (RuntimeException re) {
log.error("get failed", re);
throw re;
}
}
public List findByExample(Customer instance) {
log.debug("finding Customer instance by example");
try {
List results = getSession().createCriteria("cn.itcast.vo.Customer")
.add(Example.create(instance)).list();
log.debug("find by example successful, result size: "
+ results.size());
return results;
} catch (RuntimeException re) {
log.error("find by example failed", re);
throw re;
}
}
public List findByProperty(String propertyName, Object value) {
log.debug("finding Customer instance with property: " + propertyName
+ ", value: " + value);
try {
String queryString = "from Customer as model where model."
+ propertyName + "= ?";
Query queryObject = getSession().createQuery(queryString);
queryObject.setParameter(0, value);
return queryObject.list();
} catch (RuntimeException re) {
log.error("find by property name failed", re);
throw re;
}
}
public List findByCname(Object cname) {
return findByProperty(CNAME, cname);
}
public List findByAge(Object age) {
return findByProperty(AGE, age);
}
public List findByVersion(Object version) {
return findByProperty(VERSION, version);
}
public List findAll() {
log.debug("finding all Customer instances");
try {
String queryString = "from Customer";
Query queryObject = getSession().createQuery(queryString);
return queryObject.list();
} catch (RuntimeException re) {
log.error("find all failed", re);
throw re;
}
}
public Customer merge(Customer detachedInstance) {
log.debug("merging Customer instance");
try {
Customer result = (Customer) getSession().merge(detachedInstance);
log.debug("merge successful");
return result;
} catch (RuntimeException re) {
log.error("merge failed", re);
throw re;
}
}
public void attachDirty(Customer instance) {
log.debug("attaching dirty Customer instance");
try {
getSession().saveOrUpdate(instance);
log.debug("attach successful");
} catch (RuntimeException re) {
log.error("attach failed", re);
throw re;
}
}
public void attachClean(Customer instance) {
log.debug("attaching clean Customer instance");
try {
getSession().lock(instance, LockMode.NONE);
log.debug("attach successful");
} catch (RuntimeException re) {
log.error("attach failed", re);
throw re;
}
}
}