一个用myeclipse开发hibernate的入门例子

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hibernate

Hibernate Myeclipse MySQL XML JDBC

一、环境

1.eclipse 3.2.2
2.myeclipse 5.1.1
3.jdk 1.5

二、简要说明

数据库为mysql

在mysql中建立一个test数据库,建立cat表
CREATE TABLE `cat` (
`cat_id` varchar(32) NOT NULL,
`name` varchar(16) NOT NULL,
`sex` varchar(1) default NULL,
`weight` float(9,3) default NULL,
PRIMARY KEY (`cat_id`)
)

三、步骤

1.导入包的准备工作

a.新建java project.建立包example
在它下面编写类Cat.java

package example;

public class Cat implements java.io.Serializable {

// Fields

     private String catId;
     private String name;
     private String sex;
     private Float weight;

// Constructors

    /** default constructor */
    public Cat() {
    }

/** minimal constructor */
    public Cat(String name) {
        this.name = name;
    }

    /** full constructor */
    public Cat(String name, String sex, Float weight) {
        this.name = name;
        this.sex = sex;
        this.weight = weight;
    }

// Property accessors

    public String getCatId() {
        return this.catId;
    }

    public void setCatId(String catId) {
        this.catId = catId;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return this.sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Float getWeight() {
        return this.weight;
    }

    public void setWeight(Float weight) {
        this.weight = weight;
    }
}

同样在此包下面编写Cat.hbm.xml

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

<hibernate-mapping>
    <class name="example.Cat" table="cat" catalog="testhibernate">
        <id name="catId" type="java.lang.String">
            <column name="cat_id" length="32" />
            <generator class="uuid.hex"></generator>
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="16" not-null="true" />
        </property>
        <property name="sex" type="java.lang.String">
            <column name="sex" length="1" />
        </property>
        <property name="weight" type="java.lang.Float">
            <column name="weight" precision="9" scale="3" />
        </property>
    </class>
</hibernate-mapping>

b.在工程的src里面加入一个包，用来存放将要生成的HibernateSessionFactory。包名如（example.util）。
导入hibernate(生成的代码:
package example.util;

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;

    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();

  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(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;
}

}

对工程名点鼠标右键。选择myeclipse->add

hibernate capabicities。

在弹出的窗口选择中Hibernate 3.0 Core Libraries和Hibernate 3.0 Advanced Support Libraries

下面选中Copy checked Library Jars to project folder and add to build-path。点击下一步。

c.默认（hibernate cofig file），下一步。

d.选中User JDBC driver
connect url: jdbc:mysql://localhost:3306/test
Driver class: org.gjt.mm.mysql.Driver
username: root
password: ******
Dialect: mysql

e.在第一行包选择里面，选择在前面第二大步建的包如（example）。点击完成。

f.弹出的画面中选择properties的add按钮。在Property中加入show_sql，Value中加入true。点确定

保存设置。在mappings中点add加入前面建立的Cat.hbm.xml。最后生成的hibernate.cfg.xml文件如下
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>
<property name="connection.username">root</property>
<property name="connection.url">
  jdbc:mysql://localhost:3306/testhibernate
</property>
<property name="dialect">
  org.hibernate.dialect.MySQLDialect
</property>
<property name="connection.password">123456</property>
<property name="connection.driver_class">
  org.gjt.mm.mysql.Driver
</property>
<property name="show_sql">true</property>
<mapping resource="example/Cat.hbm.xml" />

</session-factory>

</hibernate-configuration>

3.测试新建包test 在其中建立测试文件TestHibernate.java
package test;

import java.util.Iterator;
import java.util.List;
import example.*;
import example.util.*;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class TestHibernate {
Session session=null;
Transaction tx=null;
public static void main(String[] args) {
TestHibernate th=new TestHibernate();
List cl=th.getAllCats();
if(cl!=null){
  Iterator it=cl.iterator();
  while(it.hasNext()){
   Cat cat=(Cat)it.next();
   System.out.println("catID:"+cat.getCatId()+"name:"+cat.getName()+"sex:"+cat.getSex());
  }
}

}
public List getAllCats(){
session=HibernateSessionFactory.getSession();
List catlist=null;
try{
  tx=session.beginTransaction();
  catlist=session.createQuery("from Cat").list();
  return catlist;
}catch(Exception ex){
  System.err.println(ex.getMessage());
  return null;
}finally{
  HibernateSessionFactory.closeSession();
}
}

}

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