先决条件:
1、开发工具Eclipse安装了插件Lomboz,并指明Server为JBoss
2、已经在Jboss中建立了与MySql的DataSource连接,JNDI为 java:/MySqlDS
3、已经在MySql中建立了表 CAT
Column | Type | Modifiers
--------+-----------------------+-----------
cat_id | character(32) | not null
name | character varying(16) | not null
sex | character(1) |
weight | real |
Indexes: cat_pkey primary key btree (cat_id)
整合步骤:
1、生成一个WEB应用
2、在这个应用的WEB-INF\lib下应该包含以下Hibernate必需包
hibernate2.jar
odmg-3.0.jar
commons-collections-2.1.1.jar
commons-logging-1.0.4.jar
dom4j-1.4.jar
ehcache-0.9.jar
cglib-full-2.0.2.jar
3、在这个应用的WEB-INF\classes下生成Hibernate配置文件hibernate.cfg.xml(也可以用hibernate.properties,此处不议),内容如下:
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration
PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
<session-factory name="hibernate/SessionFactory">
<property name="connection.datasource">java:/MySqlDS</property>
<property name="show_sql">true</property>
<property name="dialect">hibernate.dialect net.sf.hibernate.dialect.MySQLDialect</property>
<!-- Mapping files -->
<mapping resource="Cat.hbm.xml"/>
</session-factory>
</hibernate-configuration>
hibernate/SessionFactory为你需要绑定SessionFactory的JNDI名(绑定之后可以在容器内用Context lookup)。
java:/MySqlDS为你已经绑定好的MySql DataSource名。
hibernate.dialect net.sf.hibernate.dialect.MySQLDialect为Hibernate指明数据库方言为MYSQL。
Cat.hbm.xml为Hibernate映射文件,下面会提到。
4、定义可持久化类(POJO)-- Cat.java
public class Cat {
private String id;
private String name;
private char sex;
private float weight;
public Cat() {
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public char getSex() {
return sex;
}
public void setSex(char sex) {
this.sex = sex;
}
public float getWeight() {
return weight;
}
public void setWeight(float weight) {
this.weight = weight;
}
}
5、定义类映射文件-- Cat.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
<class name="com.pbmaster.study.hibernate.po.Cat" table="CAT">
<!-- A 32 hex character is our surrogate key. It's automatically
generated by Hibernate with the UUID pattern. -->
<id name="id" type="string" unsaved-value="null" >
<column name="CAT_ID" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>
<!-- A cat has to have a name, but it shouldn' be too long. -->
<property name="name">
<column name="NAME" sql-type="varchar(16)" not-null="true"/>
</property>
<property name="sex"/>
<property name="weight"/>
</class>
</hibernate-mapping>
此xml文件放置到hibernate.cfg.xml相同的目录(不知道放到其他地方行不行,待查)。
6、定义一个startup Servlet -InitHibernate.java,在Servlet的init()中启动Hibernate,并绑定JNDI
public class InitHibernate extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
try{
SessionFactory sf = new Configuration().configure().buildSessionFactory();
System.out.println("Hibernate Startup completed successfully");
}
catch(Exception ex){
ex.printStackTrace();
}
//TODO Method stub generated by Lomboz
}
public void service(ServletRequest request, ServletResponse response)
throws ServletException, IOException {
//TODO Method stub generated by Lomboz
}
}
为了能让这个Servlet能在服务器启动时被运行,需要配置WEB.XML文件:
<servlet>
<servlet-name>inithibernate</servlet-name>
<display-name>inithibernate</display-name>
<servlet-class>com.pbmaster.study.hibernate.servlet.InitHibernate</servlet-class>
<load-on-startup>10</load-on-startup>
</servlet>
7、OK,部署这个WEB应用,启动JBOSS!如果在JBOSS的控制台打出的信息中没有Exception信息,那么就成功。
根据Hibernate文档的介绍,也可以用另一种方式,就是定义一个HibernateUtil类,调用这个类的静态方法currentSession一次。其实这2种方法基本一样,都能达到效果。
8、测试HIBERNATE
定义一个Servlet,其service()中有如下代码:
Context ctx=new InitialContext();
sf = (SessionFactory) ctx.lookup("hibernate/SessionFactory");
Session session=sf.openSession();
Transaction tx= session.beginTransaction();
Cat princess = new Cat();
princess.setName("Princess");
princess.setSex('F');
princess.setWeight(7.4f);
session.save(princess);
tx.commit();
session.close();
如果没有异常,数据库当中应该已经有了一条数据!
再来一个jsp做查询的例子:
<!-- Copyright (c) 2002 by ObjectLearn. All Rights Reserved. -->
<%@ page import="javax.naming.*"%>
<%@ page import="net.sf.hibernate.*"%>
<%@ page import="java.util.*"%>
<%@ page import="com.catmiw.hibernate.study.po.*"%>
<%
try {
Context ctx = new InitialContext(); //得到初始化上下文
SessionFactory sf = (SessionFactory) ctx.lookup("hibernate/SessionFactory");
Session sess=sf.openSession();
String temp;
System.out.println("Success connect Hibernate!");
Query query = sess.createQuery("select cat from Cat as cat where cat.sex = :sex");
query.setCharacter("sex", 'F');
for (Iterator it = query.iterate(); it.hasNext();) {
Cat cat = (Cat) it.next();
temp = cat.getName() ;
%>
<html>
<head>
<title>Welcome</title>
</head>
<body>
<center>name is : <%=temp%></center>
</body>
</html>
<%
}
sess.close();
}
catch (Exception e) {
System.out.print("get data error!");
e.printStackTrace();
}
%>
从显示的SQL语句看,当查询一个结果集时,HIBERNATE是先把满足条件的记录的主键取出来,再一条一条按主键去取。
(看后当场昏倒,吐血......,变吐血还在边问“为什么这样.......,这样不是效率太低了吗?? ”)
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