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2. 实例代码

新建一个java工程，假设取名为HibernateHelloWorld。在src下新那一个package，可取名为com.sun.hibernate.model

2.1 类代码

新建一个简单的类，放在com.sun.hibernate.model包下。内容如下：

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package com.sun.hibernate.model;   public class Student {     private int id;     private String name;     private int age;       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;     }   }

2.2 配置hibernate配置文件

hibernate\projec\etc中的hiberante.cfg.xml可以作为hibernate的配置文档，或者可使用hibernate\documentation\manual\en-US\html_single\index.html作为模板。在src文件夹下新建一个文件，并命名为hibernate.cfg.xml。（不可命名为其他文件名）最基础的配置文件可参考如下：

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<?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://localhost/hibernate</property>     <property name="connection.username">root</property>     <property name="connection.password">root</property>               <!-- JDBC connection pool (use the built-in) -->     <!-- <property name="connection.pool_size">1</property> -->               <!-- SQL dialect -->     <property name="dialect">org.hibernate.dialect.MySQLDialect</property>               <!-- Echo all executed SQL to stdout -->     <property name="show_sql">true</property>               <!-- Enable Hibernate's automatic session context management -->     <!--<property name="current_session_context_class">thread</property>-->               <!-- Drop and re-create the database schema on startup -->     <!-- <property name="hbm2ddl.auto">create</property> -->               <!-- Disable the second-level cache -->     <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>           <mapping resource="com/sun/hibernate/model/Student.hbm.xml"/>               </session-factory> </hibernate-configuration>

mapping resource处的值可根据包名和类名做修改。若类名为Student，则此处的类配置文件必为：Student.hbm.xml。

2.3 类mapping文件

新建一个文件，命名为Student.hbm.xml，放在com.sun.hibernate.model包下。内容如下：

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<?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 package="com.sun.hibernate.model">     <class name="Student">         <id name="id"></id>         <property name="name"></property>         <property name="age"></property>     </class> </hibernate-mapping>

注意文件开始处的配置，此处与hibernate.cfg.xml不一样。如果配置的与hiberante.cfg.xml一样，运行时会提示错误：“文档根元素 "hibernate-mapping" 必须匹配 DOCTYPE 根 "hibernate-configuration"  ”

2.4 StudentTest测试类

新增Student.java的junit测试类StudentTest.java，放在com.sun.hibernate.model包下代码如下：

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package com.sun.hibernate.model;   import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration;   public class StudentTest {       public static void main(String[] args){         Student s = new Student();         s.setId(1);         s.setName("s1");         s.setAge(1);                   Configuration cfg = new Configuration();         SessionFactory sf = cfg.configure().buildSessionFactory();                   Session session = sf.openSession();         session.beginTransaction();         session.save(s);         session.getTransaction().commit();         session.close();         sf.close();         } }

2.5. 运行结果

运行StudentTest.java这个类，虽然提示输入成功。去数据库查询后，可发现数据已存储到student数据表中。虽然myeclipse会提示buildSessionFactory()这个函数被deprecated，但实际上程序还是可以运行成功的。