从今天起开始学习hibernate3

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2009-08 ( 3)
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Hibernate log4j Java HSQLDB JDBC

从今天开始，要学学Hibernate。
先学习hibernate3的官方文档，e文太滥了，看的很费时。
按照Tutorial一步一步来：
一、建立以下目录结构及文件：

-d:\projects
          |-lib
               |-jdbc
                   |-hsql.jar
               |-hibernate3
                         |-antlr.jar
                         |-asm.jar
                         |-asm-attrs.jar
                         |-cglib.jar
                         |-commons-collections.jar
                         |-commons-logging.jar
                         |-dom4j.jar
                         |-ehcache.jar
                         |-hibernate3.jar
                         |-jta.jar
                         |-log4j.jar
          |-hibernate3
                 |-tutorial
                         |-src
                            |-org
                               |-hibernate
                                  |-tutorial
                                       |-domain
                                            |-Event.java
                                            |-Event.hbm.xml
                                       |-util
                                            |-HibernateUtil.java

                                       |-EventManager.java
                            |-hibernate.cfg.xml
                            |-log4j.properties
                         |-build.xml
                         |-bin
          |-hsql_database
                  |-start.bat
                  |-manager.bat

二、各文件内容及说明：

1、start.bat是启动hsql数据库的批处理文件，内容：

java -cp ../lib/jdbc/hsql.jar org.hsqldb.Server -database.0 tutorial -dbname.0  tutorial

用服务器模式启动hsql数据库
2、manager.bat是启动hsql数据库图形管理界面的处理文件，内容：

java -cp ..\lib\jdbc\hsql.jar org.hsqldb.util.DatabaseManager -url jdbc:hsqldb:hsql://localhost/tutorial

3、build.xml内容：

<project name="hibernate-tutorial" default="compile">

    <property name="sourcedir" value="${basedir}/src"/>
    <property name="targetdir" value="${basedir}/bin"/>
    <property name="librarydir" value="${basedir}/../../lib/hibernate"/>

    <path id="libraries">
        <fileset dir="${librarydir}">
            <include name="*.jar"/>
        </fileset>
	<fileset dir="${librarydir}/../jdbc">
            <include name="*.jar"/>
        </fileset>
    </path>

    <target name="clean">
        <delete dir="${targetdir}"/>
        <mkdir dir="${targetdir}"/>
    </target>

    <target name="compile" depends="clean, copy-resources">
      <javac srcdir="${sourcedir}"
             destdir="${targetdir}"
             classpathref="libraries"/>
    </target>

    <target name="copy-resources">
        <copy todir="${targetdir}">
            <fileset dir="${sourcedir}">
                <exclude name="**/*.java"/>
            </fileset>
        </copy>
    </target>

    <target name="run" depends="compile">
    	<java fork="true" classname="org.hibernate.tutorial.EventManager" classpathref="libraries">
      	  <classpath path="${targetdir}"/>
     	   <arg value="${action}"/>
    	</java>
    </target>
</project>

dos命令行下输入“ant” 将编译程序，输入“ant run -Daction=store”将持久类Event的对象写入数据库中，输入“ant run -Daction=list”将显示存储在数据库中的被持久化的Event类对象。（当然前提是当前目录在d:\projects\hibernate3下）

4、log4j.properties内容：

og4j.rootLogger=DEBUG, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

引用

Hibernate uses commons logging and provides two choices: Log4j and JDK 1.4 logging. Most developers prefer Log4j

hibernate采用commons logging并提供两种选择，Log4j 和 JDK 1.4 logging，多数开发者倾向于Log4j，如果是Log4j就要在类路径下配置log4j.properties（或者通过-Dlog4j.configuration=xx.properties来指定），如果是JDK 1.4 logging就要配置：logging.properties 并通过-Djava.util.logging.config.file=D:\your\path\to\logging.properties来指定。具体的设置参考http://www.blogjava.net/tedeyang/articles/18935.html
5、hibernate.cfg.xml内容：

<?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>

        <!-- Database connection settings -->
        <property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
        <property name="connection.url">jdbc:hsqldb:hsql://localhost/tutorial</property>
        <property name="connection.username">sa</property>
        <property name="connection.password"></property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.HSQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>

        <mapping resource="org/hibernate/tutorial/domain/Event.hbm.xml"/>

    </session-factory>
</hibernate-configuration>

6、Event.java

package org.hibernate.tutorial.domain;

import java.util.Date;

public class Event {
    private Long id;

    private String title;
    private Date date;
   /*The no-argument constructor is a requirement for all persistent classes; 
   The constructor can be private, however package or public visibility is    required for runtime proxy generation and efficient data retrieval without bytecode instrumentation. */
    public Event() {}

    public Long getId() {
        return id;
    }
   //由于id通常由hibernate产生，故id的setter方法一般用private来限制。
   //

    private void setId(Long id) {
        this.id = id;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

7、Event.hbm.xml

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

<hibernate-mapping package="org.hibernate.tutorial.domain">
	<class name="Event" table="EVENTS">
		<id name="id" column="EVENT_ID">
			<generator class="native" />
		</id>
		<property name="date" type="timestamp" column="EVENT_DATE" />
		<property name="title" />
	</class>
</hibernate-mapping>

引用

Hibernate by default uses the property name as the column name. This works for title, however, date is a reserved keyword in most databases so you will need to map it to a different name. Hibernate cannot know if the property, which is of java.util.Date, should map to a SQL date, timestamp, or time column. Full date and time information is preserved by mapping the property with a timestamp converter.

Hibernate 默认的把属性名作为列名，但是，date在大多数的数据库管理系统中是保留关键字，所以的映射一个其他的名字，当一个属性类型为java.util.Date时，hibernate不知道该如何映射到SQL类型的date, timestamp, or time，但是timestamp类型完全包含了date 和 time 的所有信息，所以可以将java.util.Date映射为timestamp

8、HibernateUtil.java

package org.hibernate.tutorial.util;

import org.hibernate.*;
import org.hibernate.cfg.*;

public class HibernateUtil {

    private static final SessionFactory sessionFactory;

    static {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            sessionFactory = new Configuration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

}

9、EventManager.java

package org.hibernate.tutorial;

import org.hibernate.Session;

import java.util.*;

import org.hibernate.tutorial.domain.Event;
import org.hibernate.tutorial.util.HibernateUtil;

public class EventManager {

    public static void main(String[] args) {
        EventManager mgr = new EventManager();

        if (args[0].equals("store")) {
            mgr.createAndStoreEvent("My Event", new Date());
        }else if (args[0].equals("list")) {
            List events = mgr.listEvents();
            for (int i = 0; i < events.size(); i++) {
                Event theEvent = (Event) events.get(i);
                System.out.println(
                        "Event: " + theEvent.getTitle() + " Time: " + theEvent.getDate()
                );
            }
	 }
        HibernateUtil.getSessionFactory().close();
    }

    private void createAndStoreEvent(String title, Date theDate) {
        Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();

        Event theEvent = new Event();
        theEvent.setTitle(title);
        theEvent.setDate(theDate);
        session.save(theEvent);

        session.getTransaction().commit();
    }
    private List listEvents() {
        Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();
        List result = session.createQuery("from Event").list();
        session.getTransaction().commit();
        return result;
   }

}