当前位置:编程学习 > JAVA >>

Hibernate入门心得

开发阶段:

新建一个JAVA项目,目录结构如下:

 

将准备的jar包引入到项目中。

 

hibernate.cfg.xml:(Hibernate的配置文件,放在项目的src目录下):<?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">
 
     <!-- Generated by MyEclipse Hibernate Tools.                   -->
 <hibernate-configuration>
 
     <session-factory>
         <!-- 设置驱动类 -->
         <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
         <!-- 设置连接池默认个数 -->
         <property name="connection.pool_size">20</property>
         <!-- 设置JDBC URL -->
         <property name="connection.url">jdbc:mysql://localhost:3306/book</property>
         <!-- 设置数据库用户名 -->
         <property name="connection.username">username</property>
         <!-- 设置数据库用户密码 -->
         <property name="connection.password">passwrod</property>
         <!-- 设置SQL方言 -->
         <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
         <!-- 设置是否显示SQL语句 -->
         <property name="show_sql">true</property>
         <!-- 设置格式化SQL语句 -->
         <property name="format_sql">true</property>
         <property name="current_session_context_class">thread</property>
 
         <mapping resource="com/sunflower/bean/Person.hbm.xml" />
     </session-factory>
 
 </hibernate-configuration>
这里配置的是MySQL数据库的驱动和连接,在开始的时候忘了加26行,结果调试的时候出错,得不到session,关于这个标签的使用,请参考如下文章:http://blog.sina.com.cn/s/blog_5ecfe46a0100e467.html 第28行是对象关系映射文件的配置.

Person.java:(人的实体类,对应到关系数据库中的blog表)package com.sunflower.bean;

 
 import java.io.Serializable;
 
 /**
  * 博客用户的实体类
  *
  * @author hanyuan
  * @time 2012-7-8 下午11:53:23
  */
 public class Person implements Serializable {
     private Integer id;
     private String username;
     private String password;
     private String caption;
     private String content;
 
     public Integer getId() {
         return id;
     }
 
     public void setId(Integer id) {
         this.id = id;
     }
 
     public String getUsername() {
         return username;
     }
 
     public void setUsername(String username) {
         this.username = username;
     }
 
     public String getPassword() {
         return password;
     }
 
     public void setPassword(String password) {
         this.password = password;
     }
 
     public String getCaption() {
         return caption;
     }
 
     public void setCaption(String caption) {
         this.caption = caption;
     }
 
     public String getContent() {
         return content;
     }
 
     public void setContent(String content) {
         this.content = content;
     }
 
 }
 第12~16行中的属性对应到数据库中的blog表的字段,其中id是主键索引.

 

Person.hbm.xml:(对象关系映射配置文件)<?xml version="1.0"?>

 <!DOCTYPE hibernate-mapping PUBLIC
     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 
 <hibernate-mapping>
     <!-- 设置实体类与数据库中表的对应关系 -->
     <class name="com.sunflower.bean.Person" table="blog">
 
         <id name="id" type="java.lang.Integer">
             <column name="id"></column>
             <!-- 将逐渐设置为自增 -->
             <generator class="increment"></generator>
         </id>
 
         <property name="username" type="java.lang.String" not-null="true">
             <column name="username"></column>
         </property>
 
         <property name="password" type="java.lang.String">
             <column name="password"></column>
         </property>
 
         <property name="caption" typ

补充:软件开发 , Java ,
CopyRight © 2022 站长资源库 编程知识问答 zzzyk.com All Rights Reserved
部分文章来自网络,