关于的Hibernate的开始
学习java得学习一个java数据库存持久层，这样对于操作数据库会有非常一效率的提升。选一个大家熟知的Hibernate吧。精通hibernate3.0那个书，指导我开始了一个Hibernate的程序的实验。
1. 环境：
jdk1.6, myeclipse, mysql, hibernate3.0及相关的包。
2. 建表：
CREATE TABLE `login` (
`id` int(11) NOT NULL auto_increment,
`name` varchar(100) default '',
`password` varchar(100) default '',
PRIMARY KEY (`id`)
) TYPE=MyISAM;
3. 文件结构
4. 导入包
5.开始的数据库
6. UserInfo类
package com.lr;
public class UserInfo {
private Integer id ;
private String userName ;
private String password ;
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;
}
}
7.UserInfo.hbm.xml文件
<?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> <!--类和表之间的关联--> <class name="com.lr.UserInfo" table="login"> <!--类对象的主键和表的主键的关联--> <id name="id" type="integer"> <column name="id" /> <!--指明主键的自增长类型--> <generator class="identity" /> </id> <!--以下为普通字段的关联--> <property name="userName" type="string"> <column name="name" length="100" /> </property> <property name="password" type="string"> <column name="password" length="100" /> </property> </class> </hibernate-mapping>
8.hibernate.cfg.xml文件
<?xml version='1.0' encoding='gb2312'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!--配置数据库驱动-->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!--配置数据库网络连接的url-->
<property name="hibernate.connection.url">jdbc:mysql://localhost/hibernate</property>
<!--配置数据库网络连接的用户名，默认一般为root-->
<property name="hibernate.connection.username">root</property>
<!--配置数据库网络连接的密码-->
<property name="hibernate.connection.password"></property>
<!--配置数据库网络连接池的大小-->
<property name="hibernate.connection.pool.size">20</property>
<!--后台是否显示sql，开发时为true，运行时为false-->
<property name="hibernate.show_sql">true</property>
<!-- 设置JDBC的隔离级别-->
<property name="hibernate.connection.isolation">2</property>
<property name="hibernate.format_sql">true</property>
<property name="jdbc.fetch_size">50</property>
<property name="jdbc.batch_size">25</property>
<property name="jdbc.use_scrollable_resultset">false</property>
<property name="connection.useUnicode">true</property>
<!--编码方式-->
<property name="connection.characterEncoding">gbk</property>
<!--数据库方言，每个数据库都有方言，hibernate已经为大多数数据库指明了方言-->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<mapping resource="com/lr/UserInfo.hbm.xml" />
<!-- mapping resource="com.lr.UserInfo.java" -->
</session-factory>
</hibernate-configuration>
9.HibernateTest.java
package com.lr;
import java.util.Iterator;
import java.util.List;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class HibernateTest {
public static void main(String[] args) {
Configuration conf = new Configuration().configure() ;
SessionFactory sessions = conf.buildSessionFactory();
Session session = sessions.openSession();
Transaction tx = null;
try {
// 开始事务
tx = session.beginTransaction();
// //给对象设定值
UserInfo u = new UserInfo();
u.setUserName("李四");
u.setPassword("123456");
System.out.println("start...");
//保存数据到数据库
session.save(u);
// 从持久化类UserInfo中读取数据
UserInfo user = (UserInfo) session.get(UserInfo.class, new Integer(1)) ;
System.out.println("UserName:"+user.getUserName());
//load前提是存在指定的数据，用get数据库中可没有指定的记录
//删除记录
String hqld = "delete UserInfo where id=9" ;
Query queryd = session.createQuery(hqld) ;
queryd.executeUpdate() ;
//使用hql语句
String hqls = "from UserInfo userInfo where userInfo.userName like ?";
Query querys = session.createQuery(hqls);
querys.setParameter(0, "l%");
List list = querys.list();
// 结束事务
tx.commit();
Iterator<?> it = list.iterator();
while (it.hasNext()) {
UserInfo userInfo = (UserInfo) it.next();
System.out.println(userInfo.getUserName());
}
System.out.println("it is successful！");
} catch (HibernateException e) {
System.out.println(e.getMessage());
//e.printStackTrace();
if (tx != null) {
tx.rollback();
}
} finally {
session.close();
}
}
}
10.结果显示
11.操作后的数库
12.可能会遇到的问题
| log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment). log4j:WARN Please initialize the log4j system properly. start... Exception in thread "main" java.lang.NoClassDefFoundError: antlr/ANTLRException at org.hibernate.hql.ast.ASTQueryTranslatorFactory.createQueryTranslator(ASTQueryTranslatorFactory.java:27) at org.hibernate.impl.SessionFactoryImpl.createQueryTranslators(SessionFactoryImpl.java:357) at org.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:423) at org.hibernate.impl.SessionImpl.getQueries(SessionImpl.java:884) at org.hibernate.impl.SessionImpl.executeUpdate(SessionImpl.java:865) at org.hibernate.impl.QueryImpl.executeUpdate(QueryImpl.java:89) at com.lr.HibernateTest.main(HibernateTest.java:41) Caused by: java.lang.ClassNotFoundException: antlr.ANTLRException at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 7 more |