hibernate分页查询的实现
1331601238 卢久贵
在mysql中新建数据好USER表,字段有3个,分别是id、username、password,贴上脚本仅供参考
create table `ding`.`user`(
`id` int default '' not null,
`username` varchar(30),
`password` varchar(30),
primary key (`id`)
);
切换到数据库透视图,新建一个mysql连接(这里就不再多说了)。
新建一个web工程,然后右键选择myeclipse,选择add hibernate........ ,把hibernate的jar加入到工程中,选择的时候注意jar包要放在lib中,可以检查下,其中有一下会选择刚新建的mysql连接,加完以后就会看到SRC下多了一个hibernate.cfg.xml文件,内容包含了配置的连接信息,如下:
<?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>
<property name="connection.username">root</property>
<property name="connection.url">
jdbc:mysql://localhost:3306/ding
</property>
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="myeclipse.connection.profile">mysql</property>
<property name="connection.password">ding</property>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
</session-factory>
</hibernate-configuration>
切换到数据库透视图,启动那个连接找到建的USER表,右键选择Hibernate Reverse Engineering...,在弹出的框里面点击 Java src folder 一行最右侧的 Browser.. 按钮来选择源码目录,这里我选择自己工程src 目录,并把下面的 Java package 右侧的输入框中输入自己想要的包名,我这里是test,接着选中下面的复选框,我选前面两个:
[x] Hibernate mapping file (*.hbm.xml) for each database table
[x] Java Data Object (POJO <> DB Table)
第2项下面的复选create abstract class我这里不选,点击next,再在ID generator选择increment(自增长),点完成。
返回j2ee透视图,会看到在test包下生成了User.java和User.hbm.xml文件,如下:
private Integer id;
private String username;
private String password;
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return this.username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return this.password;
}
public void setPassword(String password) {
this.password = password;
}
}
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="test.User" table="user">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="increment" />
</id>
<property name="username" type="java.lang.String">
<column name="username" length="30" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="30" />
</property>
</class>
</hibernate-mapping>
同时在原先的hibernate.cfg.xml中加入了 <mapping resource="test/User.hbm.xml" />,最终的hibernate.cfg.xml文件如下:
<!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>
<property name="connection.username">root</property>
<property name="connection.url">
jdbc:mysql://localhost:3306/ding
</property>
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="myeclipse.connection.profile">mysql</property>
<property name="connection.password">ding</property>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<mapping resource="test/User.hbm.xml" />
</session-factory>
</hibernate-configuration>
/**
* @Description 方法实现功能描述
* @param args
* void
* @throws 抛出异常说明
*/
public static void main(String[] args) {
SessionFactory sf = new Configuration().configure().buildSessionFactory();
Session session = sf.openSession();
String hql = "from User";
int curpage = 1;//当前页
int pagesize = 2;//每页显示数
//以上两项有一项为0则查出所有记录
List list = findOnePage(session, hql, curpage, pagesize);
for(Iterator i = list.iterator();i.hasNext();){
User user = (User) i.next();
System.out.println("username==="+user.getUsername());
}
}
public static List findOnePage(Session session,String strHQL, int offset, int pagesize){
List lst = null;
try {
Query query = session.createQuery(strHQL);
if (offset != 0 && pagesize != 0) {
query.setFirstResult((offset - 1) * pagesize);
query.setMaxResults(pagesize);
}
lst = query.list();
} catch (Exception ex) {
ex.printStackTrace();
}
return lst;
}
}
测试下就可以看到效果了
int curpage = 1;//当前页
int pagesize = 2;//每页显示数
可以改这两个参数试试