hibernate分页查询的实现

hibernate分页查询的实现

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` intdefault '' 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：

public class Userimplements java.io.Serializable {

private Integer id;

private String username;

private String password;


public Integer getId() {
returnthis.id;
}

public void setId(Integer id) {
this.id= id;
}

public String getUsername() {
returnthis.username;
}

public void setUsername(String username) {
this.username= username;
}

public String getPassword() {
returnthis.password;
}

public void setPassword(String password) {
this.password= password;
}

}

<?xml version="1.0" encoding="utf-8"?>
<!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"/>
<generatorclass="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：

<?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>
<mapping resource="test/User.hbm.xml"/>

</session-factory>

</hibernate-configuration>

写个Test测试类

public class Test {

/**
* @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;
}

}