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` 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：

public class User implements java.io.Serializable {

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;
}

}

<? 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 " />
< 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：

<? 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;
}

}