hibernate分页查询的实现

客官°小女子只卖身不卖艺 2022-03-31 09:58 320阅读 0赞

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">  
  
  
<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：

class  User implements java.io.Serializable \{  
  
private Integer id;  
  
private String username;  
  
private String password;  
  
  
public Integer getId() \{  
returnthis.id;  
\}  
  
publicvoid setId(Integer id) \{  
this.id = id;  
\}  
  
public String getUsername() \{  
returnthis.username;  
\}  
  
publicvoid setUsername(String username) \{  
this.username = username;  
\}  
  
public String getPassword() \{  
returnthis.password;  
\}  
  
publicvoid 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">  
  
<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">  
  
  
<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

class  Test \{  
  
/\*\*  
\* @Description 方法实现功能描述  
\* @param args  
\* void  
\* @throws 抛出异常说明  
\*/  
publicstaticvoid 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());  
\}  
\}  
  
publicstatic 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