Pager-taglib.jar(分页组件)

这个是我个人对分页的解决方案，其实就是在数据库底层做了分页查询
这套解决方案，是按照MVC的模式来做的，基于STRUTS框架。分为三个部分，表现层用的是JSP，其中用了JSTL和pager taglib做分页；控制层就是用的很传统的Action；底层就用的是Spring+Hibernate。下面分三个部分慢慢说：

说到分页：
1  首先新建一个PageModel类

package com.dengmin.oa.utils;

import java.util.List;

public class PageModel {

    /**
     * 总记录数
     */
    private int total;
    /**
     * 当前页的记录集
     */
    private List datas;

    public List getDatas() {
        return datas;
    }

    public void setDatas(List datas) {
        this.datas = datas;
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }
}

package com.dengmin.oa.utils;

import java.util.List;

public class PageModel {

    /**
     * 总记录数
     */
    private int total;
    /**
     * 当前页的记录集
     */
    private List datas;

    public List getDatas() {
        return datas;
    }

    public void setDatas(List datas) {
        this.datas = datas;
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }
}

package com.dengmin.oa.utils;

import java.util.List;

public class PageModel {

	/**
	 * 总记录数
	 */
	private int total;
	/**
	 * 当前页的记录集
	 */
	private List datas;

	public List getDatas() {
		return datas;
	}

	public void setDatas(List datas) {
		this.datas = datas;
	}

	public int getTotal() {
		return total;
	}

	public void setTotal(int total) {
		this.total = total;
	}
}

2  底层是基于Spring+Hibernate来做的。在DAO这一层，为其增加两个方法，底层的分页查询用的是Hibernate提供的分页查询。

public interface UserDao {

    public void addUser(User user);

    /**
     *
     * @param offset  从第几条记录开始查询
     * @param pagesize  每页显示多少条记录
     * @return
     */
    public PageModel findAllUser(int offset, int pagesize);
}

public interface UserDao {

    public void addUser(User user);

    /**
     *
     * @param offset  从第几条记录开始查询
     * @param pagesize  每页显示多少条记录
     * @return
     */
    public PageModel findAllUser(int offset, int pagesize);
}

public interface UserDao {

	public void addUser(User user);

	/**
	 * 
	 * @param offset  从第几条记录开始查询
	 * @param pagesize  每页显示多少条记录
	 * @return
	 */
	public PageModel findAllUser(int offset, int pagesize);
}

3  UserDao的实现类

public class UserDaoImpl extends HibernateDaoSupport implements UserDao {

    public void addUser(User user) {
        this.getHibernateTemplate().save(user);
    }

    public PageModel findAllUser(int offset, int pagesize) {

        //得到总记录数
        String queryCountHql = "select count(*) from User";

        Query query = getSession().createQuery(queryCountHql);
        int total = ((Long)query.uniqueResult()).intValue();

        List datas = getSession().createQuery("from User")
                    .setFirstResult(offset)
                    .setMaxResults(pagesize)
                    .list();
        //得到结果集
        PageModel pm = new PageModel();
        pm.setTotal(total);
        pm.setDatas(datas);

        return pm;
    }

}

public class UserDaoImpl extends HibernateDaoSupport implements UserDao {

    public void addUser(User user) {
        this.getHibernateTemplate().save(user);
    }

    public PageModel findAllUser(int offset, int pagesize) {

        //得到总记录数
        String queryCountHql = "select count(*) from User";

        Query query = getSession().createQuery(queryCountHql);
        int total = ((Long)query.uniqueResult()).intValue();

        List datas = getSession().createQuery("from User")
                    .setFirstResult(offset)
                    .setMaxResults(pagesize)
                    .list();
        //得到结果集
        PageModel pm = new PageModel();
        pm.setTotal(total);
        pm.setDatas(datas);

        return pm;
    }

}

public class UserDaoImpl extends HibernateDaoSupport implements UserDao {

	public void addUser(User user) {
		this.getHibernateTemplate().save(user);
	}
	
	public PageModel findAllUser(int offset, int pagesize) {
		
		//得到总记录数
		String queryCountHql = "select count(*) from User";
		
		Query query = getSession().createQuery(queryCountHql);
		int total = ((Long)query.uniqueResult()).intValue();
		
		List datas = getSession().createQuery("from User")
					.setFirstResult(offset)
					.setMaxResults(pagesize)
					.list();
		//得到结果集
		PageModel pm = new PageModel();
		pm.setTotal(total);
		pm.setDatas(datas);
		
		return pm;
	}

}

ok!底层的实现工作就做好了

在控制层中UserAction从DispatchAction继承重写它的unspecified方法
通过spring注入UserDao 代码如下：

public class UserAction extends DispatchAction {

    private UserDao userDao;
    @Override
    protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws Exception {

        int offset = 0;

        try {
            offset = Integer.parseInt(request.getParameter("pager.offset"));
        } catch (Exception e) {
        }
        //这里我按照每页显示10条
        PageModel pm = userDao.findAllUser(offset, 10);
        request.setAttribute("pm", pm);

        return mapping.findForward("success");
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

}

public class UserAction extends DispatchAction {

    private UserDao userDao;
    @Override
    protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws Exception {

        int offset = 0;

        try {
            offset = Integer.parseInt(request.getParameter("pager.offset"));
        } catch (Exception e) {
        }
        //这里我按照每页显示10条
        PageModel pm = userDao.findAllUser(offset, 10);
        request.setAttribute("pm", pm);

        return mapping.findForward("success");
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

}

public class UserAction extends DispatchAction {

	private UserDao userDao;
	@Override
	protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) throws Exception {
		
		int offset = 0; 
		
		try {
			offset = Integer.parseInt(request.getParameter("pager.offset"));
		} catch (Exception e) {
		}
		//这里我按照每页显示10条
		PageModel pm = userDao.findAllUser(offset, 10);
		request.setAttribute("pm", pm);
		
		return mapping.findForward("success");
	}
	
	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}
	
}

spring中的配置如下

<!-- 配置sessionFactory -->
    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="configLocation">
            <value>classpath:hibernate.cfg.xml</value>
        </property>
    </bean>
    <!-- 配置事务管理器 -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref bean="sessionFactory" />
        </property>
    </bean>

    <!-- 配置事务的传播特性 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*" propagation="REQUIRED" />
        </tx:attributes>
    </tx:advice>


<bean id="userDao" class="com.dengmin.pager.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <bean name="/userManager"
        class="com.dengmin.pager.actions.UserAction" scope="prototype">
        <property name="userDao" ref="userDao" />
    </bean>

<!-- 配置sessionFactory -->
    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="configLocation">
            <value>classpath:hibernate.cfg.xml</value>
        </property>
    </bean>
    <!-- 配置事务管理器 -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref bean="sessionFactory" />
        </property>
    </bean>

    <!-- 配置事务的传播特性 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*" propagation="REQUIRED" />
        </tx:attributes>
    </tx:advice>


<bean id="userDao" class="com.dengmin.pager.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <bean name="/userManager"
        class="com.dengmin.pager.actions.UserAction" scope="prototype">
        <property name="userDao" ref="userDao" />
    </bean>

<!-- 配置sessionFactory -->
	<bean id="sessionFactory"
		class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
		<property name="configLocation">
			<value>classpath:hibernate.cfg.xml</value>
		</property>
	</bean>
	<!-- 配置事务管理器 -->
	<bean id="transactionManager"
		class="org.springframework.orm.hibernate3.HibernateTransactionManager">
		<property name="sessionFactory">
			<ref bean="sessionFactory" />
		</property>
	</bean>

	<!-- 配置事务的传播特性 -->
	<tx:advice id="txAdvice" transaction-manager="transactionManager">
		<tx:attributes>
			<tx:method name="*" propagation="REQUIRED" />
		</tx:attributes>
	</tx:advice>


<bean id="userDao" class="com.dengmin.pager.dao.UserDaoImpl">
		<property name="sessionFactory" ref="sessionFactory" />
	</bean>

	<bean name="/userManager"
		class="com.dengmin.pager.actions.UserAction" scope="prototype">
		<property name="userDao" ref="userDao" />
	</bean>

最后是jsp页面做数据显示
这里采用了jstl和pager-taglib的标签库
首先将其引入：

<%@ taglib prefix="c"  uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="pg" uri="http://jsptags.com/tags/navigation/pager" %>

<%@ taglib prefix="c"  uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="pg" uri="http://jsptags.com/tags/navigation/pager" %>

<%@ taglib prefix="c"  uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="pg" uri="http://jsptags.com/tags/navigation/pager" %>

 

  <body>
    <h1>User Manager</h1>
    <hr/>

    <table width="778" border="0" cellPadding="0" cellSpacing="1" bgcolor="#6386d6">
    <tr bgcolor="#EFF3F7">
        <TD align="center">ID</TD>
        <TD align="center">名称</TD>
        <TD align="center">密码</TD>
        <TD align="center">地址</TD>
        <TD align="center">创建时间</TD>
        <TD align="center">相关操作</TD>

    </tr>
    <c:if test="${!empty pm.datas}">
        <c:forEach items="${pm.datas}" var="user">
            <tr bgcolor="#EFF3F7">
                <td align="center">${user.id }</td>
                <td align="center">${user.username }</td>
                <td align="center">${user.password}</td>
                <td align="center">${user.address}</td>
                <td align="center">${user.createTime }</td>
                <td align="center">
                    修改
                    &nbsp;
                    删除</td>
            </tr>
        </c:forEach>
        </c:if>
         <c:if test="${empty pm.datas}">
        <tr>
            <td colspan="5" align="center" bgcolor="#EFF3F7">
            没有找到相应的记录
            </td>
        </tr>
        </c:if>
    </table>
    <pg:pager url="userManager.do" items="${pm.total}" export="currentPageNumber=pageNumber">
    <pg:first>
        <a href="${pageUrl}">首页</a>
    </pg:first>
    <pg:prev>
        <a href="${pageUrl }">上一页</a>
    </pg:prev>
    <pg:pages>
        <c:choose>
            <c:when test="${currentPageNumber eq pageNumber}">
                <font color="red">${pageNumber }</font>
            </c:when>
            <c:otherwise>
                <a href="${pageUrl }">${pageNumber }</a>
            </c:otherwise>
        </c:choose>
    </pg:pages>
    <pg:next>
        <a href="${pageUrl }">下一页</a>
    </pg:next>
    <pg:last>
        <a href="${pageUrl }">尾页</a>
    </pg:last>
</pg:pager>
  </body>

  

  


  
    
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    linsongbin1
    2010-04-25  
    
    
  
  尚学堂的代码