使用pager-taglib.jar实现的分页技术

//1.导入pager-taglib.jar包； 

 
//2.引入pager-taglib标签：<%@ taglib prefix="pg"  uri="http://jsptags.com/tags/navigation/pager " %>  
//3.建立PagerModel类：  
public class PagerModel {  
     
    private int total;  
     
    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;  
    }  
}  
//4.pager业务逻辑部分：  
public class AbstractManager extends HibernateDaoSupport {  
    public PagerModel searchHql(String hql){  
        return searchHql(hql,null,SystemContext.getOffset(),SystemContext.getPageSize());  
    }  
    public PagerModel searchHql(String hql,Object datas){  
        return searchHql(hql,new Object[]{datas},SystemContext.getOffset(),SystemContext.getPageSize());  
    }  
    public PagerModel searchHql(String hql,Object[] datas){  
        return searchHql(hql,datas,SystemContext.getOffset(),SystemContext.getPageSize());  
    }  
    public PagerModel searchHql(String hql,int offset,int pageSize){  
        return searchHql(hql,null,offset,pageSize);  
    }  
    public PagerModel searchHql(String hql,Object datas,int offset,int pageSize){  
        return searchHql(hql,new Object[]{datas},offset,pageSize);  
    }  
    public PagerModel searchHql(String hql,Object[] datas,int offset,int pageSize){  
        String countHql = getQuery(hql);  
        Query query = getSession().createQuery(countHql);  
        if(datas !=null && datas.length > 0){  
            for(int i = 0 ; i<datas.length;i++)  
                query.setParameter(i, datas[i]);  
        }  
        int total = ((Long)query.uniqueResult()).intValue();  
        Query query1=getSession().createQuery(hql);  
        if(datas !=null && datas.length > 0){  
            for(int i = 0 ; i<datas.length;i++)  
                query1.setParameter(i, datas[i]);  
        }  
        List list =query1.setFirstResult(offset)                                            .setMaxResults(pageSize).list();  
        PagerModel pm = new PagerModel();  
        pm.setDatas(list);  
        pm.setTotal(total);  
        return pm;  
    }  
    public String getQuery(String hql){  
        int index =hql.indexOf("from");  
        if(index != -1){  
            return "select count(*)"+hql.substring(index);  
        }  
        throw new SystemException("查询语句出错！");  
    }  
}  
 
//5.定义offset、pagesize类：  
public class SystemContext {  
    private static ThreadLocal offset = new ThreadLocal();  
    private static ThreadLocal pageSize = new ThreadLocal();  
    public static int getOffset(){  
        Integer os = (Integer)offset.get();  
        if(os == null){  
            return 0;  
        }  
        return os;  
    }  
    public static void setOffset(int offsetvalue){  
        offset.set(offsetvalue);  
    }  
    public static void removeOffset(){  
        offset.remove();  
    }  
    public static int getPageSize(){  
        Integer ps = (Integer)pageSize.get();  
        if(ps == null){  
            return Integer.MAX_VALUE;  
        }  
        return ps;  
    }  
    public static void setPageSize(int pageSizevalue){  
        pageSize.set(pageSizevalue);  
    }  
    public static void removePageSize(){  
        pageSize.remove();  
    }  
}  
//6.过滤器中初始化pagesize、offset：  
public class PagerFilter implements Filter {  
    public void destroy() {  
    }  
    public void doFilter(ServletRequest request, ServletResponse response,  
            FilterChain chain) throws IOException, ServletException {  
        HttpServletRequest httpRequest =(HttpServletRequest)request;  
        SystemContext.setOffset(getOffset(httpRequest));  
        SystemContext.setPageSize(getPageSize(httpRequest));  
        try{  
            chain.doFilter(request, response);  
        }finally{  
            //清空ThreadLocal中的值  
            SystemContext.removeOffset();  
            SystemContext.removePageSize();  
        }             
    }  
    public void init(FilterConfig arg0) throws ServletException {  
    }  
    public int getOffset(HttpServletRequest request){  
        int offset = 0;  
        try {  
            offset = Integer.parseInt(request.getParameter("pager.offset"));  
        } catch (NumberFormatException ignore) {  
        }  
        return offset;  
    }     
        //设置每页显示多少条记录  
    public int getPageSize(HttpServletRequest request){  
        return 3;  
    }  
}  
//7.配置过滤器web.xml中：  
<filter>  
    <filter-name>pager-taglib</filter-name>  
    <filter-class>com.oa.util.filter.PagerFilter</filter-class>  
</filter>  
 
<filter-mapping>  
    <filter-name>pager-taglib</filter-name>  
    <url-pattern>/*</url-pattern>  
</filter-mapping>  
//8.显示效果：  
<pg:pager url="org.do" items="${pm.total }" export="currentPageNumber=pageNumber">  
    <pg:param name="parentId"/>  
    <pg:first>  
        <a href="${pageUrl}" mce_href="${pageUrl}">首页</a>  
    </pg:first>  
    <pg:prev>  
        <a href="${pageUrl }" mce_href="${pageUrl }">前页</a>  
    </pg:prev>  
    <pg:pages>  
        <c:choose>  
            <c:when test="${currentPageNumber eq pageNumber }">  
            <font color="red">${pageNumber }</font>  
            </c:when>  
            <c:otherwise>  
                <a href="${pageUrl }" mce_href="${pageUrl }">${pageNumber }</a>  
            </c:otherwise>  
        </c:choose>  
    </pg:pages>  
    <pg:next>  
        <a href="${pageUrl }" mce_href="${pageUrl }">后页</a>  
    </pg:next>  
    <pg:last>  
        <a href="${pageUrl }" mce_href="${pageUrl }">尾页</a>  
    </pg:last>  
</pg:pager>