pager-taglib的分页技术

pager-taglib+struts2分页

//1.导入pager-taglib.jar包；  
//2.引入pager-taglib标签：<%@ taglib prefix="pg& quot;  uri="http://jsptags.com/tags/navigation/pager" %>  
//3.建立PagerModel类：  
public class PagerModel {  
    /** 
     * 总记

//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 { 
    /**
     * 总记录数
     */
    private int total; 
    /**
     * 当前页结果集
     */
    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; 
    } 
} 
//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>