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SSH2实现数据库和界面的分页

分页应该是在我们开发web应用时经常要做的工作，能够比较简洁的实现数据库和视图层的分页十分重要。

在数据库层利用Hibernate进行数据库的分页，将从数据库中查询出的数据封装为javabean；在视图层就可以方便的实现分页。

创建PageBean

package com.fishing.common.bean;  
 
import java.util.List;  
@SuppressWarnings("unchecked")  
public class PageBean {  
      
    private List list; // 要返回的某一页的记录列表  
 
    private int allRow; // 总记录数  
    private int totalPage; // 总页数  
    private int currentPage; // 当前页  
    private int pageSize; // 每页记录数  
 
      
    private boolean isFirstPage; // 是否为第一页  
    private boolean isLastPage; // 是否为最后一页  
    private boolean hasPreviousPage; // 是否有前一页  
    private boolean hasNextPage; // 是否有下一页  
 
    public List getList() {  
        return list;  
    }  
 
    public void setList(List list) {  
        this.list = list;  
    }  
 
    public int getAllRow() {  
        return allRow;  
    }  
 
    public void setAllRow(int allRow) {  
        this.allRow = allRow;  
    }  
 
    public int getTotalPage() {  
        return totalPage;  
    }  
 
    public void setTotalPage(int totalPage) {  
        this.totalPage = totalPage;  
    }  
 
    public int getCurrentPage() {  
        return currentPage;  
    }  
 
    public void setCurrentPage(int currentPage) {  
        this.currentPage = currentPage;  
    }  
 
    public int getPageSize() {  
        return pageSize;  
    }  
 
    public void setPageSize(int pageSize) {  
        this.pageSize = pageSize;  
    }  
 
    /** */ 
    /**  
     * 初始化分页信息  
     */ 
    public void init() {  
        this.isFirstPage = isFirstPage();  
        this.isLastPage = isLastPage();  
        this.hasPreviousPage = isHasPreviousPage();  
        this.hasNextPage = isHasNextPage();  
    }  
 
    /** */ 
    /**  
     * 以下判断页的信息,只需getter方法(is方法)即可  
     *   
     * @return  
     */ 
 
    public boolean isFirstPage() {      
        return (currentPage == 1);// 如是当前页是第1页      
    }     
    public boolean isLastPage() {      
 return currentPage == totalPage; //如果当前页是最后一页      
}     
    public boolean isHasPreviousPage() {      
 return currentPage != 1; //只要当前页不是第1页      
}     
    public boolean isHasNextPage() {      
 return currentPage != totalPage; //只要当前页不是最后1页      
}     
    /** */ 
    /**  
     * 计算总页数,静态方法,供外部直接通过类名调用  
     *   
     * @param pageSize  
     *            每页记录数  
     * @param allRow  
     *            总记录数  
     * @return 总页数  
     */ 
    public static int countTotalPage(final int pageSize, final int allRow) {  
        int totalPage = allRow % pageSize == 0 ? allRow / pageSize : allRow  
                / pageSize + 1;  
        return totalPage;  
    }  
 
    /** */ 
    /**  
     * 计算当前页开始记录  
     *   
     * @param pageSize  
     *            每页记录数  
     * @param currentPage  
     *            当前第几页  
     * @return 当前页开始记录号  
     */ 
    public static int countOffset(final int pageSize, final int currentPage) {  
        final int offset = pageSize * (currentPage - 1);  
        return offset;  
    }  
 
    /** */ 
    /**  
     * 计算当前页,若为0或者请求的URL中没有"?page=",则用1代替  
     *   
     * @param page  
     *            传入的参数(可能为空,即0,则返回1)  
     * @return 当前页  
     */ 
    public static int countCurrentPage(int page) {  
        final int curPage = (page == 0 ? 1 : page);  
        return curPage;  
    }  
}

在Dao的抽象接口BaseDao中添加方法

public List queryForPage(final String hql, final int offset,  
            final int length);

在Dao的实现类JianSheDWDaoImpl中实现方法

public List queryForPage(final String hql, final int offset,  
            final int length) {  
        List list = getHibernateTemplate().executeFind(new HibernateCallback() {  
 
            public Object doInHibernate(Session session)  
                    throws HibernateException, SQLException {  
                Query query = session.createQuery(hql);  
                query.setFirstResult(offset);  
                query.setMaxResults(length);  
                List list = query.list();  
                return list;  
 
            }  
        });  
 
        return list;  
    }

在service抽象层接口JianSheDWService中添加方法

public PageBean queryForPage(int pageSize,int currentPage);

在service实现类中实现方法

public PageBean queryForPage(int pageSize, int page) {  
        final String hql = "from JianSheDWBean"; // 查询语句  
        int allRow = this.baseDao.getAllRowCount(hql); // 总记录数  
        int totalPage = PageBean.countTotalPage(pageSize, allRow); // 总页数  
        final int offset = PageBean.countOffset(pageSize, page); // 当前页开始记录  
        final int length = pageSize; // 每页记录数  
        final int currentPage = PageBean.countCurrentPage(page);  
        List<JianSheDWBean> list = this.baseDao.queryForPage(hql, offset, length); // "一页"的记录  
 
        // 把分页信息保存到Bean中  
        PageBean pageBean = new PageBean();  
        pageBean.setPageSize(pageSize);  
        pageBean.setCurrentPage(currentPage);  
        pageBean.setAllRow(allRow);  
        pageBean.setTotalPage(totalPage);  
        pageBean.setList(list);  
        pageBean.init();  
        return pageBean;  
 
    }

在视图层action中建立分页模型

package com.fishing.action.lcq;  
 
 
 
import com.fishing.common.bean.JianSheDWBean;  
import com.fishing.common.bean.PageBean;  
import com.fishing.service.lcq.JianSheDWService;  
import com.opensymphony.xwork2.ActionSupport;  
 
@SuppressWarnings("serial")  
public class GetInfoJSDWListAction extends ActionSupport {  
 
    private int page; // 第几页  
 
    private PageBean pageBean; // 包含分布信息的bean  
 
    private JianSheDWBean jianSheDWBean;  
    // private PageBean page;  
    private JianSheDWService jianSheDWService;  
 
    public int getPage() {  
        return page;  
    }  
 
    public void setPage(int page) {  
        this.page = page;  
    }  
 
    public PageBean getPageBean() {  
        return pageBean;  
    }  
 
    public void setPageBean(PageBean pageBean) {  
        this.pageBean = pageBean;  
    }  
 
    public JianSheDWBean getJianSheDWBean() {  
        return jianSheDWBean;  
    }  
 
    public void setJianSheDWBean(JianSheDWBean jianSheDWBean) {  
        this.jianSheDWBean = jianSheDWBean;  
    }  
 
    public JianSheDWService getJianSheDWService() {  
        return jianSheDWService;  
    }  
 
    public void setJianSheDWService(JianSheDWService jianSheDWService) {  
        this.jianSheDWService = jianSheDWService;  
    }  
 
    @Override     
     public String execute() throws Exception {      
          
     //分页的pageBean,参数pageSize表示每页显示记录数,page为当前页      
     this.pageBean = jianSheDWService.queryForPage(10, page);      
     return SUCCESS;  
    }  
}

在jsp中编写分页

<tr class="odd"> 
                                                    <td> 
                                                        &nbsp;  
                                                    </td> 
                                                    <td> 
                                                        <s:if test="%{pageBean.currentPage == 1}">     
                                          首页      上一页  
                                            </s:if> 
                                                        <s:else> 
                                                            <a href="jianguan/getJSDWInfos.action?page=1">首页</a> 
                                                            <a 
                                                                href="jianguan/getJSDWInfos.action?page=<s:property value="%{pageBean.currentPage-1}"/>" />上一页</a> 
 
                                                        </s:else> 
                                                    </td> 
                                                    <td> 
                                                        <s:if test="%{pageBean.currentPage != pageBean.totalPage}"> 
 
                                                            <a 
                                                                href="jianguan/getJSDWInfos.action?page=<s:property value="%{pageBean.currentPage+1}"/>">下一页</a> 
                                                            <a 
                                                                href="jianguan/getJSDWInfos.action?page=<s:property value="pageBean.totalPage"/>">尾页  
                                                            </a> 
                                                        </s:if> 
                                                        <s:else>   
                                          下一页  尾页   
                                            </s:else> 
                                                    </td> 
 
                                                    <td> 
                                                        <div align="center"> 
                                                            页次  
                                                            <s:property value="pageBean.currentPage" /> 
                                                            /  
                                                            <s:property value="pageBean.totalPage" /> 
                                                            &nbsp;&nbsp;&nbsp;共  
                                                            <s:property value="pageBean.allRow" /> 
                                                            记录  
                                                        </div> 
                                                        <div align="center"></div> 
                                                    </td> 
                                                </tr>