基于hibernate实现的分页技术

转自：http://blog.csdn.net/beyond667/article/details/7385332

先说明一下基于hibernate实现分页的原理，假如从数据库取出100条数据，我们要让每页显示10条，假如从30开始，只需要设置起始位置和最大的返回结果即可

先上代码：注意传进来的参数有 Page这类，后面有介绍

 

public List<Article> queryByPage(final String username, final Page page) {
        return this.getHibernateTemplate().executeFind(new HibernateCallback() {
            public Object doInHibernate(Session session)
                    throws HibernateException, SQLException {
                Query query = session.createQuery("select art from Article art where art.username = ?");
                //设置参数
                query.setParameter(0, username);
                //设置每页显示多少个，设置多大结果。
                query.setMaxResults(page.getEveryPage());
                //设置起点
                query.setFirstResult(page.getBeginIndex());
                return query.list();
            }
        });

上面关键代码是 setMaxResults(),和setFirstResult(),即设置最大显示值和起点

 

这里我们需要一个Page工具类，用来操作分页。

Page.java

 

package com.fenye;

public class Page {
    // 1.每页显示数量(everyPage)
    private int everyPage;
    // 2.总记录数(totalCount)
    private int totalCount;
    // 3.总页数(totalPage)
    private int totalPage;
    // 4.当前页(currentPage)
    private int currentPage;
    // 5.起始点(beginIndex)
    private int beginIndex;
    // 6.是否有上一页(hasPrePage)
    private boolean hasPrePage;
    // 7.是否有下一页(hasNextPage)
    private boolean hasNextPage;

    public Page(int everyPage, int totalCount, int totalPage, int currentPage,
            int beginIndex, boolean hasPrePage, boolean hasNextPage) {
        this.everyPage = everyPage;
        this.totalCount = totalCount;
        this.totalPage = totalPage;
        this.currentPage = currentPage;
        this.beginIndex = beginIndex;
        this.hasPrePage = hasPrePage;
        this.hasNextPage = hasNextPage;
    }

    //构造函数，默认
    public Page(){}

    //构造方法，对所有属性进行设置


    public int getEveryPage() {
        return everyPage;
    }

    public void setEveryPage(int everyPage) {
        this.everyPage = everyPage;
    }

    public int getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }

    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 getBeginIndex() {
        return beginIndex;
    }

    public void setBeginIndex(int beginIndex) {
        this.beginIndex = beginIndex;
    }

    public boolean isHasPrePage() {
        return hasPrePage;
    }

    public void setHasPrePage(boolean hasPrePage) {
        this.hasPrePage = hasPrePage;
    }

    public boolean isHasNextPage() {
        return hasNextPage;
    }

    public void setHasNextPage(boolean hasNextPage) {
        this.hasNextPage = hasNextPage;
    }

}

Page工具类主要是封装页面信息，一共多少数据啊，一页显示多少啊，起点的序号，总页数，是否有上一页下一页，当前页。

 

还需要一个操作page的工具类，PageUtil.java

 

package com.sanqing.fenye;
/*
 * 分页信息辅助类
 */
public class PageUtil {

    public static Page createPage(int everyPage,int totalCount,int currentPage) {
        everyPage = getEveryPage(everyPage);
        currentPage = getCurrentPage(currentPage);
        int totalPage = getTotalPage(everyPage, totalCount);
        int beginIndex = getBeginIndex(everyPage, currentPage);
        boolean hasPrePage = getHasPrePage(currentPage);
        boolean hasNextPage = getHasNextPage(totalPage, currentPage);
        return new Page(everyPage, totalCount, totalPage, currentPage,
                beginIndex, hasPrePage,  hasNextPage);
    }

    public static Page createPage(Page page,int totalCount) {
        int everyPage = getEveryPage(page.getEveryPage());
        int currentPage = getCurrentPage(page.getCurrentPage());
        int totalPage = getTotalPage(everyPage, totalCount);
        int beginIndex = getBeginIndex(everyPage, currentPage);
        boolean hasPrePage = getHasPrePage(currentPage);
        boolean hasNextPage = getHasNextPage(totalPage, currentPage);
        return new Page(everyPage, totalCount, totalPage, currentPage,
                beginIndex, hasPrePage,  hasNextPage);
    }

    //设置每页显示记录数
    public static int getEveryPage(int everyPage) {
        return everyPage == 0 ? 10 : everyPage;
    }

    //设置当前页
    public static int getCurrentPage(int currentPage) {
        return currentPage == 0 ? 1 : currentPage;
    }

    //设置总页数,需要总记录数，每页显示多少
    public static int getTotalPage(int everyPage,int totalCount) {
        int totalPage = 0;
        if(totalCount % everyPage == 0) {
            totalPage = totalCount / everyPage;
        } else {
            totalPage = totalCount / everyPage + 1;
        }
        return totalPage;
    }

    //设置起始点，需要每页显示多少，当前页
    public static int getBeginIndex(int everyPage,int currentPage) {
        return (currentPage - 1) * everyPage;
    }

    //设置是否有上一页，需要当前页
    public static boolean getHasPrePage(int currentPage) {
        return currentPage == 1 ? false : true;
    }

    //设置是否有下一个，需要总页数和当前页
    public static boolean getHasNextPage(int totalPage, int currentPage) {
        return currentPage == totalPage || totalPage == 0 ? false : true;
    }

}

创建Page只需要3个参数，每页显示多少数据，当前页，总共多少数据，其他的4个参数都可以通过这三个计算出来

 

所以后面要创建Page，只需要调用这工具方法PageUtil.createPage(3个参数)，就返回一Page.

返回的Page就是前面参数的Page，即要显示的分页

这样就算完成了分页的功能。