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。