本文实例讲述了基于hibernate实现的分页技术。分享给大家供大家参考,具体如下:
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
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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();
}
});
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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:
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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;
}
}
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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
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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 ;
}
}
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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。
希望本文所述对大家基于Hibernate框架的Java程序设计有所帮助。