欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

基于hibernate实现的分页技术实例分析

程序员文章站 2024-03-09 10:18:17
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...

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

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。

希望本文所述对大家基于hibernate框架的java程序设计有所帮助。