Hibernate分页2

这个是在之前的PagingUtil的基础上做了一些改进,只要传入一个select的sql语句,就可以对其进行分页:

package Util;

import java.util.*;

import model.*;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

/**
 * 这个是用于Hibernate分页的公共库,构造方法必须传入一个完整的sql语句
 * @author chj
 *
 */
public class PagingUtil2 {

    private static SessionFactory sf = null;
    private String sql = "";
    private int pageSize = 5;        //每页显示数据量,默认为5
    private int pageno = 1;        //当前页数,默认首页
    private int pagecount = -1;    //总页数
    private int datacount = -1;    //数量总数
    
    public PagingUtil2(String sql){
        this.sql = sql;
        if(sf == null){
            sf = HibernateUtil.getSessionFactory();
        }
        calPagecount();
    }
    
    public PagingUtil2(String sql,int pageSize){
        this.sql = sql;
        this.pageSize = pageSize;
        if(sf == null){
            sf = new AnnotationConfiguration().configure().buildSessionFactory();
        }
        calPagecount();
    }
    
    private static Session getSession(){
        return sf.getCurrentSession();
    }
    
    /**
     * 算出数据总量和总页数
     */
    public void calPagecount(){
        Session s = this.getSession();
        s.beginTransaction();
        try{
            Query q = s.createQuery(this.sql);
            List l = (List)q.list();
            this.datacount = l.size();
            if(datacount%pageSize == 0){
                this.pagecount = datacount/pageSize;
            }else{
                this.pagecount = datacount/pageSize + 1;
            }
            System.out.println(pagecount);
            s.getTransaction().commit();
        }catch(Exception e){
            s.getTransaction().rollback();
        }
    }
    
    /**
     * 获取某页的数据(首页为1)
     * @param pageno
     * @return
     */
    public List getPagingResults(int pageno){
        this.pageno = pageno;
        List l = new ArrayList();
        Session s = this.getSession();
        s.beginTransaction();
        try{
            Query q = s.createQuery(this.sql);
            q.setFirstResult((this.pageno-1)*this.pageSize).setMaxResults(this.pageSize);
            l = (List)q.list();
            /*if(l.size() <= 0){
                l = null;
            }*/
            s.getTransaction().commit();
        }catch(Exception e){
            s.getTransaction().rollback();
            return l;
        }
        return l;
    }
    
    
    /**
     * 返回每页显示数据数
     * @return
     */
    public int getPageSize() {
        return pageSize;
    }

    /**
     * 设置每页显示数据数
     * @param pageSize
     */
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    /**
     * 返回当前页码
     * @return
     */
    public int getPageno() {
        return pageno;
    }

    /**
     * 设置当前页码
     * @param pageno
     */
    public void setPageno(int pageno) {
        this.pageno = pageno;
    }

    /**
     * 返回总页数
     * @return
     */
    public int getPagecount() {
        return pagecount;
    }

    /**
     * 返回数据总数
     * @return
     */
    public int getDatacount() {
        return datacount;
    }

    /**
     * 是否有上一页
     * @return
     */
    public boolean hasPre(){
        
        return (pageno-1)>0;
    }
    
    /**
     * 是否有下一页
     * @return
     */
    public boolean hasNext(){
        
        return (pageno+1)<=pagecount;
    }
    
    /**
     * 返回传入的sql语句
     * @return
     */
    public String getSql() {
        return sql;
    }

    /**
     * 设置要查询分页的sql语句
     * @param sql
     */
    public void setSql(String sql) {
        this.sql = sql;
    }
    
    public static void main(String[] args){
        PagingUtil2 testp = new PagingUtil2("select filename from file where username='test1'", 5);
        List us = testp.getPagingResults(3);
        for(int i=0;i<us.size();i++){
            System.out.println(us.get(i).toString());
        }
    }
}