divpage.java~5~

jsp设计的留言板,供大家参考,使用的是文本文件作为数据库

package bookutil;
import java.util.ArrayList;
public class DivPage {
  public int cur_page=1;
  public int total_page=1;
  public DivPage() {
  }
  public int divPage(int len,int pagesize,String curpage){
    if(len<=0||pagesize<=0){
      return -1;
    }
    int rec_pos=0;
    total_page=(len+pagesize-1)/pagesize;
    try{
      cur_page=Integer.parseInt(curpage);
    }catch(Exception e){
      cur_page=1;
    }
    if(cur_page<=0)cur_page=1;
    if(cur_page>total_page)cur_page=total_page;
    rec_pos=(cur_page-1)*pagesize;
    return rec_pos;
  }
}