JAVA分页

package png.houtai;
import java.util.*;
import java.sql.*;
import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.JspWriter;
import png.db.DB;
public class bookTag extends TagSupport {
    public bookTag() {
        try {
            jbInit();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
    private String page="1";
   private String type;
   private String id;
  public void setPage(String page) {
    if(page.equals("")||page.trim().length()<1)
                       return;
      this.page = page;
  }
  public void setId(String id){
      this.id=id;
  }
  public String getId(){
      return id;
  }
public void setType(String type) {
     this.type = type;
}
public String getPage() {
      return page;
  }
public String getType() {
     return type;
}
public int doStartTag(){
       JspWriter out=pageContext.getOut();
       int i=0;//环
       int sumrow;//总行数
       int sumye;//总页数
       int yerow;//每页行数
       int page;//待显示页码
       yerow=4;
       String strrow="";//接收intpage传来的值
       String strSQL;
       strrow=this.getPage();
       page=Integer.parseInt(strrow);
       if(page<1){
           page=1;
       }
       try{
           strSQL="select * from BookInfo";
           Statement st=null;
           ResultSet set=null;
           Connection con=null;
           DB db=new DB();
           con=db.conn();
           st=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
           set=st.executeQuery(strSQL);
           set.last();// 光标在最后一行
           sumrow=set.getRow();//每页行数
           sumye=(sumrow+yerow-1)/yerow;//总页数
           // 调整待显示的页码
           if(page>sumye){
               page=sumye;
           }
           out.print("<form method='get' action='/Root/shan'>");
         out.print(" 第" + page + "页");
         out.print(" 共" + sumye + "页");
         if (page < sumye) {
                               out.print("<a href='/Root/Manager/gaibook.jsp?id="+id+"&page=" + (page + 1)
                                               + "'>下一页</a>");
                       }
                       if (page > 1) {
                 out.print("<a href='/Root/Manager/gaibook.jsp?id="+id+"&page=" + (page - 1)
                                 + "'>上一页</a>");
         }
          out.print("<table border='1' width='170' cellspacing='0' cellpadding='0'>");
          out.print("<tr><th>选择/不选</th>");
          out.print("<th>图书编号</th>");
          out.print("<th>图书名称</th>");
          out.print("<th>图书类型</th>");
          out.print("<th>出版社名称</th>");
          out.print("<th>作者名称</th>");
          out.print("<th>图书介绍</th>");
          out.print("<th>图书价格</th>");
          out.print("<th>发行日期</th>");
          out.print("<th>上架日期</th>");
          out.print("<th>是否新书</th>");
          out.print("<th>是否推荐</th>");
          out.print("<th>图书数量</th>");
          out.print("<th>修改</th>");
          //out.print("<th>删除</th>");
          out.print("</tr>");
                               if (sumye > 0) {
                                       // 将记录指针定位到待显示页的第一条记录上
                                       set.absolute((page - 1) * yerow + 1);
                                       // 显示数据
                                       i = 0;
                                       String user_id, user_name;
                                       // 遍历记录集，注意判断结束的方法
                                       while (i < yerow && !set.isAfterLast()) {
                                               // 获取记录
                                               String BookConver=set.getString(1);
                                               String BookId=set.getString(2);
                                               String BookName=set.getString(3);
                                               String BookType=set.getString(4);
                                               String BookPubliSher=set.getString(5);
                                               String BookAuthor=set.getString(6);
                                               String Bookintorduce=set.getString(7);
                                               String BookPrice=set.getString(8);
                                               String BookDate =set.getString(9);
                                               String BookIntime=set.getString(10);
                                               String BookNewBook=set.getString(11);
                                               String BookCommend=set.getString(12);
                                               String BookSum=set.getString(13);
                                               out.print("<tr>");
                                               out.print("<td ><input type='checkbox' name='id' value='"+BookId+"'/></td>");
                                               out.print("<td ><input type='text' name='BookId' id='BookId' value='"+BookId+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookName' value='"+BookName+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookType' value='"+BookType+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookPubliSher' value='"+BookPubliSher+"' readonly='readonly'/></td>");
                                               out.print("<td ><input type='text' name='BookAuthor' value='"+BookAuthor+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='Bookintorduce' value='"+Bookintorduce+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookPrice' value='"+BookPrice+"' readonly='readonly'/></td>");
                                               out.print("<td ><input type='text' name='BookDate' value='"+BookDate+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookIntime' value='"+BookIntime+"' readonly='readonly' /></td>");
                                               out.print("<td ><input type='text' name='BookNewBook' value='"+BookNewBook+"' readonly='readonly'/></td>");
                                               out.print("<td ><input type='text' name='BookCommend' value='"+BookCommend+"' readonly='readonly'/></td>");
                                               out.print("<td ><input type='text' name='BookSum' value='"+BookSum+"' readonly='readonly'/></td>");
                                               out.print("<td ><a href='gai.jsp?BookId="+BookId+"'>修改</a></td>");
                                               set.next();
                                               i++;
                                       }
                                   }
                                   out.print("<tr><td  colspan='15' align='center'><input type='submit' name='gai' value='删除' /></td></tr>");
                               out.print(" </table>");
                               out.print(" </form>");
                       // 关闭结果集
                       set.close();
                       // 关闭SQL语句对象
                       st.close();
                       // 关闭数据库
                       con.close();
       }catch(Exception e){
           System.out.print(e.getMessage());
       }
        return this.SKIP_BODY;
    }
    private void jbInit() throws Exception {
    }
}