1.运行这个，报出这样的错误。
2.
package com.Dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.beans.Book;
import com.tools.DBConnection;
public class PageQueryDao {
//分页查询所有书目信息
public List<Book> getPageList(int page){
List<Book> list = new ArrayList<Book>();
DBConnection DB = new DBConnection();
Connection conn=DB.getCon();
int m = (page-1)*Book.PAGE_SIZE;
if( m > 0 || m == 0){
String sql = "select top 6 * from books where BookID > "+ m ;
//String sql="select * from books order by BookID asc limit ?,?";//limit关键字
try {
PreparedStatement pstm=conn.prepareStatement(sql);
//pstm.setInt(1, (page-1)*Book.PAGE_SIZE); //设置查询记录的开始位置
//pstm.setInt(2, Book.PAGE_SIZE); //设置查询数据所返回的记录数
ResultSet rs = pstm.executeQuery();
while(rs.next()){
Book book=new Book();
book.setBookId(rs.getInt("BookID"));
book.setName(rs.getString("Name"));
book.setAuthor(rs.getString("Author"));
book.setPublisher(rs.getString("Publisher"));
book.setPrice(rs.getString("Price"));
list.add(book);
}
rs.close();
pstm.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return list;
}
//查询总记录数
public int FindCounts(){
int count=0;
DBConnection DB=new DBConnection();
Connection conn=DB.getCon();
String sql="select count(*) from books";
try {
PreparedStatement pstm=conn.prepareStatement(sql);
ResultSet rs=pstm.executeQuery();
if(rs.next()){//rs里就一个值
count=rs.getInt(1);
}
rs.close();
conn.close();
} catch (SQLException e){
// TODO Auto-generated catch block
e.printStackTrace();
}
return count;
}
/*public static void main(String[] args){
System.out.println((getPageList(0)).size() );
System.out.println((getPageList(1)).size() );
List<Book> list = getPageList(0);
if(list != null){
for(Book b:list){
System.out.println(b.getBookId());
System.out.println(b.getName());
System.out.println(b.getPrice());
System.out.println(b.getPublisher());
System.out.println(b.getAuthor());
}
}
}*/
3.<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@page import="java.util.List"%><%@page import="com.beans.Book"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
图书信息列表 <!-- --> a:link{color:#FF4500;text-decoration:none}/*未访问，红色，无下划线*/ a:active{color:blue;}/*激活，红色*/ a:visited{color:red;text-decoration:none}/*已访问，紫色，无下划线*/ a:hover{color:yellow;text-decoration:underline}/*鼠标移动上面，蓝色，下划线*/ 喵喵网上书店 | |||||
|
书 名:<%=b.getName() %> 作 者:<%=b.getAuthor() %> 出 版:<%=b.getPublisher() %> 价 格:<%=b.getPrice() %> <%= request.getAttribute("bar") %> | |||||
4.package com.servlets;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.Dao.PageQueryDao;import com.beans.Book;public class PageQueryServlet extends HttpServlet { /** * */ private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { int currpage=1; // if(request.getParameter("page") != null){ // currpage = Integer.parseInt(request.getParameter("page")); // } PageQueryDao pagedao = new PageQueryDao(); List list = pagedao.getPageList(currpage);//查询当前页记录 request.setAttribute("list", list); int pages; //计算查询总页数 int count = pagedao.FindCounts(); if(count%Book.PAGE_SIZE == 0){ pages = count/Book.PAGE_SIZE; } else{ pages = count/Book.PAGE_SIZE+1; } System.out.println(pages); StringBuffer sb=new StringBuffer(); //构建分页条 for(int i = 1;i <= pages;i++){ if(i == currpage){ sb.append("『" + i + "』"); } else{ sb.append(" 下一页 "); } sb.append(" "); } request.setAttribute("bar", sb.toString()); request.getRequestDispatcher("books.jsp").forward(request, response); //请求转发 } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }}
就是这几个文件，数据库能成功连接。PageDao中的主函数能成功运行。就是jsp中无法获取list中的信息。PageServlet无法运行显示出books.jsp界面的相关信息。
希望大神们赐教。
