5-2查询问题

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="cn.imooc.b.*,cn.imooc.b.*,java.util.*"%>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<%
   String basePath=request.getScheme()+"://"+request.getServerName()+":"+
                 request.getServerPort()+request.getContextPath();
%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>图书查询</title>
<script type="text/javascript" src="<%=basePath%>/resources/js/jquery-1.4.2.js"></script>
</head>
<body>
    <center>
        <h1>图书查询</h1>
        <p>
            图书ID：<input type="text" name="bookID">
            图书名：<input type="text" name="bookName">
            分类：<input type="text" name="catgoryName">
            <input type="button" value="查询" id="search">
        </p>
        <hr>
        <table width="800px" cellspacing="0px" cellpadding="0px" border="1px">
            <thead>
                <tr>
                    <th>图书ID</th>
                    <th>书名</th>
                    <th>分类</th>
                    <th>价格</th>
                    <th>描述</th>
                </tr>
            </thead>
            <%
            LibDaolmpl ld=new LibDaolmpl();
            List list=ld.getBooks();
            List<Book>list2=(List<Book>)this.getServletContext().getAttribute("bookList");
            if(list2==null){
            for(int i=0;i<list.size();i++){
            Book book=(Book)list.get(i);
            %>
            <tbody id="cont">
             
                    <tr>
                        <td><%=book.getId() %></td>
                        <td><%=book.getName() %></td>
                        <td><%=book.getClassName() %></td>
                        <td><%=book.getPrice() %></td>
                        <td><%=book.getDescription() %></td>
                    </tr>
                 
            </tbody>
            <%} 
            }else{
                for(int i=0;i<list2.size();i++){
                    Book book=(Book)list2.get(i);
            %>
            <tbody id="cont">
                 
                    <tr>
                        <td><%=book.getId() %></td>
                        <td><%=book.getName() %></td>
                        <td><%=book.getClassName() %></td>
                        <td><%=book.getPrice() %></td>
                        <td><%=book.getDescription() %></td>
                    </tr>
                 
            </tbody>
            <%
                }
                }
            %>
        </table>
    </center>
</body>
<script type="text/javascript">
  $("#search").click(function(){
      $.ajax({
         url:"<%=basePath%>/SearchServlet",
         type:"post",
         data:{
             bookID:$("input[name=bookID]").val(),
             bookName:$("input[name=bookName]").val(),
             catgoryName:$("input[name=catgoryName]").val()
         },
         dataType:"json",
         success:function(result){
              
         }
      });
  })
</script>
</html>

package cn.imooc.servlet;
 
import java.io.IOException;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.json.JSONObject;
 
import cn.imooc.b.Book;
import cn.imooc.b.LibDaolmpl;
 
public class SearchServlet extends HttpServlet {
 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String bookID=request.getParameter("bookID");
        String bookName=request.getParameter("bookName");
        String catgoryName=request.getParameter("catgoryName");
        LibDaolmpl ld=new LibDaolmpl();
        List<Book>list=ld.getBooksByCondition(bookID, bookName, catgoryName);
        this.getServletContext().setAttribute("bookList", list);
        request.getRequestDispatcher(request.getContextPath()+"/showBooks.jsp");
        System.out.println("Search"+bookID);
        System.out.println("search"+list.toString());
//      JSONObject jsonObject=new JSONObject("{flag:false}");
//      response.getOutputStream().write(jsonObject.toString().getBytes("utf-8"));
    }
 
     
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
 
}