《JavaWeb编程技术》课后习题答案(12)
时间:2025-07-10
时间:2025-07-10
String sql="SELECT * FROM public.books";
Statement stmt = dbconn.createStatement();
ResultSet rst = stmt.executeQuery(sql);
ResultSetMetaData rstmd = rst.getMetaData();
out.println("结果集列数:"+rstmd.getColumnCount()+"</br>");
out.println("第3列标题:"+rstmd.getColumnLabel(3)+"</br>");
out.println("第3列名:"+rstmd.getColumnName(3)+"</br>");
out.println("第3列类型:"+rstmd.getColumnType(3)+"</br>");
out.println("第3列类型名:"+rstmd.getColumnTypeName(3)+"</br>"); }catch(ClassNotFoundException e1){
out.println(e1);
}catch(SQLException e2){
out.println(e2);
}
%>
</body></html>
9. 按教材7.7.2节建立局部或全局数据源sampleDS。创建程序7.9的CustomerBean.java程序和程序7.10的SampleDAO.java程序。
SelectCustomerServlet.java代码如下:
package com.control;
import java.io.*;
import java.sql.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.model.CustomerBean;
import com.model.SampleDAO;
public class SelectCustomerServlet extends HttpServlet{
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
SampleDAO dao = new SampleDAO();
ArrayList<CustomerBean> custs = dao.selectCustomer();
request.setAttribute("custs", custs);
RequestDispatcher view = getServletContext().
getRequestDispatcher("/displayCustomer.jsp");
view.forward (request,response);
}
}
displayCustomer.jsp页面代码如下:
<%@ page contentType="text/html; charset=gb2312" %>
<%@ page import="com.model.CustomerBean,java.util.*" %>
<html><head> <title>Display Customer</title></head>
<body>
<%
ArrayList<CustomerBean> custs =