關于分級自測題，我們知道該系統一共分為兩個角色，一個是讀者，一個是管理者，我們需要根據不同使用者去到不同的頁面，是以我們需要寫一個登陸界面。
本文先寫這個功能的實作，該功能主要在servlet裡面實作。
一.先寫jsp頁面
<%@ page language="java" contentType="text/html; charset=UTF-8"//denglu.jsp
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>圖書管理系統：登陸界面</title>
</head>
<body>
<%
Object message = request.getAttribute("message");
if(message!=null && !"".equals(message)){
%>
<script type="text/javascript">
alert("<%=request.getAttribute("message")%>");
</script>
<%} %>
<%
Object message1 = request.getAttribute("message1");//顯示注冊成功（下一篇部落格）
if(message1!=null && !"".equals(message1)){
%>
<script type="text/javascript">
alert("<%=request.getAttribute("message1")%>");
</script>
<%} %>
<form action="login_servlet?method=login" method="post">
<table align="center" border="1" width="500">
<tr>
<td>賬号: </td>
<td>
<input type="text" name="studentid" id="studentid" />
</td>
</tr>
<tr>
<td>密碼: </td>
<td>
<input type="password" name="password"/>
</td>
</tr>
<tr>
<td>身份: </td>
<td>
<select name="form">//這裡傳值給servlet
<option value="讀者"selected>讀者</option>
<option value="管理者"selected>管理者</option>
</select>
</td>
</tr>
<tr align="center">
<td colspan="2">
<input type="submit" value="登入" onclick="return judge()" />
<a href="zhuce.jsp" >點選注冊</a>
</td>
</tr>
</table>
</body>
</html> reader.jsp//讀者功能
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" import="Bean.*,java.util.ArrayList,util.*,dao.*,servlet.*"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="book_servlet?method=looklist" ><h3>浏覽圖書資訊</h3></a>
<a href="goodbook1.jsp" ><h3>查詢圖書資訊</h3></a>
<a href="book_servlet?method=delist" ><h3>借閱圖書</h3></a>
<a href="book_servlet?method=borrowlist&borrower=<%=good.getStudentid()%>"><h3>浏覽催還書目</h3></a>
<a href="book_servlet?method=cuihuan" ><h3>歸還圖書</h3></a>
</body>
</html> genlist.jsp//管理者功能
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" import="Bean.*,java.util.ArrayList,util.*,dao.*,servlet.*"%>
<html>
<head>
<meta charset="UTF-8">
<title>管理者界面</title>
</head>
<body>
<a href="addstudent.jsp" ><h3>添加讀者資訊</h3></a>
<a href="addbook.jsp" ><h3>添加新書資訊</h3></a>
<a href="update.jsp" ><h3>列印催還書資訊</h3></a>
</body>
</html> 二.servlet層
package servlet;
import java.io.IOException;
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 javax.servlet.http.HttpSession;
import Bean.xinxi;
import dao.dao;
import daoimpl.daoimpl;
/**
* Servlet implementation class login_servlet
*/
@WebServlet("/login_servlet")
public class login_servlet extends HttpServlet {
private static final long serialVersionUID = 1L;
dao gooddao=new daoimpl();
/**
* @see HttpServlet#HttpServlet()
*/
public login_servlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
String method=request.getParameter("method");
String form=request.getParameter("form");//擷取來自denglu.jsp裡面的資料if("login".equals(method)) { //通過判斷語句進入不同頁面if(form.equals("讀者"))request.getRequestDispatcher("reader.jsp").forward(request, response);
else if(form.equals("管理者"))request.getRequestDispatcher("genlist.jsp").forward(request, response);
}
} 三.運作結果
這裡隻是一個前端頁面，沒有與資料庫打交道，下一篇寫驗證賬号密碼是否正确，需要實作注冊功能，連接配接資料庫。
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