JSP(JavaServer Pages)是一种用于创建动态网页的技术,它允许在HTML或XML文档中嵌入Java代码片段和表达式。JSP网页投票系统是一种常见的应用,用于收集用户的意见和偏好。
JSP网页投票系统通常包括以下几个组件:
以下是一个简单的JSP网页投票系统的示例代码:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>投票页面</title>
</head>
<body>
<h1>请选择您最喜欢的颜色</h1>
<form action="processVote.jsp" method="post">
<input type="radio" name="color" value="red"> 红色<br>
<input type="radio" name="color" value="blue"> 蓝色<br>
<input type="radio" name="color" value="green"> 绿色<br>
<input type="submit" value="投票">
</form>
</body>
</html>
<%@ page import="java.sql.*" %>
<%
String color = request.getParameter("color");
Connection conn = null;
PreparedStatement pstmt = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/votingdb", "username", "password");
String sql = "UPDATE votes SET count = count + 1 WHERE color = ?";
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, color);
pstmt.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (pstmt != null) pstmt.close();
if (conn != null) conn.close();
}
response.sendRedirect("results.jsp");
%>
<%@ page import="java.sql.*" %>
<%
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/votingdb", "username", "password");
stmt = conn.createStatement();
rs = stmt.executeQuery("SELECT color, count FROM votes");
%>
<html>
<head>
<title>投票结果</title>
</head>
<body>
<h1>投票结果</h1>
<table border="1">
<tr>
<th>颜色</th>
<th>票数</th>
</tr>
<% while (rs.next()) { %>
<tr>
<td><%= rs.getString("color") %></td>
<td><%= rs.getInt("count") %></td>
</tr>
<% } %>
</table>
</body>
</html>
<%
} catch (Exception e) {
e.printStackTrace();
} finally {
if (rs != null) rs.close();
if (stmt != null) stmt.close();
if (conn != null) conn.close();
}
%>
问题1:投票结果不更新
问题2:投票数异常增加
问题3:页面加载缓慢
通过以上示例和分析,您可以构建一个基本的JSP网页投票系统,并了解常见问题的解决方法。
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