jsp留言板制作代码

JSP（Java Server Pages）是一种基于Java技术的动态网页技术，它允许在HTML或XML等静态页面中嵌入Java代码，从而实现动态内容的生成。下面是一个简单的JSP留言板制作代码示例：

1. 创建数据库表

首先，需要在数据库中创建一个表来存储留言信息。假设使用MySQL数据库，表结构如下：

CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    content TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

2. 创建JSP页面

留言表单页面（message_form.jsp）

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>留言板</title>
</head>
<body>
    <h2>留言</h2>
    <form action="submit_message.jsp" method="post">
        用户名: <input type="text" name="username"><br><br>
        内容: <textarea name="content" rows="4" cols="50"></textarea><br><br>
        <input type="submit" value="提交">
    </form>
</body>
</html>

提交留言页面（submit_message.jsp）

<%@ page import="java.sql.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>提交留言</title>
</head>
<body>
<%
    String username = request.getParameter("username");
    String content = request.getParameter("content");

    Connection conn = null;
    PreparedStatement pstmt = null;

    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/your_database", "username", "password");
        String sql = "INSERT INTO messages (username, content) VALUES (?, ?)";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, username);
        pstmt.setString(2, content);
        pstmt.executeUpdate();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (pstmt != null) pstmt.close();
        if (conn != null) conn.close();
    }
%>
    <h2>留言已提交</h2>
    <a href="view_messages.jsp">查看所有留言</a>
</body>
</html>

查看留言页面（view_messages.jsp）

<%@ page import="java.sql.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>查看留言</title>
</head>
<body>
    <h2>所有留言</h2>
    <ul>
<%
    Connection conn = null;
    Statement stmt = null;
    ResultSet rs = null;

    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/your_database", "username", "password");
        stmt = conn.createStatement();
        rs = stmt.executeQuery("SELECT * FROM messages ORDER BY created_at DESC");

        while (rs.next()) {
            String username = rs.getString("username");
            String content = rs.getString("content");
            Timestamp createdAt = rs.getTimestamp("created_at");
%>
            <li><strong><%= username %></strong> 于 <%= createdAt %> 留言: <%= content %></li>
<%
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (rs != null) rs.close();
        if (stmt != null) stmt.close();
        if (conn != null) conn.close();
    }
%>
    </ul>
    <a href="message_form.jsp">返回留言表单</a>
</body>
</html>