jsp登录和注册源代码

JSP（JavaServer Pages）是一种用于创建动态Web内容的技术，它允许开发者在HTML页面中嵌入Java代码。下面是一个简单的JSP登录和注册页面的示例代码。

登录页面 (login.jsp)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Login</title>
</head>
<body>
    <h2>Login</h2>
    <form action="authenticate.jsp" method="post">
        Username: <input type="text" name="username"><br><br>
        Password: <input type="password" name="password"><br><br>
        <input type="submit" value="Login">
    </form>
</body>
</html>

注册页面 (register.jsp)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Register</title>
</head>
<body>
    <h2>Register</h2>
    <form action="registerProcess.jsp" method="post">
        Username: <input type="text" name="username"><br><br>
        Password: <input type="password" name="password"><br><br>
        Email: <input type="email" name="email"><br><br>
        <input type="submit" value="Register">
    </form>
</body>
</html>

认证处理页面 (authenticate.jsp)

<%@ page import="java.sql.*" %>
<%
    String username = request.getParameter("username");
    String password = request.getParameter("password");

    // 这里应该使用预编译语句来防止SQL注入
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
        pstmt = conn.prepareStatement("SELECT * FROM users WHERE username=? AND password=?");
        pstmt.setString(1, username);
        pstmt.setString(2, password);
        rs = pstmt.executeQuery();

        if (rs.next()) {
            session.setAttribute("username", username);
            response.sendRedirect("welcome.jsp");
        } else {
            out.println("Invalid login credentials. Please try again.");
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        // 关闭资源
        try { if (rs != null) rs.close(); } catch (Exception e) {}
        try { if (pstmt != null) pstmt.close(); } catch (Exception e) {}
        try { if (conn != null) conn.close(); } catch (Exception e) {}
    }
%>

注册处理页面 (registerProcess.jsp)

<%@ page import="java.sql.*" %>
<%
    String username = request.getParameter("username");
    String password = request.getParameter("password");
    String email = request.getParameter("email");

    Connection conn = null;
    PreparedStatement pstmt = null;
    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
        pstmt = conn.prepareStatement("INSERT INTO users (username, password, email) VALUES (?, ?, ?)");
        pstmt.setString(1, username);
        pstmt.setString(2, password);
        pstmt.setString(3, email);
        pstmt.executeUpdate();

        response.sendRedirect("login.jsp");
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        // 关闭资源
        try { if (pstmt != null) pstmt.close(); } catch (Exception e) {}
        try { if (conn != null) conn.close(); } catch (Exception e) {}
    }
%>