12.4

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.sql.*" %>

<%
    request.setCharacterEncoding("UTF-8");
    String id = (String) session.getAttribute("id1");
    String destination = request.getParameter("destination");
    String departuredate = request.getParameter("departuredate");
    String returndate = request.getParameter("returndate");
    String Type = request.getParameter("Type");
    String Typecontent = request.getParameter("Typecontent");
    String Reason = request.getParameter("Reason");
    String State = "待审批";

    // 数据库连接信息
    String dbURL = "jdbc:mysql://localhost:3306/gs?useSSL=false";
    String dbUsername = "root";
    String dbPassword = "123456";

    Connection connection = null;
    PreparedStatement statement = null;
    ResultSet rs = null;
    try {
        // 连接数据库
        Class.forName("com.mysql.jdbc.Driver");
        connection = DriverManager.getConnection(dbURL, dbUsername, dbPassword);
        // 检查学生是否存在
        String checkSql = "SELECT * FROM class1 WHERE ID = ? AND State =?";
        PreparedStatement checkStatement = connection.prepareStatement(checkSql);
        checkStatement.setString(1, id);
        checkStatement.setString(2, State);
        rs = checkStatement.executeQuery();

        if (rs.next()) {
            // 学生存在，更新信息
            // 修改学生信息的SQL语句
            String updateSql = "UPDATE class1 SET destination = ?, departuredate = ?,returndate = ?,Type = ?,Typecontent = ?,Reason = ?WHERE ID = ?";
            // 创建PreparedStatement对象
            statement = connection.prepareStatement(updateSql);
            // 设置参数值
            statement.setString(1, destination);
            statement.setString(2, departuredate);
            statement.setString(3, returndate);
            statement.setString(4, Type);
            statement.setString(5, Typecontent);
            statement.setString(6, Reason);
            statement.setString(7, id);
            // 执行更新操作
            int rowsAffected = statement.executeUpdate();

            // 检查更新结果
            if (rowsAffected > 0) {
                out.println("学生信息更新成功！");
            } else {
                out.println("学生信息更新失败！");
            }
        } else {
            out.println("学生不存在，无法更新信息！");
        }
    } catch (Exception e) {
        // 处理异常情况
        out.println("更新学生信息失败：" + e.getMessage());
    } finally {
        // 关闭ResultSet、PreparedStatement和数据库连接
        if (rs != null) {
            rs.close();
        }
        if (statement != null) {
            statement.close();
        }
        if (connection != null) {
            connection.close();
        }
    }
%>