JSP学生管理系统修改密码 代码

好的，以下是一个简单的 JSP 学生管理系统修改密码的代码示例：

前端页面代码（change_pwd.jsp）：

<form method="post" action="ChangePwdServlet">
  旧密码：<input type="password" name="oldPwd"><br>
  新密码：<input type="password" name="newPwd"><br>
  确认密码：<input type="password" name="confirmPwd"><br>
  <input type="submit" value="修改密码">
</form>

后端 Java 代码（ChangePwdServlet.java）：

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ChangePwdServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;

  protected void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    request.setCharacterEncoding("UTF-8");
    String oldPwd = request.getParameter("oldPwd");
    String newPwd = request.getParameter("newPwd");
    String confirmPwd = request.getParameter("confirmPwd");
    String sid = (String) request.getSession().getAttribute("sid");

    if (!newPwd.equals(confirmPwd)) {
      request.setAttribute("msg", "两次输入的新密码不一致！");
      request.getRequestDispatcher("/change_pwd.jsp").forward(request, response);
      return;
    }

    try {
      Class.forName("com.mysql.jdbc.Driver");
      Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
      String sql = "SELECT * FROM student WHERE sid=? AND password=?";
      PreparedStatement pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, sid);
      pstmt.setString(2, oldPwd);
      ResultSet rs = pstmt.executeQuery();
      if (rs.next()) {
        sql = "UPDATE student SET password=? WHERE sid=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, newPwd);
        pstmt.setString(2, sid);
        pstmt.executeUpdate();
        request.setAttribute("msg", "密码修改成功！");
        request.getRequestDispatcher("/change_pwd.jsp").forward(request, response);
      } else {
        request.setAttribute("msg", "旧密码输入错误！");
        request.getRequestDispatcher("/change_pwd.jsp").forward(request, response);
      }
      rs.close();
      pstmt.close();
      conn.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

需要注意的是，以上代码仅为示例，实际应用中还需要进行更多的安全性和错误处理。同时，数据库连接信息应该写在配置文件中，而非硬编码在代码中。