学生选课管理系统

package servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import dao.DBUtil; public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); PrintWriter out = null; out = response.getWriter(); String sname = request.getParameter("sname"); String sid = request.getParameter("sid"); String login = request.getParameter("radio"); if (login != null) { if (login.equals("student")) { try { Connection conn = DBUtil.getConn(); String sql = "select * from student where sname=? and sid=?"; PreparedStatement pstm; pstm = conn.prepareStatement(sql); pstm.setString(1, sname); pstm.setString(2, sid); ResultSet rs = pstm.executeQuery(); if (rs.next()) { HttpSession session = request.getSession(); session.setAttribute("sname", sname); session.setAttribute("sid", sid); request.getRequestDispatcher("student.jsp").forward( request, response); } else { out.println("<script language='javascript'>alert('用户名或密码错误，请重新输入');</script>"); request.getRequestDispatcher("login.jsp").include( request, response); } } catch (Exception e) { out.println("<script language='javascript'>alert('用户名或密码错误，请重新输入');</script>"); request.getRequestDispatcher("login.jsp").include(request, response); e.printStackTrace(); } } if (login.equals("admin")) { if (sname.equals("admin")) { if (sid.equals("2013")) { request.getRequestDispatcher("admin.jsp").forward( request, response); }else{ out.println("<script language='javascript'>alert('用户名或密码错误，请重新输入');</script>"); request.getRequestDispatcher("login.jsp").include(request, response); } }else{ out.println("<script language='javascript'>alert('用户名或密码错误，请重新输入');</script>"); request.getRequestDispatcher("login.jsp").include(request, response); } } } else{ request.getRequestDispatcher("login.jsp").include(request, response); } } }