登录的servlet代码
- Java code
public class Login extends HttpServlet{ public void init(ServletConfig config) throws ServletException{ super.init(config); } public void service(HttpServletRequest req,HttpServletResponse resp) throws IOException{ HttpSession session=req.getSession(true); PrintWriter out = resp.getWriter(); String username=req.getParameter("username"); String pwd=req.getParameter("pwd"); String sql="select * from userinfo where username=? and pwd=?"; Connection conn=db.getConnection(); try{ PreparedStatement pstmt=conn.prepareStatement(sql); pstmt.setString(1,username); pstmt.setString(2,pwd); ResultSet rs=pstmt.executeQuery(); Boolean m=rs.next(); if(m==true){ session.setAttribute(username, rs.getString("username")); session.setAttribute(pwd,rs.getString("pwd")); resp.sendRedirect("index.jsp"); }else{ out.println("<SCRIPT LANGUAGE=javascript>"); out.println("alert('用户名或密码错误！');"); out.println("window.location.href='default.jsp'; "); out.println("</script>"); } pstmt.close(); conn.close(); } catch(SQLException e){ e.printStackTrace(); } }}查询数据的servlet
- Java code
public class gl extends HttpServlet{ /** * */ private static final long serialVersionUID = 1L; public void init(ServletConfig config) throws ServletException{ super.init(config); } public void service(HttpServletRequest req,HttpServletResponse resp) throws IOException{ HttpSession session=req.getSession(true); PrintWriter out = resp.getWriter(); String username=null; String lastip=null; String sql="select username，lastip from log"; Connection conn=db.getConnection(); try{ PreparedStatement pstmt=conn.prepareStatement(sql); ResultSet rs=pstmt.executeQuery(sql); Boolean m=rs.next(); if(m==true){ session.setAttribute(username,rs.getString("username")); session.setAttribute(lastip,rs.getString("lastip")); System.out.println(username); }else{ out.println("<SCRIPT LANGUAGE=javascript>"); out.println("alert('用户名或密码错误！');"); out.println("window.location.href='default.jsp'; "); out.println("</script>"); } pstmt.close(); conn.close(); } catch(SQLException e){ e.printStackTrace(); } }}登录的jsp页面
- Java code
<html> <head> <base href="<%=basePath%>"> <title>My JSP 'default.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> This is my JSP page. <br> <form action="login" name="form1" method="post"> <tr> <td>用户</td> <td><input type="text" name="username"></td> </tr> <tr> <td>密码</td> <td><input type="password" name="pwd"></td> </tr> <tr> <td height="45" colspan="2"> <p align="center"> <input type="submit" value="登 陆"> <input type="reset" value="取 消"> </td> </tr> </form> </body></html>