用户登录注册留言习题

登录页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录页</title>

<script type="text/javascript">        //添加函数
function check()
{
    var uid =document.getElementById("userid");     
    if(uid.value =="")                               //判断输入的值是否为空
        {
        alert("代码不能为空");
        return false;                 //返回false，。使后面的按钮不能执行        
}  
    if(uform.password.value=="")
        {
        alert("密码不能为空");
        return false;
        }
    return true;
    }
</script>
</head>
<body>
<form id="uform" action ="yanzheng.jsp" method="post" onSubmit="return check();">
用户：<input id="userid" type="text" name="userid" width=30/><br>
密码：<input id="passeord" type="password" name="password" width=30/><br>
<input type="submit" value="登录" />
<a href ="zhuce.jsp">注册新用户</a>

</form>







</body>
</html>

登录页

错误提示页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@page import="java.util.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>消息页面</title>
</head>
<body>

<%
String strMsgId =request.getParameter("msgid");
if(strMsgId == null || strMsgId.trim().length()==0)
{
    out.print("信息错误");
}
else
{
    int iMsgid = Integer.parseInt(strMsgId);
    switch (iMsgid)
    {
    case 1:
        out.print("账号输入错误");
    break;
    case 2:
        out.print("密码输入错误");
    break;
    case 3:
        out.print("密码错误");
    break;
    case 4:
        out.print("用户不存在");
    break;
    case 5:
        out.print("请正确输入用户名");
    break;
    case 6:
        out.print("提交成功");
    break;
    case 7:
        out.print("用户代码已存在");
    break;
    
    case 8:
        out.print("请重新登录系统");
    break;
    
    default:
        out.print("无法识别信息");
        break;
    }
}
response.setHeader("refresh","2;URL=login.jsp");    //信息错误跳转回login.jsp
  
%>



</body>
</html>

错误提示页

保存页信息页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>保存用户信息</title>
</head>
<body>

<%
  //接收用户信息
String strUserid =request.getParameter("userid");
String strUsername =request.getParameter("username");
String strPW =request.getParameter("password");

//判断用户输入的信息是否为空
if(strUserid == null || strUserid.trim().length() == 0)  
{
    response.sendRedirect("massage.jsp?msgid=1");
}
else if(strUsername == null || strUsername.trim().length() == 0)
{
    response.sendRedirect("massage.jsp?msgid=5");
}else if(strPW == null || strPW.trim().length() == 0)
{
    response.sendRedirect("massage.jsp?msgid=2");
}
else                                                           //查找用户信息
{
    Object obj=application.getAttribute(strUserid);
    if(obj!=null){
        response.sendRedirect("massage.jsp?msgid=7");
    }
    else{
    strUsername=new String(strUsername.getBytes("ISO-8859-1"),"UTF-8");
    
    String strUser=strUserid+"#"+strUsername+"#"+strPW;
    
    application.setAttribute(strUserid,strUser);
    
    response.sendRedirect("massage.jsp?msgid=6");   
    }
}
%>







</body>
</html>

保存信息页

验证页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登陆验证页</title>
</head>
<body>

<%
String strUserid =request.getParameter("userid");
String strPW =request.getParameter("password");
if(strUserid == null || strUserid.trim().length() == 0)
{
    response.sendRedirect("massage.jsp?msgid=1");
}
else if(strPW == null || strPW.trim().length() == 0)
{
    response.sendRedirect("massage.jsp?msgid=2");
}
else
{//查找用户信息
    Object obj=application.getAttribute(strUserid);
    if(obj!=null){
        String strUser=obj.toString();
        String[] user= strUser.split("#");
        
    String strUID =user[0];
    String strUsername =user[1];
    String strP =user[2];
    
    
        if(strPW.equals(strP))
        {
            out.print("欢迎"+strUsername+"登陆");

            //跳转到系统页面

            session.setAttribute("login",strUsername);
            
    
            
        }
        else
        {
            response.sendRedirect("massage.jsp?msgid=3");
        }
        
    }
    else
    {
        response.sendRedirect("massage.jsp?msgid=4");
    }
}
%>
<br><br><br>
<a href="liuyan.jsp">留言簿</a>














</body>
</html>

验证页

留言页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@page import="java.util.*" %>
    <%@page import="java.text.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>留言簿</title>

<%

String userName ="";

//检查登录状态
Object oo =session.getAttribute("login");

if(oo==null)
{
    response.sendRedirect("massage.jsp?msgid=8");
}
else
{
    userName=oo.toString();
}



String liuy = request.getParameter("liuyan");
//if(liuy != null && liuy.length()!=0)
//if(liuy != null && liuy !=null)
if(liuy != null && !liuy.trim().equals(""))     //判断liuy不能为空且也不能为空字符串以及去掉空格
{
    String strLiuy =new String(liuy.getBytes("ISO-8859-1"),"UTF-8");   //进行转码
    
    
    //附加时间信息

    Date dt=new Date();

    //格式化时间

    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd-hh:mm:ss");
    
    strLiuy += "&nbsp;&nbsp;&nbsp;  "+ df.format(dt)+"&nbsp;&nbsp;"+"留言人："+userName;
    
    
    Object obj = application.getAttribute("liuy");    //取出留言
    
    ArrayList<String> A;
    
    if(obj==null)
    {
       A=new ArrayList<String>();
    }
    else
    {
        A= (ArrayList<String>)obj;
    }
    
    A.add(strLiuy);

    application.setAttribute("liuy",A);

}


%>

</head>
<body>

<form>

最新留言：<br><br>

<%

int i=1;

Object obj = application.getAttribute("liuy");    //取

if(obj!=null)
{
    ArrayList<String> A= (ArrayList<String>)obj;

for(int m= A.size()-1;m>=0;m--)
{
    out.print(i+". "+A.get(m)+"<br>");
    i++;
}
}
%>

留言内容：
<br>

<textarea rows="10" cols="30" name="liuyan"></textarea><br>

<input type="submit" value="提交">



</form>

</body>
</html>

留言页