LiKe329994129
逆流的飞鱼
2020-01-08 20:26
采纳率: 0%
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本人是初学者看一些代码有些不懂,还请大神指点一下,谢谢

${ msg }表示什么意思呢???
index.jsp怎么跳转到main.jsp呢???

index.jsp

<html >
<title>聊天室</title>
<link href="CSS/style.css" rel="stylesheet">
<script type="text/javascript">
    function check(){
        if(document.getElementById("form1").username.value==""){
            alert("请输入用户名!");
            document.getElementById("form1").username.focus();
            return false;
        }

        if(document.getElementById("form1").password.value==""){
            alert("请输入密码名!");
            document.getElementById("form1").password.focus();
            return false;
        }
    }
</script>
<body>
    <br>
    <center><h3 style="color:red;">${ msg }</h3></center>
    <form id="form1" name="form1" method="post" action="${pageContext.request.contextPath }/user" onSubmit="return check()">
        <input type="hidden" name="method" value="login">
        <table width="371" height="230" border="0" align="center" cellpadding="0" cellspacing="0" background="images/login.jpg">
            <tr>
                <td height="120" colspan="3" class="word_dark">&nbsp;</td>
            </tr>
            <tr>
                <td width="53" align="center" valign="top" class="word_dark">&nbsp;</td>
                <td width="216" align="center" valign="top" class="word_dark">
                <table width="100%" height="100%">
                        <tr>
                            <td>用户名:</td>
                            <td><input type="text" name="username" class="login"></td>
                        </tr>
                    </table>
                </td>
                <td width="94" valign="top" class="word_dark"></td>
            </tr>

            <tr>
                <td width="53" align="center" valign="top" class="word_dark">&nbsp;</td>
                <td width="216" align="center" valign="top" class="word_dark">
                    <table width="100%" height="100%">
                        <tr>
                            <td>密&nbsp;&nbsp;码:</td>
                            <td><input type="password" name="password" class="login"></td>
                        </tr>
                    </table>
                </td>
                <td width="94" valign="top" class="word_dark"></td>
            </tr>
            <tr>
                <td width="53" align="center" valign="top" class="word_dark">&nbsp;</td>
                <td width="216" align="center" valign="top" class="word_dark">
                <input name="Submit" type="submit" class="btn_bg" value="进 入">
                </td>
                <td width="94" valign="top" class="word_dark">
                </td>
            </tr>
        </table>
    </form>
</body>
</html>

main

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ include file="safe.jsp"%>
<html>
<head>
<title>聊天室</title>
<link href="CSS/style.css" rel="stylesheet">
<script type="text/javascript" src="${ pageContext.request.contextPath }/js/jquery-1.8.3.js"></script>
<script type="text/javascript">
var sysBBS = "<span style='font-size:14px; line-height:30px;'>欢迎光临心之语聊天室,请遵守聊天室规则,不要使用不文明用语。</span><br><span style='line-height:22px;'>";var sysBBS = "<span style='font-size:14px; line-height:30px;'>欢迎光临心之语聊天室,请遵守聊天室规则,不要使用不文明用语。</span><br><span style='line-height:22px;'>";
    window.setInterval("showContent();",1000);
    window.setInterval("showOnLine();",10000);
    window.setInterval("check();",1000);
    // Jquery:JS框架.
    // 相当于window.onload
    $(function(){
        showOnLine();
        showContent();
        check();
    });

    function check(){
        $.post("${pageContext.request.contextPath}/user?method=check",function(data){
            if(data == 1){
                // 提示用户下线了
                alert("用户已经被踢下线了!");
                // 回到登录页面!
                window.location = "index.jsp";
            }
        });
    }

    // 显示在线人员列表
    function showOnLine(){
        // 异步发送请求 获取在线人员列表
        // Jquery发送异步请求
        $.post("${pageContext.request.contextPath}/online.jsp?"+new Date().getTime(),function(data){
            // $("#online") == document.getElementById("online");
            $("#online").html(data);
        });
    }

    // 显示聊天的内容
    function showContent(){
        $.post("${pageContext.request.contextPath}/user?"+new Date().getTime(),{'method':'getMessage'},function(data){
            $("#content").html(sysBBS+data);
        });
    }

    function set(selectPerson){ //自动添加聊天对象
        if(selectPerson != "${existUser.username}"){
                form1.to.value=selectPerson;
        }else{
            alert("请重新选择聊天对象!");
        }
    }

    function send(){
        if(form1.to.value==""){
            alert("请选择聊天对象!");
            return false;
        }
        if(form1.content.value==""){
            alert("发送信息不可以为空!");
            form1.content.focus();
            return false;
        }
        // $("#form1").serialize():让表单中所有的元素都提交.
        // jquery提交数据.{id:1,name:aa,age:25}
        $.post("${pageContext.request.contextPath}/user?"+new Date().getTime(),$("#form1").serialize(),function(data){
            $("#content").html(sysBBS+data+"</span>");
        });
    }

    function exit(){
        alert("欢迎您下次光临!");
        window.location.href="${pageContext.request.contextPath}/user?method=exit";
    }

    function checkScrollScreen(){
        if(!$("#scrollScreen").attr("checked")){
            $("#content").css("overflow","scroll");
        }else{
            $("#content").css("overflow","hidden");
            //当聊天信息超过一屏时,设置最先发送的聊天信息不显示
            //alert($("#content").height());
            $("#content").scrollTop($("#content").height()*2);
        }
        setTimeout('checkScrollScreen()',500);
    }
</script>

</head>
<body>

    <table width="778" height="150" border="0" align="center"
        cellpadding="0" cellspacing="0" background="images/top.jpg">
        <tr>
            <td>&nbsp;</td>
        </tr>
    </table>
    <table width="778" height="276" border="0" align="center"
        cellpadding="0" cellspacing="0">
        <tr>
            <td width="165" valign="top" bgcolor="#f6fded" id="online" style="padding:5px">在线人员列表</td>
            <td width="613" height="200px" valign="top"
                background="images/main_bj.jpg" bgcolor="#FFFFFF"
                style="padding:5px; ">
                <div style="height:290px; overflow:hidden" id="content">聊天内容</div></td>
        </tr>
    </table>
    <table width="778" height="95" border="0" align="center"
        cellpadding="0" cellspacing="0" bordercolor="#D6D3CE"
        background="images/bottom.jpg">

        <form action="" id="form1" name="form1" method="post">
            <input type="hidden" name="method" value="sendMessage"/>
            <tr>
                <td height="30" align="left">&nbsp;</td>
                <td height="37" align="left">
                <input name="from" type="hidden" value="${existUser.username}">[${existUser.username} ]对 
                <input name="to" type="text" value="" size="35" readonly="readonly"> 表情 
                <select name="face" class="wenbenkuang">

                        <option value="无精打采的">无精打采的</option>
                </select> 说:</td>
                <td width="189" align="left">&nbsp;&nbsp;字体颜色: <select
                    name="color" size="1" class="wenbenkuang" id="select">
                        <option selected>默认颜色</option>
                        <option style="color:#999999" value="999999">烟雨蒙蒙</option>
                </select>
                </td>
                <td width="19" align="left"><input name="scrollScreen"
                    type="checkbox" class="noborder" id="scrollScreen"
                    onClick="checkScrollScreen()" value="1" checked>
                </td>
            </tr>
            <tr>
                <td width="21" height="30" align="left">&nbsp;</td>
                <td width="549" align="left">
                <input name="content" type="text" size="70"
                    onKeyDown="if(event.keyCode==13 && event.ctrlKey){send();}">
                    <input name="Submit2" type="button" class="btn_grey" value="发送"
                    onClick="send()">
                </td>
                <td align="right"><input name="button_exit" type="button"
                    class="btn_grey" value="退出聊天室" onClick="exit()">
                </td>
                <td align="center">&nbsp;</td>
            </tr>
            <tr>
                <td height="30" align="left">&nbsp;</td>
                <td align="center">&nbsp;</td>
            </tr>
        </form>
    </table>
</body>
</html>
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3条回答 默认 最新

  • dashicaineng
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  • u013254183
    老铁咖啡 2020-01-09 09:39

    ${ msg }是EL表达式取值
    用于简化在JSP中取值操作。el表达式本质上是调用了get方法。属性名要和get方法名保持一致。

    a标签使用href超链接标跳转
    window.location = "main.jsp"也可以跳转

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  • weixin_43970782
    成岳 2020-01-09 11:00

    ${ msg } 是request.setAttribute("msg", "msg的值");

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