几乎相同的 deal.jsp 代码（index.jsp不变），在IDEA相同项目运行，结果却不同，实在想不出来

时间 2019-11-12

标签几乎相同 deal.jsp deal jsp 代码 index.jsp index 不变 idea 项目运行结果却不实在出来栏目 JSP 繁體版

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目录css

主要问题

几乎相同的 deal.jsp 代码（index.jsp不变），在IDEA相同项目相互运行，结果却不同，实在想不出来html

主要项目

对应的IDEA JSP项目:6.9_2.zipjava

index.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>显示历史、显示添加留言功能</title>
    <link rel="stylesheet" type="text/css" href="word_index.css" />

    <script language="JavaScript">
        function ifNull(form_Msg){
            var userName = form_Msg.upload_UserName.value;
            var userMsg = form_Msg.upload_UserMsg.value;
            if (userName === "") {
                alert("留言人不能为空");
                form_Msg.upload_UserName.focus();
                return false;
            }
            if (userMsg === "") {
                alert("留言内容不能为空");
                form_Msg.upload_UserMsg.focus();
                return false;
            }
        }
    </script>
</head>
<body>
<span class="word_Msg">留言板</span><br><br>
<%

    if (session.isNew()){
        int number_person_index = 0;
        session.setAttribute("number_person",number_person_index);
    }

    int i;
    String[] message_index = (String[])session.getAttribute("message");
    int num = Integer.parseInt(session.getAttribute("number_person").toString());
    if (num != 0) {
        out.println("123213132");
        out.println("number_person: " + num + "<br><br>");
        for (i=0; i < num; i++) {
            out.println(message_index[i]);
        }
    }
%>
<br><hr>

<form action="deal.jsp" id="form_UploadMassage" name="form_UploadMassage" method="post" onSubmit="return ifNull(form_UploadMassage)">
    <span class="word_Msg">添加留言区域</span><br>
    留言人：<input type="text" id="upload_UserName" name="upload_UserName" title="留言人">
    留言内容：<textarea id="upload_UserMsg" name="upload_UserMsg" title="留言内容"></textarea>
    <input name="Submit" type="submit" value="提交留言">
    <input name="Submit2" type="reset" value="重置">
</form>
</body>
</html>

deal.jsp（正确可运行）:

<%@ page language="java" contentType="text/html; charset=utf-8"
         pageEncoding="utf-8"%>
<%
    request.setCharacterEncoding("utf-8");
    String userName_deal=request.getParameter("upload_UserName");   //获取留言人
    String userMsg_deal=request.getParameter("upload_UserMsg"); //获取留言内容
    String message_add="["+userName_deal+"]说："+userMsg_deal+"<br>"; //组合留言信息

    int i;
    int num = Integer.parseInt(session.getAttribute("number_person").toString());
    int num_add = num+1;
    String[] message_old = (String[])session.getAttribute("message");
    String[] message_new = new String[num_add+1];

    if(session.getAttribute("number_person")!=null){
        if (num > 0) {
            for (i=0; i<num; i++) {
                message_new[i] = message_old[i];
            }
        }
        message_new[num_add-1] = message_add;
    }
    session.setAttribute("number_person",num_add);
    session.setAttribute("message",message_new);    //将留言信息保存到session中
    response.sendRedirect("index.jsp");
%>

deal.jsp（错误不可运行）:

<%@ page language="java" contentType="text/html; charset=utf-8"
         pageEncoding="utf-8"%>
<%
    request.setCharacterEncoding("utf-8");
    String userName_deal = request.getParameter("upload_UserName");
    String userMsg_deal = request.getParameter("upload_UserMsg");
    String message_add = "["+userName_deal+"]说："+userMsg_deal+"<br>";   //组合留言信息

    int i;
    int num = Integer.parseInt(session.getAttribute("number_person").toString());
    int num_add = num+1;
    String[] message_old = (String[])session.getAttribute("message");
    String[] message_new = new String[num_add+1];

    if (session.getAttribute("number_person")!=null) {
        if (num > 0) {
            for (i=0; i<num; i++) {
                message_new[i] = message_old[i];
            }
        }
        message_new[num_add-1] = message_add;
    }
    session.setAttribute("number_person",num_add);
    session.setAttribute("massage",message_new);
    response.sendRedirect("index.jsp");
%>

几乎相同的 deal.jsp 代码（index.jsp不变），在IDEA相同项目运行，结果却不同，实在想不出来

主要问题

主要项目

index.jsp:

deal.jsp（正确可运行）:

deal.jsp（错误不可运行）:

错误的代码运行图片：

可运行的代码运行图片