Incompatible operand types String and int
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>My JSP 'index.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">--><script type="text/javascript"> function sum(){ var form = document.getElementById("sum");alert(form);//form.method="POST";//form.action="mystruts/sum.action"; //form.submit(); var ajax = InitAjax(); alert(ajax); }function InitAjax(){ var ajax=false; try { ajax = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { ajax = new ActiveXObject("Microsoft.XMLHTTP"); } catch (E) { ajax = false; } } if (!ajax && typeof XMLHttpRequest!='undefined') { ajax = new XMLHttpRequest(); } return ajax;}function ajaxGet(){//需要进行Ajax的URL地址 var url = ""; //获取新闻显示层的位置 var show = document.getElementByIdx("show_news"); //实例化Ajax对象 var ajax = InitAjax(); //使用Get方式进行请求 ajax.open("GET", url, true); //获取执行状态 ajax.onreadystatechange = function() { //如果执行是状态正常，那么就把返回的内容赋值给上面指定的层 if (ajax.readyState == 4 && ajax.status == 200) { show.innerHTML = ajax.responseText; } } //发送空 ajax.send(null);}function ajaxPost(){//接收表单的URL地址 var url = "/"; //需要POST的值，把每个变量都通过&来联接 var postStr = "user_name="+ userName +"&user_age="+ userAge +"&user_sex="+ userSex; //实例化Ajax var ajax = InitAjax(); //通过Post方式打开连接 ajax.open("POST", url, true); //定义传输的文件HTTP头信息 ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); //发送POST数据 ajax.send(postStr); //获取执行状态 ajax.onreadystatechange = function() { //如果执行状态成功，那么就把返回信息写到指定的层里 if (ajax.readyState == 4 && ajax.status == 200) { msg.innerHTML = ajax.responseText; }}} </script></head><body><jsp:include page="test/head.jsp"></jsp:include><hr/>This is my JSP page. <br /><!-- <s:form action="mystruts/sum.action"><s:textfield name="operand1" label=" 操作数1" /><s:textfield name="operand2" label=" 操作数2" /><s:submit value="代数和" /></s:form> --><br><form action="mystruts/sum.action" id="sum"><input type="text" name="operand1" label=" 操作数1" /><input type="text" name="operand2" label=" 操作数2" /><input type="submit" value="代数和" /><input type="button" value="代数和2"/></form>${2*4 }<c:if test="${1==1}">dd</c:if><hr/><jsp:include page="test/foot.jsp"></jsp:include></body></html>报错原因：
<c:if test="${1==1}">dd</c:if>
比较内容${1==1}没有任何意义，一般解释为 变量和变量比较，或变量和常量比较，两个常量没意义，所报错，但没有影响
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