JSP页面使用include指令出现 Duplicate local variable basePath

现有三个页面 " include.jsp " " a.jsp " " b.jsp "

页面代码如下

首先是a.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

<%out.println("I am a.jsp"); %>

b.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

<%out.println("I am b.jsp"); %>

include.jsp

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<%

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">

    -->

  </head>

  <body>

    <%@ include file="a.jsp" %>  
/*此处报错 
- Duplicate local variable path
- Duplicate local variable basePath
- Duplicate local variable path
*/

    <jsp:include page="b.jsp"></jsp:include>

  </body>

</html>

但是把

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

<base href="<%=basePath%>">

这两段代码删除就不会报错了

查看网上资料后了解到：include元素指令的作用发生在转换阶段，它会把a.jsp的代码包含进index.jsp；include动作指令的作用发生在执行阶段，它不会把b.jsp的代码包含到index.jsp中，而是在执行时向b.jsp发出请求，把得到的结果包含到index.jsp中。因此，查看a.jsp的源代码，发现其中有定义path，basePath变量，既然是包含源代码，那么就会和index.jsp中定义的path，basePath变量重复，这就是之前的错误提示表达的意思。

巴特西

JSP页面使用include指令出现 Duplicate local variable basePath

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