encoding/path可能引起无数奇怪的问题

时间:2020-12-07 00:30:44

例如如下代码:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://www.mldn.cn/jst/core"%>
<%@ taglib prefix="x" uri="http://www.mldn.cn/jst/x"%>
<!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>Insert title here</title>
</head>    
<body>
    <c:import var="add" url="/ch13/address.xml" charEncoding="GBK"/>
    <x:parse var="addressXml" doc="${add}"/>
    <x:choose>
        <x:when select="$addressXml//name/@id='lxh'">
            <h3>编号是lxh的名称是:<x:out select="$addressXml/addresslist/linkman/name"/></h3>
        </x:when>
        <x:otherwise>
            <h3>啥也不是了!</h3>
        </x:otherwise>
    </x:choose>
</body>
</html>

运行的时候出现这种异常:

七月 15, 2013 8:40:34 上午 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet jsp threw exception
org.xml.sax.SAXParseException; systemId: jstl:; lineNumber: 6; columnNumber: 4; 元素类型 "name" 必须由匹配的结束标记 "</name>" 终止。
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source)
你查啥去?没得查,就仅仅是因为你的c:import使用了GBK,而页面以及address.xml都是用的UTF-8!

又比如昨天,我遇到这个问题

HTTP Status 500 - javax.servlet.ServletException: javax.servlet.jsp.JspException: org.xml.sax.SAXParseException; systemId: jstl:; lineNumber: 1; columnNumber: 1; 前言中不允许有内容。

代码是这样的:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://www.mldn.cn/jst/core"%>
<%@ taglib prefix="x" uri="http://www.mldn.cn/jst/x"%>
<!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>Insert title here</title>
</head>    
<body>
    <c:import var="add" url="/ch12/address.xml" charEncoding="UTF-8"/>
    <x:parse var="addressXml" doc="${add}"/>
    <h3>姓名:<x:out select="$addressXml/addresslist/linkman/name"/>(编号:<x:out select="$addressXml/addresslist/linkman/name/@id"/></h3>
    <h3>邮箱:<x:out select="$addressXml/addresslist/linkman/email"/></h3>
</body>
</html>

最后查明原因,仅仅是因为c:import的url中,ch12应该换为才ch13!仅仅因为我把路径写错了而已,但是它却报了个跟路径貌似毫无关系的exception!