无法为 Java 中的自定义标签加载标签处理程序类
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Unable to load tag handler class for custom tag in Java
提问by Janine
I am working with custom tags in Java and I am getting an error. Let me detail below the files involved:
我正在使用 Java 中的自定义标签，但出现错误。让我在下面详细说明所涉及的文件：
My tag.tld (path is: \WEB-INF\tlds\tag.tld) has the following content:
我的tag.tld（路径是：\WEB-INF\tlds\tag.tld）有以下内容：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
"http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
<tlibversion>0.0</tlibversion>
<jspversion>1.1</jspversion>
<shortname>message</shortname>
<tag>
<description>StringReverseTag</description>
<name>string</name>
<tag-class>mytag.StringReverseTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>data</name>
<required>true</required>
</attribute>
</tag>
</taglib>
ReverseEx.jsp
ReverseEx.jsp
<%@page contentType="text/html" pageEncoding="UTF-8" language="java"%>
<!DOCTYPE html>
<%@taglib uri="/WEB-INF/tlds/tag.tld" prefix="jen" %>
<jen:string data="EARTH"/>
<html>
<head>
<title>Tag Example</title>
</head>
<body>
</body>
</html>
Helper class:
辅助类：
package chap4;
import java.io.IOException;
import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.*;
public class StringReverseTag extends SimpleTagSupport{
private String data;
public void setData(String data) {
this.data=data;
}
@Override
public void doTag() throws JspException, IOException{
JspWriter out = getJspContext().getOut();
StringBuffer sb= new StringBuffer(data);
sb.reverse();
out.print(sb);
}
}
The error I get is the following:
我得到的错误如下：
org.apache.jasper.JasperException: file: ...Struts/Struts/build/web/ReverseEx.jsp(10,0) PWC6032: Unable to load tag handler class "mytag.StringReverseTag" for tag "jen:string" org.apache.jasper.JasperException: PWC6032: Unable to load tag handler class "mytag.StringReverseTag" for tag "jen:string" ...Struts/Struts/build/web/ReverseEx.jsp(10,0) ...Struts\Struts\nbproject\build-impl.xml:924: Java returned: 1 BUILD FAILED (total time: 2 seconds)
org.apache.jasper.JasperException：文件：...Struts/Struts/build/web/ReverseEx.jsp(10,0) PWC6032：无法为标签“jen:string”加载标签处理程序类“mytag.StringReverseTag” .apache.jasper.JasperException：PWC6032：无法为标签“jen:string”加载标签处理程序类“mytag.StringReverseTag”...Struts/Struts/build/web/ReverseEx.jsp(10,0) ...Struts \Struts\nbproject\build-impl.xml:924：Java 返回：1 BUILD FAILED（总时间：2 秒）
What am I doing wrong?
我究竟做错了什么？
回答by Rami.Q
in your tag.tldfile you write:
在你的tag.tld文件中你写：
<tag-class>mytag.StringReverseTag</tag-class>
this means: your class StringReverseTagshould be in myTagpackage.
but in your code of StringReverseTagi can see that you have chap4as package!
这意味着：您的课程StringReverseTag应该在myTag包中。但在你的代码中StringReverseTag我可以看到你有一个chap4包！
to solve your problem just change:
要解决您的问题，只需更改：
<tag-class>mytag.StringReverseTag</tag-class>
to
到
<tag-class>chap4.StringReverseTag</tag-class>
