1： 编写一个实现Tag接口的Java类(标签处理器类)
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package
cn.gbx.web.tag;
import
java.io.IOException;
import
javax.servlet.http.HttpServletRequest;
import
javax.servlet.jsp.JspException;
import
javax.servlet.jsp.JspWriter;
import
javax.servlet.jsp.tagext.TagSupport;
public
class
ViewIpTag extends
TagSupport {
@Override
public
int
doStartTag() throws
JspException {
HttpServletRequest request = (HttpServletRequest) this.pageContext.getRequest();
JspWriter out = this.pageContext.getOut();
try
{
out.print(request.getRemoteAddr());
} catch
(IOException e) {
throw
new
RuntimeException(e);
}
return
super.doStartTag();
}
} |
2：在tld文件中对标签处理器类进行描述 tld文件的位置放在WEB-INF中（/Test2/WebRoot/WEB-INF/jsptag/gbx.tld）。 文件模式可以从tomcat中查看
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<?xml version="1.0"
encoding="UTF-8"
?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<description>A tag library exercising SimpleTag handlers.</description>
<tlib-version>1.0</tlib-version>
<short-name>SimpleTagLibrary</short-name>
<uri>http://www.gbx.com.cn</uri>
<tag>
<description>show client IP</description> <!-- 注释说明 -->
<name>viewIP</name> <!-- 配置的标签名 -->
<tag-class>cn.gbx.web.tag.ViewIpTag</tag-class>
<body-content>empty</body-content> <!-- 标签体为空 -->
</tag>
</taglib> |
3：在jsp页面利用taglib指令导入我们的tld文件的uri， 然后使用即可。
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<%@ 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 ‘1.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>
<gbx:viewIP/>
</body>
</html> |