Posted on 2007-06-26 20:04
chenweicai 阅读(288)
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步一：定义标签
步二：创建标签库描述器TLD diagnostics.tld, 将它放在WEB-INF目录下的tlds文件夹下，diagnostics.tld如下：
<?xml version="1.0"?>
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.1</jspversion>
<shortname>diag</shortname>
<tag>
<name>getWebServer</name>
<tagclass>servlet.GetWebServerTag</tagclass>
<bodycontent>empty</bodycontent>
</tag>
</taglib>
步三：编写标签处理器 GetServerTag.java
package servlet;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;
public class GetWebServerTag extends TagSupport {
@Override
public int doStartTag() throws JspException {
try{
// get the request object from the page context
HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
// Request information form the web server
URL url = new URL("http", request.getServerName(), request.getServerPort(), "/");
URLConnection con = url.openConnection();
((HttpURLConnection)con).setRequestMethod("OPTIONS");
String webserver = con.getHeaderField("server");
// write it to the output stream
JspWriter out = pageContext.getOut();
out.print(webserver);
}catch (IOException e)
{
throw new JspException(e.getMessage());
}
return SKIP_BODY;
}
}
步四： 编写WEB.xml文件
加入：
<jsp-config>
<taglib>
<taglib-uri>diagnostics</taglib-uri>
<taglib-location>/WEB-INF/tlds/diagnostics.tld</taglib-location>
</taglib>
</jsp-config>
步五：编写jsp页面，将标签并入该JSP页面
<%@ taglib prefix="diag" uri="diagnostics"%>
<html>
<head>
<title>Basci Example of a Custom Tag</title>
</head>
<body>
<H3>Basci Example of a Custom Tag</H3>
The web server is <diag:getWebServer/>
</body>
</html>
OK , so much so this ,
wish you success
<注： 注意红色的地方要一致哦>