jsp自定义标签

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必须：一个tag类，一个tld;

第一步：
package com.sshcms.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;

/**
*package_name com.sshcms.tag
*file_name AuthorityPermissionTag.java
*author zbw
*date 2012-3-27上午09:26:27
*/
public class AuthorityPermissionTag extends TagSupport {

private String param;

public String getParam() {
return param;
}

public void setParam(String param) {
this.param = param;
}

@Override
public int doStartTag() throws JspException {
// TODO Auto-generated method stub
HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
JspWriter out = pageContext.getOut();
try {
if("1".equals(param))
out.print("Hello World");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return SKIP_BODY;
}
}

第二步：tld 文件，新建在WEB-INF下；/WEB-INF/tld/authority-permission.tld
<?xml version="1.0" encoding="ISO-8859-1"?>
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>1.2</jsp-version>

<tag>
<name>authority</name>
<tag-class>com.sshcms.tag.AuthorityPermissionTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>param</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>

</taglib>

tld的基本属性：

第三步：在web.xml配置该标签
<jsp-config>
<taglib>
<taglib-uri>/UserTag-Authority</taglib-uri>
<taglib-location>/WEB-INF/tld/authority-permission.tld</taglib-location>
</taglib>
</jsp-config>

第四布：调用；
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%@taglib prefix="m" uri="/UserTag-Authority" %>
<%
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 'tagTest.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">


</head>

<body>
<m:authority param="1"/>
</body>
</html>

shortname：指定Tag Library默认的前缀名(prefix)
uri：设定Tag Library的惟一访问表示符
标签元素用来定义一个标签，它的常见属性有：
name：设定Tag的名字
tagclass：设定Tag的处理类
bodycontent：设定标签的主体(body)内容
empty：表示标签中没有body
JSP：表示标签的body中可以加入JSP程序代码
tagdependent：表示标签中的内容由标签自己去处理
标签属性元素用来定义标签的属性，它的常见属性有：
A.name：属性名称
B.required：属性是否必需的，默认为false
rtexprvalue：属性值是否可以为request-time表达式，也就是类似于<%=…%>的表达式

运行效果：