定义switch
package tag;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.TagSupport;
public
Switch extends TagSupport { private boolean subtagsuccess;
public Switch
{ subtagsuccess=false;a
}
/*
* 当遇到switch标签时
所有
子标签都不执行
* @see javax.servlet.jsp.tagext.TagSupport#doStartTag
*/
public
doStartTagthrows JspTagException{ subtagsuccess=false;
EVAL_BODY_INCLUDE; }
/*
* 该思路方法有子标签
表示是否可以执行自身标签 */
public synchronized boolean getpermission
{ (!subtagsuccess); }
public synchronized boolean subtagsuccessed
{ subtagsuccess=true; }
/*
* 销毁到该思路方法
* @see javax.servlet.jsp.tagext.TagSupport#release
*/
public void release
{ subtagsuccess=false;
}
}
定义
package tag;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;
public
Case extends TagSupport{ private boolean cond;
public Case
{ cond=false;
}
public void release
{ cond=false;
}
public void
Cond(boolean cond){ this.cond=cond;
}
public
doStartTagthrows JspTagException{ Tag parse=getParent
; /*
* 判断是否可以执行本身
*/
(!((Switch)parse).getpermission) SKIP_BODY; /*
* 如果条件是真
通知父类表示已经有了
个符合条件 * 否则
忽略标签体 */
(cond){ ((Switch)parse).subtagsuccessed
; EVAL_BODY_INCLUDE; }
{ SKIP_BODY; }
}
}
定义default
package tag;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;
public
Default extends TagSupport { public void Default
{ }
public
doStartTagthrows JspTagException{ //
0; Tag default
=getPareant; (!((Switch)default).getpermission) SKIP_BODY; ((Switch)default
).subtagsuccessed; EVAL_BODY_INCLUDE; }
}
tld文件
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE taglib
PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
"http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>1.2</jsp-version>
<
-name>swicth</-name> <display-name>simpley swicth</display-name>
<description>simple jsp tag3 </description>
<tag>
<name>swicth</name>
<tag-
>tag.Switch</tag-> <body-content>jsp</body-content>
<description>simple jsp tag 03</description>
</tag>
<tag>
<name>
</name> <tag-
>tag.Case</tag-> <body-content>jsp</body-content>
<description>simple jsp tag 03</description>
<attribute>
<name>cond</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<!-- true表示可以用接受表达式；false:反的
--> </attribute>
</tag>
<tag>
<name>default</name>
<tag-
>tag.Default</tag-> <body-content>jsp</body-content>
<description>simple jsp tag 03</description>
</tag>
</taglib>
webx.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<jsp-config>
<taglib>
<taglib-uri>/jsptag3.tld</taglib-uri>
<taglib-location>/WEB-INF/jsptag3.tld</taglib-location>
</taglib>
</jsp-config>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
定义jsp页面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="/jsptag3.tld" prefix="djl" %>
<%
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 'index.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">
-->
a
</head>
<body>
<% String name=request.getParameter("name"); %>
<djl:swicth>
<djl:
cond="<%=name.equals("dengjianli")%>"> <%out.pr
(" 您输入是:dengjianli"); %> </djl:
> <djl:
cond="<%=name.equals("dengxiaoping") %>"> <%out.pr
(" 您输入是:dengxiaoping"); %> </djl:
> <djl:default>
<%out.pr
ln("没有您合适输入数据！"); %> </djl:default>
</djl:swicth>
</body>
</html>
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