Struts的Empty和Present等标签
对Struts中的Empty和Present等标签做下测试（具体过程可以参见尚学堂的视频）
前提：好像必须要导入struts的国际化标签，有待验证。
第一步：添加EmptyPresentTestAction类
package com.bjsxt.struts;
/**
* 测试empty,notEmpty,present,notPresent
*/
public class EmptyPresentTestAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
request.setAttribute("attr1", null);
request.setAttribute("attr2", "");
request.setAttribute("attr3", new ArrayList());
return mapping.findForward("success");
}
}
第二步：添加测试的jsp页面（emptypresent.jsp）
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<%@ taglib prefix="logic" uri="http://struts.apache.org/tags-logic"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030">
<title>测试empty,notEmpty,present,notPresent</title>
</head>
<body>
<h1>测试empty,notEmpty,present,notPresent</h1>
<hr>
<logic:empty name="attr1">
attr1为空<br>
</logic:empty>
<logic:notEmpty name="attr1">
attr1不为空<br>
</logic:notEmpty>
<logic:present name="attr1">
attr1存在<br>
</logic:present>
<logic:notPresent name="attr1">
attr1不存在<br>
</logic:notPresent>
<p>
<logic:empty name="attr2">
attr2为空<br>
</logic:empty>
<logic:notEmpty name="attr2">
attr2不为空<br>
</logic:notEmpty>
<logic:present name="attr2">
attr2存在<br>
</logic:present>
<logic:notPresent name="attr2">
attr2不存在<br>
</logic:notPresent>
<p>
<logic:empty name="attr3">
attr3为空<br>
</logic:empty>
<logic:notEmpty name="attr3">
attr3不为空<br>
</logic:notEmpty>
<logic:present name="attr3">
attr3存在<br>
</logic:present>
<logic:notPresent name="attr3">
attr3不存在<br>
</logic:notPresent>
</body>
</html>
第三步：显示出来的结果如下：
