jsp自定义标签实现比较两个数值的大小

最新推荐文章于 2023-12-29 18:59:51 发布

iteye_18341

最新推荐文章于 2023-12-29 18:59:51 发布

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分类专栏： web技术文章标签： javascript java ViewUI

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这篇博客展示了如何在JSP中自定义标签`<my2:maxVal>`来比较两个数字并输出较大的值。通过Java代码实现`MyMaxVal`类，该类继承自`SimpleTag`接口，根据传入的`num1`和`num2`属性判断大小并打印结果。在HTML中使用自定义标签，比较数字123和889，最终输出889大于123。

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jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib uri="http://www.cgmcc.com/jsp/mytag" prefix="my" %>

<%@ taglib uri="http://www.cgmcc.com/jsp/mytag2" prefix="my2" %>
<%
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 'comparedata.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>

<my2:maxVal num2="123" num1="889"/>
</body>
</html>

java
package com.cgm.tldtest;

import java.io.IOException;

import javax.servlet.jsp.JspContext;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.JspFragment;
import javax.servlet.jsp.tagext.JspTag;
import javax.servlet.jsp.tagext.SimpleTag;

public class MyMaxVal implements SimpleTag {

private PageContext pageContext;

private Integer num1;

private Integer num2;

public Integer getNum1() {
return num1;
}

public void setNum1(Integer num1) {
this.num1 = num1;
}

public Integer getNum2() {
return num2;
}

public void setNum2(Integer num2) {
this.num2 = num2;
}

public void doTag() throws JspException, IOException {

if (num1>num2) {
pageContext.getOut().print(num1+"大于"+num2);
}else{

pageContext.getOut().print(num1+"小于或者等译"+num2);
}

}

public JspTag getParent() {

return null;
}

public void setJspBody(JspFragment jspBody) {

}

public void setJspContext(JspContext pc) {
this.pageContext=(PageContext) pc;

}

public void setParent(JspTag parent) {

}

}

tld

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">

<tlib-version>1.3</tlib-version>
<short-name>my3</short-name>
<uri>http://www.cgmcc.com/jsp/readfile</uri>
<tag>
<name>readFile</name>

<tag-class>com.cgm.readFile.TagReadFile</tag-class>
<body-content>empty</body-content>
<attribute>
<name>file</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<type>java.lang.String</type>
</attribute>

</tag>

</taglib>