JSP带有属性的自定义标签

2018-05-28

新建HelloWelTag类

如何添加jsp-api.jar包

HelloWelTag类详细代码

package bid.zhazhapan.fims.tag;
import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
public class HelloWelTag extends TagSupport {
	private String name;// 定义对应标签的属性
	// 通过set方法从页面获得name的属性值
	public void setName(String name) {
		this.name = name;
	}
	// 覆盖doEndTag()方法
	public int doEndTag() throws JspException {
		try {
			// 通过pageContext对象获得页面隐式对象out，向客户端输出结果
			pageContext.getOut().write("Welcome " + name);
		} catch (IOException e) {
			e.printStackTrace();
			new JspException("IO Error" + e.getMessage());
		}
		return this.EVAL_PAGE;
	}
}

如何配置xml

<!-- xml详细内容 -->
<?xml version="1.0" encoding="UTF-8"?>
<javaee:taglib version="2.1" xmlns:javaee="http://java.sun.com/xml/ns/javaee" xmlns:xml="http://www.w3.org/XML/1998/namespace" 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-jsptaglibrary_2_1.xsd ">
  <javaee:tlib-version>1.0</javaee:tlib-version>
  <javaee:short-name>demo</javaee:short-name>
  <javaee:uri>/demo</javaee:uri>
  <javaee:tag>
  	<javaee:name>welcome</javaee:name>
  	<javaee:tag-class>bid.zhazhapan.fims.tag.HelloWelTag</javaee:tag-class>
  	<javaee:body-content>empty</javaee:body-content>
  	<javaee:attribute>
  		<javaee:name>name</javaee:name><!-- 属性名称 -->
  		<javaee:required>true</javaee:required><!-- 属性是否必须 -->
  		<javaee:rtexprvalue>true</javaee:rtexprvalue><!-- 属性是否可以添加动态代码（jsp脚本） -->
  	</javaee:attribute>
  </javaee:tag>
</javaee:taglib>

新建test.jsp来测试标签

<!-- test.jsp详细代码 -->
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ taglib uri="WEB-INF/tlds/mytag.tld" prefix="mytag" %>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<mytag:welcome name="<%=\"Tony\" %>" />
</body>
</html>
<!-- 输出结果：Welcome Tony -->