自定义jstl标签用法案例

07820170914
jstl自定义标签：主要用于移除Jsp页面中的java代码

1、编写一个类，继承SimpleTagSupport[类属性与配置在tld中的属性参数一致，添加set、get方法]

2、重写doTage(标签的核心方法，输出标签的内容)

3、编写一个tld文件(描述标签的属性[标签名、对应的类、对应的uri...])package com.tiger.tag;

import java.io.IOException;
import java.util.Map;
import java.util.Set;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
 * 遍历集合,nobody
 * @author tiger
 * @time 2017年9月13日
 */
public class MySelect extends SimpleTagSupport{

	//设置参数,与.tld文件中attribute中的name一致
	private Map map;
	
	private String path;

	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public Map getMap() {
		return map;
	}

	public void setMap(Map map) {
		this.map = map;
	}
	
	@Override
	public void doTag() throws JspException, IOException  {
		//内置一个pageContext对象，它里面是封装了9个隐式对象
		StringBuffer htmlBuffer=new StringBuffer();
		//遍历集合元素
		htmlBuffer.append("
");
		Set set = map.keySet();
		for (Object key : set) {
			htmlBuffer.append("");
			htmlBuffer.append(map.get(key));
			htmlBuffer.append("
");
		}
		htmlBuffer.append(" ");
		getJspContext().getOut().println(htmlBuffer.toString());
	}
}

package com.tiger.tag;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
 * 遍历集合,hasbody
 * @author tiger
 * @time 2017年9月13日
 */
public class MySelectBody extends SimpleTagSupport{

	//设置参数,与.tld文件中attribute中的name一致
	private Map map;
	private String path;
	
	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public Map getMap() {
		return map;
	}

	public void setMap(Map map) {
		this.map = map;
	}
	
	@Override
	public void doTag() throws JspException, IOException  {
		JspWriter out = getJspContext().getOut();
		out.println("
");
		Iterator it = map.keySet().iterator();
		while (it.hasNext()) {
			getJspContext().setAttribute("map", map.get(it.next()));
			getJspBody().invoke(null);
		}
		out.println("");
	}
}





	JSTL 1.1 core library
	JSTL core
	1.1
	tiger

	http://www.tiger.com/tigertag

	
	
		
		table
		
		com.tiger.tag.MyTable
		
		empty
		
			collection
			
			true
			
			true
		
	

	
	
		
		select
		
		com.tiger.tag.MySelect
		
		empty
		
			map
			
			true
			
			true
		
		
			path
			
			true
			
			true
		
	

	
	
		
		selectbody
		
		com.tiger.tag.MySelectBody
		
		scriptless
		
			map
			
			true
			
			true
		
		
			path
			
			true
			
			true
		
	
<%@page import="java.util.HashMap"%>
<%@page import="java.util.Map"%>
<%@page import="java.util.Collection"%>
<%@page import="java.util.Collections"%>
<%@page import="java.util.ArrayList"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>

<%@ taglib prefix="my" uri="http://www.tiger.com/tigertag"%>





	<%
		Map map = new HashMap();
		map.put("001", "tiger");
		map.put("002", "hello");
		map.put("003", "xixi");
		pageContext.setAttribute("map", map);
	%>
	




<%@page import="java.util.HashMap"%>
<%@page import="java.util.Map"%>
<%@page import="java.util.Collection"%>
<%@page import="java.util.Collections"%>
<%@page import="java.util.ArrayList"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>

<%@ taglib prefix="my" uri="http://www.tiger.com/tigertag"%>








	<%
		Map map = new HashMap();
		map.put("001", "body");
		map.put("002", "呵呵");
		map.put("003", "嘻嘻");
		pageContext.setAttribute("map", map);
	%>
	
		${map}