jsp遍历所有数据标签与转义标签

1. 开发遍历所有类型数据的标签

[java]
标签处理类：

package com.csdn.web.example;



import java.io.IOException;

import java.lang.reflect.Array;

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;



import javax.servlet.jsp.JspException;

import javax.servlet.jsp.tagext.SimpleTagSupport;



publicclass ForEachAll extends SimpleTagSupport{



 private Collection collection;



 private String var;

 private Object items;



 publicvoid setVar(String var) {

 this.var = var;

 }



 publicvoid setItems(Object items) {

 this.items = items;

 }



 @Override

 publicvoid doTag() throws JspException, IOException {

 //判断是否是Map 下面的三个判断可以在doTage（）方法中也可以在setItems（）方法中

 if(itemsinstanceof Map){

 //这里要把jsp页面传进来的属性强转为Map类型，不能new HashMap

 Map map = (Map) items;

 collection = map.entrySet();

 }

 //判断是否是set、list

 if(itemsinstanceof Collection){

 collection = (Collection) items;

 }

 //判断是否是数组，各种数组

 if(items.getClass().isArray()){

 collection = new ArrayList();

 int len = Array.getLength(items);

 for(int i=0;i<len;i++){

 collection .add( Array.get(items, i));

 }



 }

 Iterator it = collection.iterator();

 while(it.hasNext()){

 Object obj = it.next();

 this.getJspContext().setAttribute(var,obj);

 this.getJspBody().invoke(null);

 }

 }



}

Jsp文件

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

<%@ taglib uri="example" prefix="example"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>



 <title>遍历各种类型数据</title>



</head>



<body>

<%

 List list = new ArrayList();

 list.add(1);

 list.add("aa");

 list.add("bb");

 list.add(2);

 request.setAttribute("list",list);

 %>

 <example:forEachAll var="str" items="${list}">

 ${ str } 

 </example:forEachAll>

 <hr>



 <%

 Map map = new HashMap();

 map.put("1","aa");

 map.put(2,"aa");

 map.put(3,"aa");

 map.put(4,"aa");

 request.setAttribute("map",map);

 %>

 <example:forEachAll items="${map}" var="map">

 ${ map.key}-------${ map.value } 

 </example:forEachAll>

 <hr>



 <%

 String[] strs = {"asd","fff","v","tt"};

 request.setAttribute("strs",strs);

 %>

 <example:forEachAll items="${strs}" var="str">${str} </example:forEachAll>

 <hr>



 <%

 int[] i = {1,2,3,4};

 request.setAttribute("i",i);

 %>

 <example:forEachAll items="${i}" var="num">${num} 

 </example:forEachAll>

 &

补充：Web开发 , Jsp ,