js遍历map(js遍历map对象)

Posted 2023-04-03 叶涛网站推广优化

javascript怎么遍历map

var map = new HashMap();
map.put(a,1);
map.put(b,2);
遍历：
var key = map.keySet();
for (var i in key)
 alert(map.get(key[i]));
｝
注：js 中使用map，要先导入一个HashMap.js文件 
没要求，引入这个文件之后，可以直接使用hashmap了var map = 'a': 'aaaaa','b': 'bbbbb';for(var k in map)alert(map[k]);可以使用jquery中的each()函数。
$.each(obj, function(i) 
alert(obj[i]);
);  
function 也可以写为function(key,value)
 
key，value 就是map的key, valuejavascript中没有什么map

只有对象和数组可以遍历//你的JSON对象

var o =

foo:"bar",

arr:[1,2,3],

subo:

foo2:"bar2"

//处理每一项的键和值的函数

function process(key,value)

document.body.innerhtml += key + " : " + value + "
";

//遍历函数

function traverse(o,func)

for (i in o)

func.apply(this,[i,o[i]]);

if (typeof(o[i])=="object")

//递归

traverse(o[i],func);

//现在开始遍历

traverse(o, process);

jsp页面如何对map集合遍历

MapAction.java

Java代码

package com.zx.demo.action;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.opensymphony.xwork2.ActionSupport;

import com.zx.demo.model.Product;

import com.zx.demo.model.Student;

public class MapAction extends ActionSupport

private Map map;

private Map studentMap;

private Map arrayMap;

private Map > listMap;

public String testMap()

map=new HashMap ();

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

map.put("2", "two");

studentMap=new HashMap ();

studentMap.put("student1",new Student(new Long(1),"20034140201","张三1","男",25));

studentMap.put("student2",new Student(new Long(2),"20034140202","张三2","女",26));

studentMap.put("student3",new Student(new Long(3),"20034140202","张三3","男",27));

arrayMap=new HashMap ();

arrayMap.put("arr1", new String[]"1","2003401","leejie","male","20");

arrayMap.put("arr2", new String[]"2","2003402","huanglie","male","25");

arrayMap.put("arr3", new String[]"3","2003403","lixiaoning","male","21");

listMap=new HashMap >();

List list1=new ArrayList ();

list1.add(new Student(new Long(1),"20034140201","张三1","男",25));

list1.add(new Student(new Long(2),"20034140202","张三2","男",25));

list1.add(new Student(new Long(3),"20034140203","张三3","男",25));

listMap.put("class1", list1);

List list2=new ArrayList ();

list2.add(new Student(new Long(1),"20034140301","李四1","男",20));

list2.add(new Student(new Long(2),"20034140302","李四2","男",21));

list2.add(new Student(new Long(3),"20034140303","李四3","男",22));

list2.add(new Student(new Long(4),"20034140304","李四4","男",23));

listMap.put("class2", list2);

return SUCCESS;

public Map getMap()

return map;

public void setMap(Map map)

this.map = map;

public Map getStudentMap()

return studentMap;

public void setStudentMap(Map studentMap)

this.studentMap = studentMap;

public Map getArrayMap()

return arrayMap;

public void setArrayMap(Map arrayMap)

this.arrayMap = arrayMap;

public Map > getListMap()

return listMap;

public void setListMap(Map > listMap)

this.listMap = listMap;

2.testMap.jsp

Java代码

1.map中的value为String字符串

key:

value:

******************************************

2.map中的value为Student对象

key=value	ID	num	name	sex	age

3.map中的value为String数组

key=value	ID	num	name	sex	age

4.map中的value为list集合

class	ID	num	name	sex	age

$item.key中的key的值是你定义的一个班级Class对象，它不是可遍历的对象。

$var.name

$item.key.name

JS几种遍历方式比较

几种遍历方式比较

• for of 循环不仅支持数组、大多数伪数组对象，也支持字符串遍历，此外还支持 Map 和 Set 对象遍历。

• for in 循环可以遍历字符串、对象、数组，不能遍历 Set/Map

• forEach 循环不能遍历字符串、对象,可以遍历 Set/Map