java集合LinkHashMap

linkHashMap集合，元素存放位置和放入的顺序一样

import java.util.HashMap;import java.util.Iterator;import java.util.LinkedHashMap;import java.util.Map;import java.util.Set;public class LinkedHashMapTest {   public static void main(String args[])  {   System.out.println("LinkedHashMap:存放顺序和放入的顺序一样");   Map<Integer,String> map = new LinkedHashMap<Integer,String>();   map.put(3, "香蕉");   map.put(2, "茄子");   map.put(1, "梨");   System.out.println(map);   //遍历: 先取key,再根据key取出value   Set<Integer> keySet=map.keySet();   Iterator<Integer> it1 =keySet.iterator();   while(it1.hasNext())   {   Object key=it1.next();   String value=map.get(key);   System.out.println("key="+key+" value="+value);   }      System.out.println("HashMap:存放顺序和放入的顺序无关");   Map<Integer,String> map1 = new  HashMap<Integer,String>();   map1.put(3, "香蕉");   map1.put(2, "茄子");   map1.put(1, "梨");   System.out.println(map1);   //遍历：for循环实现   for (Iterator<Integer> it =  map1.keySet().iterator();it.hasNext();)   {    Object key = it.next();    System.out.println("key="+key+" value="+map1.get(key));   } /*     //等价遍历方式2：   Set<Integer> keySet=map1.keySet();   Iterator<Integer> it =keySet.iterator();   while(it.hasNext())   {   Object key=it.next();   String value=map1.get(key);   System.out.println("key="+key+" value="+value);   }   */  }}

结果：

LinkedHashMap:存放顺序和放入的顺序一样
{3=香蕉, 2=茄子, 1=梨}
key=3 value=香蕉
key=2 value=茄子
key=1 value=梨
HashMap:存放顺序和放入的顺序无关
{1=梨, 2=茄子, 3=香蕉}
key=1 value=梨
key=2 value=茄子
key=3 value=香蕉