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