Hashmap 通过对VALUE排序

对KEY的排序比较简单 直接用treeMap就可以,通过构造方式或者是KEY值类实现Comparable 接口也可以

@Test
		public void TestThree()
		{
			//对MAP的VALUE值进行排序 简单来说就在TREEMAP对KEY排序的基础上 通过KEY拿VALUE 然后在进行排序
				HashMap<String,Integer> hashmap = new HashMap<String,Integer>();
				hashmap.put("two", 2);
				hashmap.put("one", 1);
				hashmap.put("aa", 3);
			//注入排序MAP
			HashMapSort hashmapsort  = 	 new HashMapSort(hashmap);
			
			TreeMap<String,Integer> sortaftertreemap = new TreeMap<String,Integer>(hashmapsort);
			sortaftertreemap.putAll(hashmap);
			
			Set<Entry<String,Integer>> treehampset =  hashmap.entrySet();
			Iterator<Entry<String,Integer>>  treemapiterator  = treehampset.iterator();
			while(treemapiterator.hasNext())
			{
				Entry<String,Integer>  hasp = treemapiterator.next();
				System.out.println("treemap3-------"+hasp.getKey());
				System.out.println("treemap3-------"+hasp.getValue());
			}
			
			sortaftertreemap.put("fs", 411);
			Set<Entry<String,Integer>> sortaftertreemapset =  sortaftertreemap.entrySet();
			Iterator<Entry<String,Integer>>  sortaftertreemapsetiterator  = sortaftertreemapset.iterator();
			while(sortaftertreemapsetiterator.hasNext())
			{
				Entry<String,Integer>  hasp = sortaftertreemapsetiterator.next();
				System.out.println("treemapaftersort-------"+hasp.getKey());
				System.out.println("treemapaftersort-------"+hasp.getValue());
			}
			
			HashMap<String,Integer> hashmap2 = new HashMap<String,Integer>(sortaftertreemap);
			printMap(hashmap2);
			//还有一种是变成LIST 然后通过COLLECTIONS.SORT(LIST,Comparator) 进行排序 这个比较常见 这个地方就不写了
			
		}

//排序类

class HashMapSort implements Comparator<String>
		{
			private Map<String,Integer> map = null;
			
			public HashMapSort(Map<String,Integer> map)
			{
				this.map = map;
			}
			
			public int compare(String o1, String o2) {
				// TODO Auto-generated method stub	
				if(!map.containsKey(o1)||!map.containsKey(o2))
				{
					return o1.hashCode() - o2.hashCode();
				}			
				return map.get(o1)- map.get(o2);
			}
			
		}