键值key排序

http://qixiaopeng.iteye.com/blog/411537

 

Map map = new HashMap(); 
map.put("4",   "a"); 
map.put("2",   "b"); 
map.put("1",   "c"); 
map.put("3",   "d");
 
第一种方法：

Object[] key = map.keySet().toArray(); Arrays.sort(key); for(int i = 0; i<key.length; i++) { System.out.println(map.get(key[i])); }

第二种方法：

1. List arrayList = new ArrayList(map.entrySet()); 2. 3. Collections.sort(arrayList, new Comparator() 4. { 5. public int compare(Object arg1, Object arg2) 6. { 7. Map.Entry obj1 = (Map.Entry) arg1; 8. Map.Entry obj2 = (Map.Entry) arg2; 9. return (obj1.getKey()).toString().compareTo(obj2.getKey()); 10. } 11. }); 12. //将HASHMAP中的数据排序 13. for (Iterator iter = arrayList.iterator(); iter.hasNext();) 14. { 15. Map.Entry entry = (Map.Entry)iter.next(); 16. String key = (String)entry.getKey(); 17. System.out.println(map.get(key)); 18. }

Object[] key =  map.keySet().toArray();  
Arrays.sort(key);  

for(int i = 0; i<key.length; i++)
{  
     System.out.println(map.get(key[i]));  
}