TreeMap ,Hashtable,linkedHashMap的排序

import java.util.Hashtable;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;


public class list {
  public static void main(String []args){
 
//   Map mm = new TreeMap();//TreeMap 从小排到大
//   Map mm = new Hashtable();//从大排到小
  Map mm = new LinkedHashMap();//按照你自己的排序顺序来定义
  mm.put(8,"888888");
  mm.put(1, "123");
  mm.put(5,"5555");
  mm.put(4, "4444");
  mm.put(9,"9");
  Set set = mm.keySet();
  for(Object key : set){
  System.out.println(mm.get(key));
  }
//   Iterator it  = mm.keySet().iterator();
//   while(it.hasNext()){
//   System.out.println(it.next());
//   }
//   Iterator it2 = mm.entrySet().iterator();
//   while(it2.hasNext()){
//   System.out.println(it2.next());
//  
//   }
     
  }
}