Hash

import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;


public class HashDemo {
public static void main(String[] args){
    HashMap<String,Integer> hs=new HashMap<String,Integer>();
    hs.put("a",1);
    hs.put("b", 2);
    hs.put("c", 3);
    /*Collection collection=hs.values();
    Iterator iter=collection.iterator();
    while(iter.hasNext()){
        //System.out.println(iter.next());
    }*/
    //也可以用for循环
    for( Integer value:hs.values()){
        System.out.println(value);
    }
}
}

import java.util.EnumMap;
import java.util.Map;

enum Action {True_Left,True_Right,Shoot}
public class TreeMap {
public static void main(String[] args)
{
    Map<Action,String> map=new EnumMap<Action,String>(Action.class);
    map.put(Action.True_Left, "向左转");
    map.put(Action.True_Right,"向右转");
    map.put(Action.Shoot, "射击");
    for(Action action:Action.values()){
        System.out.println(action);
    }
    
    
}
}