java map 的用法

import java.util.*;
public class MapKeyWord {
public static void main(String[] args) {
Map m1 = new HashMap();
Map m2 = new TreeMap();

m1.put("one",new Integer(1));
m2.put("two",new Integer(2));

m2.put("A",new Integer(1));
System.out.println(m1.size());
System.out.println(m2.size());

System.out.println(m1.containsKey("one"));
System.out.println(m1.containsValue(1));

int i = ((Integer)m1.get("one")).intValue();
System.out.println("i = " + i);

Map m3 = new HashMap(m1);
m3.putAll(m2);
System.out.println(m3);
}
}