HashMap以对象作为key

class Test
{
    public static void main(String args[])
    {
        HashMap hm = new HashMap();
        Object o = new Test1(1);
        hm.put(o, "Hello");
        System.out.println(hm.get(o));
    }
}  

class Test1
{
	private int i;	
	Test1(int i)
	{
		this.i = i;
	}
	..................
}