map.entrySet

Map的第一种用法
Set keys=map.keySet();
if(keys!=null)
{
    Iterator keysIterator=keys.iterator();
    while(keysIterator.hasNext())
    {
        key=keysIterator.next();
        Object  value=map.get(key);   
    }

}
    

map的第二种用法
Set entries=map.EntrySet();
if(entries!=null)
{   
    Iterator entriesIterator=entries.iterator(); 
    while(entries.hasNext())
    {
        Iterator entry=entriesIterator.next();
        Object key=entry.getKey();
        Object value=entry.getValue();
    }
}