不明白???

05-05-10 wwx
我是学JAVA的新手,看到一个网页不太明白,请高手指教12:

(1)public Iterator getUsers() {

final ResultSet rs = userDbQuery();

return new Iterator() {

private Object next;

public void hasNext() {

if (next == null) {

if (! rs.next()) {

return false;

}

next = rs.getString(1);

}

return true;

}

public Object next() {

if (! hasNext()) {

throw new NoSuchElementException();

}

String retval = next;

next = null;

return retval;

}

public void remove() {

throw new UnsupportedOperationException("no remove allowed");

}

}

}

(2)public Iterator getUsers() {

ResultSet rs = userDbQuery();

List list = new ArrayList()

while (rs.next()) {

list.add(rs.getString(1));

}

return list.iterator();

}

(3)为何1返回的是指针而2不是

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