去重错误

/**
   public void deleteDuplecate() {
    Hashtable<Integer, Integer> table = new Hashtable<>();
    Node temp = head;
    Node tempnext = head.next;
    while (tempnext != null){
        if(table.containsKey(temp.date)){
            temp = tempnext;
        }
        else {
            table.put(temp.date,temp.date);
        }
        temp = tempnext;
        tempnext = tempnext.next;

    }
    temp = head;
    while (temp != null){
        System.out.println(temp.date);
        temp = temp.next;
    }
}
*/