单链表删除第一次关键字

//删除第一次出现关键字为key的节点
    public void remove(int key){
        ListNode cur = this.head;
        while (cur != null) {
            if(cur.val == key) {
                if(cur == head) {
                    head = head.next;
                    if(head != null) {
                        head.prev = null;
                    }else {
                        last = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if(cur.next != null) {
                        //中间位置
                        cur.next.prev = cur.prev;
                    }else {
                        last = last.prev;
                    }
                }
                return;
            }
            cur = cur.next;
        }
    }