java - 从 LinkedList 中删除特定元素....？

Question

我试图从链表中删除一个特定的元素，但是我得到空指针异常。任何人都可以修复我下面提到的代码......

public void deleteElement(T num)
    {
        Node<T> ele = new Node<T>(num);
        if(head == null){
            System.out.println("Underflow");
            return;
        }
        Node<T> temp = head;
        while(temp != null)
        {
            if(temp.data == num){
                temp.previous.next = temp.next;
                return;
            }
            else
                temp = temp.next;
        }
        size--;
    }

Answer 1

你应该像这样在你的 while 循环中修改:

while(temp != null)
{
    if(temp.data == num) {
        if(temp.previous != null) {
            temp.previous.next = temp.next;
        }
        // you have to link-up the next's previous with temp's previous too 
        if(temp.next != null) {
            temp.next.previous = temp.previous;
        }
        temp = null; // to deference the node and let garbage collector to delete/clear this node
        break; // don't return here otherwise size-- won't execute
    }
    temp = temp.next;
}

在将 temp.next 和 temp.previous 引用为左值之前，您应该检查它们是否为 null 否则将抛出 NullPointerException 。

希望对您有所帮助!