Java实现 双链表

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双链表较之单链表多了前趋和后继，但是tail.next都为null

节点类：

public class DNode {
    String name;
    DNode prev;
    DNode next;

    public DNode(String name, DNode prev, DNode next) {
        this.name = name;
        this.prev = prev;
        this.next = next;
    }

    public DNode(String name) {
        this.name = name;
        this.prev = null;
        this.next = null;
    }
    public DNode() {
        this.prev = null;
        this.next = null;
    }
}

链表类：

public class DLink {
    public DNode head;

    public DLink() {
        this.head = new DNode();
    }

    public void addNode(String name) {
        DNode d = head;
        while (d.next != null) {
            d = d.next;
        }
        d.next = new DNode(name, d, null);
    }

    /**
     * 删除某节点
     * @param name
     */
    public void delNode(String name) {
        DNode d = head;
        //遍历
        while (d.next != null) {
            if(d.next.name.equals(name)) {
                //更改将要删除节点后一节点的前趋为current
                d.next.next.prev = d.next.prev;
                d.next = d.next.next;
                break;
            }else {
                d = d.next;
            }
        }

    }

    /**
     * data 前插入节点
     * @param data
     * @param name
     * @return
     */
    public boolean insertNode(String data,String name) {
        DNode d = head;
        DNode insertNode = new DNode(name, null, null);
        while (d.next != null) {
            if(d.next.name.equals(data)) {
                /**
                 * 设置插入节点的前趋和后继（d.next 为当前节点data）
                 */
                insertNode.next = d.next;
                insertNode.prev = d.next.prev;
                /**
                 * 设置当前节点的前趋
                 */
                d.next.prev = insertNode;
                /**
                 * 设置当前节点
                 */
                d.next = insertNode;
                return true;
            }else {
                d = d.next;
            }
        }
        return false;
    }

    /**
     * 替换某节点的值
     * @param data
     * @param name
     * @return
     */
    public boolean setValue(String data,String name) {
        DNode d = head;
        while (d.next != null) {
            d = d.next;
            if(d.name.equals(data)) {
                d.name = name;
                return true;
            }
        }
        return false;
    }

    /**
     * 遍历
     */
    public void display() {
        DNode d = head;
        while (d.next != null) {
            d = d.next;
            System.out.println(d.name);
        }
    }

}

测试代码：

        DLink dLink = new DLink();
        dLink.addNode("1");
        dLink.addNode("2");
        dLink.addNode("3");
        dLink.addNode("4");
        dLink.display();
        System.out.println("-------------------------");
        dLink.setValue("3","5");
        dLink.display();