Java实现 双链表互换任意两个节点

1、确定两个节点的先后顺序
2、next、prev互相交换顺序以及将换向前方的节点与之前的节点对接。（1.prev.next = 2）
3、判断是否相邻

链表类：

public class SLink {
    public SNode head;

    public SLink() {
        this.head = new SNode();
    }
    public boolean interChangeById(int id1,int id2) {
        SNode s = head;
        SNode node1 = null,node2 = null;
        int node1Count,node2Count;
        node1Count = node2Count = 0;

        if(id1 == id2) {
            return true;
        }

        /**
         * 向下遍历
         */
        while (s.next != null) {
            s = s.next;
            node1Count ++ ;
            if(s.student.stuId == id1) {
                /**
                 * 记录节点1
                 */
                node1 = s;
                break;
            }

        }

        s = head;
        while (s.next != null) {
            s = s.next;
            node2Count ++ ;
            if(s.student.stuId == id2) {
                /**
                 * 记录节点2
                 */
                node2 = s;
                break;
            }
        }


        if(node1 != null && node2 != null) {
            SNode temp = new SNode();
            /**
             * node1在后
             */
            if(node1Count > node2Count) {
                temp.next = node1.next;
                temp.prev = node1.prev;
                /**
                 * 记录那个节点就先处理那个节点
                 * 1、交换next
                 * 2、交换prev
                 * 3、设置之前节点的next（对接）
                 */
                node1.next = node2.next;
                node1.prev = node2.prev;
                node2.prev.next = node1;

                if(node1.next.equals(node1)) {
                    /**
                     * 说明两个节点相邻
                     */
                    node1.next = node2;

                    node2.next = temp.next;
                    node2.prev = node1;
                }else {
                    /**
                     * 说明节点不相邻
                     */
                    node2.next = temp.next;
                    node2.prev = temp.prev;
                    temp.prev.next = node2;
                }
            }else {
                /**
                 * node1在前
                 */
                temp.next = node2.next;
                temp.prev = node2.prev;

                node2.next = node1.next;
                node2.prev = node1.prev;
                node1.prev.next = node2;
                if(node2.next.equals(node2)) {
                    node2.next = node1;

                    node1.next = temp.next;
                    node1.prev = node2;
                }else {
                    node1.next = temp.next;
                    node1.prev = temp.prev;
                    temp.prev.next = node1;
                }
            }
            return true;
        }
        return false;
    }
    public void displayStudent() {
        SNode s = head;
        while (s.next != null) {
            s = s.next;
            System.out.println(s.student);
        }
    }
}

节点类：

public class SNode {
    public Student student;
    public SNode next;
    public SNode prev;

    public SNode(Student student, SNode prev,SNode next) {
        this.student = student;
        this.next = next;
        this.prev = prev;
    }
    public SNode() {
        this.student = null;
        this.next = null;
        this.prev = null;
    }
}

Student类：

public class Student {
    public int stuId;
    public String name;
    public int age;
    public String className;

    public Student(int stuId, String name, int age, String className) {
        this.stuId = stuId;
        this.name = name;
        this.age = age;
        this.className = className;
    }

    public int getStuId() {
        return stuId;
    }

    public void setStuId(int stuId) {
        this.stuId = stuId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    @Override
    public String toString() {
        return "Student{" +
                "stuId=" + stuId +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", className='" + className + '\'' +
                '}';
    }
}