talk is cheap，show you zhe code；

/*
 * 單鏈表的遍歷是從第0個節點開始  沿著next鏈，一次訪問每個節點並且每個節點只能訪問一次
 * 當頭結點head為空時  此連結串列為空連結串列
 * 
 * 插入操作
 * 1空表插入  判斷是否為空  插入的節點為該鏈的頭結點
 * 2頭插入
 *  Node<T> p = new Node<x,null>;//建立值為x的p結點
 *  p.next= head;                //p.next指向頭結點
 *  head=p;
 *  
 * 3
 */
public class
 
 Node<T> {
    public T data;
    public Node<T> next;

    public Node (T data,Node<T> next){
        this.data=data;
        this.next=next;
    }
    public Node(){
        this(null,null);
    }
    public String toString(){
        if(data==null)
            return null;
        return
 
 data.toString();
    }
}

package dataStructure.linkList;



/*
 * 頭結點 單鏈表的儲存結構中總是帶著頭結點的，忽略其資料域
 */
public class SingleList<T> {
    public Node<T> head;

    public SingleList() {
        this.head = new Node<T>();                        //呼叫Node的無參構造方法
    }

    public SingleList
 
(T[] values) {
        this();                                           // 建立空單鏈表只有頭結點
        Node<T> rear = this.head;
        for (int i = 0; i < values.length; i++) {
            rear.next = new Node<T>(values[i], null);    //為當前結點的next賦值，並將下一結點指向空      即尾插入
            rear = rear.next;                            // 挪到下一結點
        }
    }

    public boolean isEmpty() {
        // 頭結點 單鏈表的儲存結構中總是帶著頭結點的，忽略其資料域
        // 頭結點為之後為空 則連結串列為空
        return this.head.next == null;
    }

    public T get(int i) {
        Node<T> p = this.head.next;
        for (int j = 0; p != null && j < i; j++) {
            p = p.next; // 獲得後一個結點
        }

        return (i >= 0 && p != null) ? p.data : null;
    }

    public void set(int i) {
    }

    public int size() {
        int size=0;
        Node<T> p = this.head.next;
        if(this.head.next==null){    //判斷第一個結點是否為空
            return 0;
        }
        do{
            p=p.next;
            size++;
        }while(p!=null);
        return size;
    }

    /*
     * @param the loaction of insert
     * 
     * @param value
     * 此處採取了容錯措施  若i<0則插入最前 若i>size則插入在尾部
     */
    public void insert(int i, T x) {
        if (x == null) {
            throw new NullPointerException("x==null");
        }
        Node<T> front = this.head;
        for (int j = 0; front.next != null && j < i; j++) {
            front = front.next; // 遍歷到插入處
        }
        front.next = new Node<>(x, front.next);
    }
    public void insert(T x){
        insert(Integer.MAX_VALUE,x);
    }

    public void remove(int i) {
        Node<T> front = this.head;
        for (int j = 0; front.next != null && j < i; j++) {
            front = front.next; // 遍歷到i-1處
        }
        if (front.next != null && i >= 0) {
            front.next = front.next.next;
        }
    }

    public String toString() {
        String str = this.getClass().getName() + "(";
        for (Node<T> p = this.head.next; p != null; p = p.next) {
            str += p.data.toString();
            if (p.next != null) {
                str += ",";
            }
        }
        str += ")";
        return str;
    }

    public static void main(String[] args) {
        SingleList<String> testhead = new SingleList<String>();
        System.out.println(testhead.head); 
        System.out.println(testhead.head.data);

        Integer[] valuesnumber = { 1, 5, 3, 5, 6, 86, 89, 4, 5, 35, 7 };
        String[] values = { "A", "B", "C", "D" };
        SingleList<String> test = new SingleList<String>(values);


        System.out.println(test.toString()+test.size());
        System.out.println("索引為1 的結點值" + test.get(1).toString());
        test.insert(-1, "insertlocation");
        System.out.println(test.toString());
        test.remove(2);
        test.insert("fd");
        System.out.println(test.toString());

        SingleList<Integer> test2 = new SingleList<Integer>(valuesnumber);
        System.out.println(test2.toString());

    }

}