LinkList 与ArrayList的不同

LinkList 是基于链表的，
ArrayList 是基于数据的，
本人自己测试的结果是ArrayList的增删盖查的速度均好于LinkList。
以下是测试的代码：

package main;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.RandomAccess;

/**
 * 测试Random Access List(随机访问列表)如 ArrayList 和 Sequence Access List(顺序访问列表)如 LinkedList </br>
 * 不同遍历算法的效率</br>
 * 结论：前者用循环，后者用迭代器
 */
@SuppressWarnings({"rawtypes", "unchecked"})
public class ListTest {

    public static void printlnListRandomAccess(List list) {
        if (list instanceof RandomAccess) {
            System.out.println("实现了 RandomAccess 接口...");
        } else {
            System.out.println("没实现 RandomAccess 接口...");
        }
    }
    /**
     * 查询指定位置的数
     * @param list
     * @param position
     * @param <T>
     * @return
     */
    public static <T> List getList(List list, int position) {
        printlnListRandomAccess(list);
        long startTime = System.currentTimeMillis();
        list.get(position);
        long endTime = System.currentTimeMillis();
        System.out.println("remove时间：" + (endTime - startTime));
        return list;
    }
    /**
     * remove指定位置的数
     * @param list
     * @param position
     * @param <T>
     * @return
     */
    public static <T> List removeList(List list, int position) {
        printlnListRandomAccess(list);
        long startTime = System.currentTimeMillis();
        list.remove(position);
        long endTime = System.currentTimeMillis();
        System.out.println("remove时间：" + (endTime - startTime));
        return list;
    }
    /**
     * 在指定位置添加数
     * @param list
     * @param n
     * @param position
     * @param <T>
     * @return
     */
    public static <T> List addList(List list, int n,int position) {
        printlnListRandomAccess(list);
        long startTime = System.currentTimeMillis();
        list.add(position,n);
        long endTime = System.currentTimeMillis();
        System.out.println("add时间：" + (endTime - startTime));
        return list;
    }
    /**
     * 更新指定位置的数
     * @param list
     * @param n
     * @param position
     * @param <T>
     * @return
     */
    public static <T> List setList(List list, int n,int position) {
        printlnListRandomAccess(list);
        long startTime = System.currentTimeMillis();
        list.set(position,n);
        long endTime = System.currentTimeMillis();
        System.out.println("set时间：" + (endTime - startTime));
        return list;
    }
    /**
     * 初始化 list，添加n个元素
     * @param list
     * @return
     */
    public static <T> List initList(List list, int n) {
        if (list instanceof RandomAccess) {
            System.out.println("实现了 RandomAccess 接口...");
        } else {
            System.out.println("没实现 RandomAccess 接口...");
        }
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < n; i++)
            list.add(i);
        long endTime = System.currentTimeMillis();
        System.out.println("遍历时间：" + (endTime - startTime));
        return list;
    }

    /**
     * 遍历 list，判断是否实现 RandomAccess 接口来使用不同的遍历方法
     * @param list
     */
    public static void accessList(List list) {
        long startTime = System.currentTimeMillis();
        if (list instanceof RandomAccess) {
            System.out.println("实现了 RandomAccess 接口...");
            for (int i = 0; i < list.size(); i++) {
                list.get(i);
            }
        } else {
            System.out.println("没实现 RandomAccess 接口...");
            for (Iterator iterator = list.iterator(); iterator.hasNext(); ) {
                iterator.next();
            }
        }
        long endTime = System.currentTimeMillis();
        System.out.println("遍历时间：" + (endTime - startTime));
    }

    /**
     * loop 遍历 list
     */
    public static void accessListByLoop(List list) {
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < list.size(); i++) {
            list.get(i);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("loop遍历时间：" + (endTime - startTime));
    }

    /**
     * 迭代器遍历
     */
    public static void accessListByIterator(List list) {
        long startTime = System.currentTimeMillis();
        for (Iterator iterator = list.iterator(); iterator.hasNext(); ) {
            iterator.next();
        }
        long endTime = System.currentTimeMillis();
        System.out.println("Iterator遍历时间：" + (endTime - startTime));
    }

    public static void main(String[] args) {
        ArrayList<Integer> aList = (ArrayList<Integer>) initList(new ArrayList<>(), 10000000);
        LinkedList<Integer> lList = (LinkedList<Integer>) initList(new LinkedList<>(), 10000000);
//        accessList(aList);
//        accessList(lList);
//        System.out.println("ArrayList");
//        accessListByLoop(aList);
//        accessListByIterator(aList);
//        System.out.println("LinkedList");
//        accessListByLoop(lList);
//        accessListByIterator(lList);
        addList(aList,987654321,8000000);
        addList(lList,987654321,8000000);
        removeList(aList,8000000);
        removeList(lList,8000000);
        setList(aList,987654321,8000000);
        setList(lList,987654321,8000000);
        getList(aList,8000000);
        getList(lList,8000000);
    }

}

测试结果：

1583227064(1).jpg