ArrayList与LinkedList的性能对比

ArrayList与LinkedList都是继承至Collection对象,内部实现导致性能方面存在一定的区别

1. 插入性能对比

   private final static int COUNT = 10000000;
   
   private static long insertObject(List<Object> list) {
       Object obj = new Object();
       long startTime = System.currentTimeMillis();
       for (int i = 0; i < COUNT; i++) {
           list.add(obj);
       }
       long endTime = System.currentTimeMillis();
       return endTime - startTime;
   }
   
   public static void main(String[] args) {
       int initCount = (int) (COUNT * 1.5);
       System.out.println("ArrayList 增加" + COUNT + "条数据,耗时:" + insertObject(new ArrayList<Object>(initCount)));
       System.out.println("LinkedList 增加" + COUNT + "条数据,耗时:" + insertObject(new LinkedList<Object>()));
   }

   上述代码得出下列结果:
   

2. 查询性能对比

    private final static int COUNT = 1000000;

    private static Map<String, Object> insertObject(List<Object> list) {
        User user = new User();
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < COUNT; i++) {
            user.setId(i);
            user.setName("i:" + i);
            user.setAge(i);
            list.add(user);
        }
        long endTime = System.currentTimeMillis();
        Map result = new HashMap<String, Object>();
        result.put("time", endTime - startTime);
        result.put("list", list);
        return result;
    }

    private static long readObject(List<User> list) {
        long startTime = System.currentTimeMillis();
        for (User user : list) {

        }
        long endTime = System.currentTimeMillis();
        return endTime - startTime;
    }

    public static void main(String[] args) {
        // 插入
        int initCount = (int) (COUNT * 1.5);
        Map<String, Object> arrayListResult = insertObject(new ArrayList<Object>());
        Map<String, Object> linkedListResult = insertObject(new LinkedList<Object>());
        System.out.println("ArrayList 增加" + COUNT + "条数据,耗时:" + arrayListResult.get("time"));
        System.out.println("LinkedList 增加" + COUNT + "条数据,耗时:" + linkedListResult.get("time"));

        // 读取
        System.out.println("ArrayList 查询" + COUNT + "条数据,耗时:" + readObject((List<User>) arrayListResult.get("list")));
        System.out.println("LinkedList 查询" + COUNT + "条数据,耗时:" + readObject((List<User>) linkedListResult.get("list")));
    }

1. 修改性能对比
2. 移除性能对比

原文地址：https://blog.51cto.com/11219183/2401485