check here. tip: 当使用remove方法时,index后边的元素要自动前移.Nothing special.…

http://www.onjava.com/pub/a/onjava/2001/05/30/optimization.htmlComparing the performance of LinkedLists and ArrayLists (and Vectors) (Page last updated May 2001, Added 2001-06-18, Author Jack Shirazi, Publisher OnJava). Tips: ArrayList is faster than…

第1部分 ArrayList介绍ArrayList底层采用数组实现,它的容量能动态增长.它继承于AbstractList,实现了List, RandomAccess, Cloneable, java.io.Serializable这些接口. public class ArrayList<E> extends AbstractList<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable…

一.遍历方式 ArrayList支持三种遍历方式. 1.第一种,随机访问,它是通过索引值去遍历 由于ArrayList实现了RandomAccess接口,它支持通过索引值去随机访问元素. 代码如下: // 基本的forfor (int i = 0; i < size; i++){    value = list.get(i);} 2.第二种,foreach语句 foreach语句是java5的新特征之一,在遍历数组.集合方面,foreach为开发人员提供了极大的方便. 代码如下: for (In…

/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * * * * * * * * * * * * * * * * * * * * */ package java.util; import java.util.function.Consumer; im…

The size, isEmpty, get, set, iterator, and listIterator operations run in constant time. The add operation runs in amortized constant time, that is, adding n elements requires O(n) time. All of the other operations run in linear time (roughly speakin…

1. 数据结构之List (java:接口)[由于是分析原理,这里多用截图说明] List是集合类中的容器之一,其定义如下:(无序可重复) An ordered collection (also known as a sequence). The user of this interface has precise control over where in the list each element iinserted. The user can access elements by thei…

在看ArrayList源码时,看到了一个字段modCount.在add.remove.clear等方法中都有modCount++的操作.不明白什么意思.点进去看了看该字段的解释,总算明白了.modCount是在AbstractList抽象类中定义的.该字段的解释如下所示. /** * The number of times this list has been <i>structurally modified</i>. * Structural modifications are…

Preface Validating data is a common task that occurs throughout all application layers, from the presentation to the persistence layer. Often the same validation logic is implemented in each layer which is time consuming and error-prone. To avoid dup…

ArrayList.LinkedList.HashMap是Java开发中非常常见的数据类型.它们的区别也非常明显的,在Java中也非常具有代表性.在Java中,常见的数据结构是:数组.链表,其他数据结构基本就是这两者的组合. 复习一下数组.链表的特征. 数组:在内存中连续的地址块,查找按照下标来寻址,查找快速.但是插入元素和删除元素慢,需要移动元素. 链表:内存中逻辑上可以连接到一起的一组节点.每个节点除了存储本身,还存储了下一个元素的地址.查找元素需要依次找找各个元素,查找慢,插入和删除元素只…