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java集合之HashMap

前言：HashMap作为面试必备题目，是需要每个java程序员都得研究的，这里总结下JDK8之后HashMap的实现。一.HashMap的特点？HashMap是Map的实现类之一，HashMap的底层是hash表，hash表是用来控制键值对中的键的，并且HashMap的键是可以为null的ÿ...

Java集合 - HashMap

介绍 HashMapMap 是一种存储键值对的集合。Map 集合可以根据 key 快速查找对应的 value 值。HashMap 是 Map 类型的一中。HashMap 的底层存储结构是：数组 + 链表 + 红黑树。下面我们通过 HashMap 的新增操作、查找操作来看 HashMap 的底层存储结...

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Java 集合之一 —HashMap（二）

三、为何 HashMap 的数组长度一定是 2 的次幂？我们来继续看上面提到的 resize 方法void resize(int newCapacity) { Entry[] oldTable = table; int oldCapacity = oldTable.length; if (oldCa...

Java 集合之一 —HashMap（一）

深入浅出学 Java——HashMap哈希表（hash table）也叫散列表，是一种非常重要的数据结构，应用场景及其丰富，许多缓存技术（比如 memcached）的核心其实就是在内存中维护一张大的哈希表，本文会对 java 集合框架中 HashMap 的实现原理进行讲解，...

Java性能调优，如何将java HashSet集合对象转换为HashMap，有没有性能更快的做法？

Java集合---HashMap源码剖析

Java集合---HashMap源码剖析一、HashMap概述二、HashMap的数据结构三、HashMap源码分析 1、关键属性 2、构造方法 3、存储数据 ...

java 集合问题。 HashMap的问题

HashMap map=new HashMap(); map.pub(1,12); map.pub(2,23); Set set1=map.keySet(); System.out.println(set1.toString()); while(Object key2:set1){ //Object...

深入Java集合系列之三：HashMap

前言无意中发现有很多对Map尤其是HashMap的线程安全性的话题讨论，在我的理解中，对HashMap的理解中也就知道它是线程不安全的，以及HashMap的底层算法采用了链地址法来解决哈希冲突的知识，但是对其线程安全性的认知有限，故写这篇博客的目的就是让和我对这块内容不熟悉的小伙伴有一个对Hash...

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