前言

• HashMap 在 Java 和 Android 开发中非常常见
• 而HashMap 1.8 相对于 HashMap 1.7 更新多
• 今天，我将通过源码分析HashMap 1.8 ，从而讲解HashMap 1.8 相对于 HashMap 1.7 的更新内容，希望你们会喜欢。

本文基于版本 JDK 1.8，即 Java 8关于版本 JDK 1.7，即 Java 7，具体请看文章Java：手把手带你源码分析 HashMap 1.7

目录

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/8c1edf35-14c8-4d5b-a8e4-09c55ab5e83d/aHR0cHM6Ly9pbWdjb252ZXJ0LmNzZG5pbWcuY24vYUhSMGNITTZMeTlwYldkamIyNTJaWEowTG1OelpHNXBiV2N1WTI0dllVaFNNR05FYjNaTU0xWjNZa2M1YUZwRE1YQmlWMFp1V2xoTmRXRnRiR2hpYms1dlpGTTFjR0o1T1RGalIzaDJXVmRTWm1GWE1XaGFNbFo2VEhwck1FNUVUVEpPVXpBeFRYcGpkMDFFV21oYWFsa3pXVlJaZVU1NlZUVk1ia0oxV25vNWNHSlhSbTVhVlRGMldqTkplVXd5UmpGa1J6aDBZak5LY0ZwWE5UQk1NMDR3WTIxc2QwcFVaRVJoVnpGb1dqSldWMkZYVmpOTmFUaDVURE5qZGsxVVNUQk5RUQ

1. 简介

• 类定义

public class HashMap<K,V>
         extends AbstractMap<K,V>
         implements Map<K,V>, Cloneable, Serializable

• 主要简介

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/da2d1a22-096a-42d9-b79b-b1e006c7d292/aHR0cHM6Ly9pbWdjb252ZXJ0LmNzZG5pbWcuY24vYUhSMGNITTZMeTlwYldkamIyNTJaWEowTG1OelpHNXBiV2N1WTI0dllVaFNNR05FYjNaTU0xWjNZa2M1YUZwRE1YQmlWMFp1V2xoTmRXRnRiR2hpYms1dlpGTTFjR0o1T1RGalIzaDJXVmRTWm1GWE1XaGFNbFo2VEhwck1FNUVUVEpPVXpCM1QwUmFhVTVVYUdoYVYxWnNUVzFSZDAxSFRtbE1ia0oxV25vNWNHSlhSbTVhVlRGMldqTkplVXd5UmpGa1J6aDBZak5LY0ZwWE5UQk1NMDR3WTIxc2QwcFVaRVJoVnpGb1dqSldWMkZYVmpOTmFUaDVURE5qZGsxVVNUQk5RUQ

• HashMap 的实现在 JDK 1.7 和 JDK 1.8 差别较大
• 今天，我将对照 JDK 1.7的源码，在此基础上讲解 JDK 1.8 中 HashMap 的源码解析

请务必打开JDK 1.7对照看：Java：手把手带你源码分析 HashMap 1.7

2. 数据结构：引入了 红黑树

2.1 主要介绍

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/6d0b4c09-501f-4021-b9f4-46fb7c390d2b/aHR0cHM6Ly9pbWdjb252ZXJ0LmNzZG5pbWcuY24vYUhSMGNITTZMeTlwYldkamIyNTJaWEowTG1OelpHNXBiV2N1WTI0dllVaFNNR05FYjNaTU0xWjNZa2M1YUZwRE1YQmlWMFp1V2xoTmRXRnRiR2hpYms1dlpGTTFjR0o1T1RGalIzaDJXVmRTWm1GWE1XaGFNbFo2VEhwck1FNUVUVEpPVXpBMVQwUkZNMDlFWTNkT2VtY3hUbFJaTTA0eVNtcE1iWEIzV25vNWNHSlhSbTVhVlRGMldqTkplVXd5UmpGa1J6aDBZak5LY0ZwWE5UQk1NMDR3WTIxc2QwcFVaRVJoVnpGb1dqSldWMkZYVmpOTmFUaDVURE5qZGsxVVNUQk5RUQ

关于 红黑树 了解：http://blog.csdn.net/v_july_v/article/details/6105630

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/81746bd0-883f-4f5a-97a3-9221355ab6ec/aHR0cHM6Ly9pbWdjb252ZXJ0LmNzZG5pbWcuY24vYUhSMGNITTZMeTlwYldkamIyNTJaWEowTG1OelpHNXBiV2N1WTI0dllVaFNNR05FYjNaTU0xWjNZa2M1YUZwRE1YQmlWMFp1V2xoTmRXRnRiR2hpYms1dlpGTTFjR0o1T1RGalIzaDJXVmRTWm1GWE1XaGFNbFo2VEhwck1FNUVUVEpPVXpGcldYcG9hVTF0U1RKWlYxVjVUbXBzYlZwdFZteE1ia0oxV25vNWNHSlhSbTVhVlRGMldqTkplVXd5UmpGa1J6aDBZak5LY0ZwWE5UQk1NMDR3WTIxc2QwcFVaRVJoVnpGb1dqSldWMkZYVmpOTmFUaDVURE5qZGsxVVNUQk5RUQ