笔记篇-Google Guava快速入门

简介

Guava是一种基于开源的Java库，其中包含谷歌正在由他们很多项目使用的很多核心库。这个库是为了方便编码，并减少编码错误。这个库提供用于集合，缓存，支持原语，并发性，常见注解，字符串处理，I/O和验证的实用方法。

特点

• 标准化 - Guava库是由谷歌托管。
• 高效 - 可靠，快速和有效的扩展JAVA标准库
• 优化 -Guava库经过高度的优化。

入门

<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>30.1.1-jre</version>
  <!-- or, for Android: -->
  <version>30.1.1-android</version>
</dependency>

教程

Guava 的 Java 反射机制工具类

基本工具

Make using the Java language more pleasant.

• Using and avoiding null: null can be ambiguous, can cause confusing errors, and is sometimes just plain unpleasant. Many Guava utilities reject and fail fast on nulls, rather than accepting them blindly.
• Preconditions: Test preconditions for your methods more easily.
• Common object methods: Simplify implementing Object methods, like hashCode() and toString().
• Ordering: Guava’s powerful “fluent Comparator“ class.
• Throwables: Simplify propagating and examining exceptions and errors.

集合

Guava’s extensions to the JDK collections ecosystem. These are some of the most mature and popular parts of Guava.

• Immutable collections, for defensive programming, constant collections, and improved efficiency.
• New collection types, for use cases that the JDK collections don’t address as well as they could: multisets, multimaps, tables, bidirectional maps, and more.
• Powerful collection utilities, for common operations not provided in java.util.Collections.
• Extension utilities: writing a Collection decorator? Implementing Iterator? We can make that easier.

图表

a library for modeling graph

• structured data, that is, entities and the relationships between them. Key features include:
• Graph: a graph whose edges are anonymous entities with no identity or information of their own.
• ValueGraph: a graph whose edges have associated non-unique values.
• Network: a graph whose edges are unique objects.
• Support for graphs that are mutable and immutable, directed and undirected, and several other properties.

缓存

缓存: Local caching, done right, and supporting a wide variety of expiration behaviors.

函数式编程

• 函数式编程: Used sparingly, Guava’s functional idioms can significantly simplify code.

并发

• 并发: Powerful, simple abstractions to make it easier to write correct concurrent code.
  • ListenableFuture: Futures, with callbacks when they are finished.
  • Service: Things that start up and shut down, taking care of the difficult state logic for you.

字符操作

• 字符操作: A few extremely useful string utilities: splitting, joining, padding, and more.

原生类型

• 原生类型: operations on primitive types, like int and char, not provided by the JDK, including unsigned variants for some types.

区间

• 区间: Guava’s powerful API for dealing with ranges on Comparable types, both continuous and discrete.

I/O

• I/O: Simplified I/O operations, especially on whole I/O streams and files, for Java 5 and 6.

哈希

• 哈希: Tools for more sophisticated hashes than what’s provided by Object.hashCode(), including Bloom filters.

事件总线

• 事件总线: Publish-subscribe-style communication between components without requiring the components to explicitly register with one another.

数学运算

• 数学运算: Optimized, thoroughly tested math utilities not provided by the JDK.

反射

• 反射: Guava utilities for Java’s reflective capabilities.

参考

官方文档

github guava 地址

https://www.baeldung.com/guava-guide