【Java基础】Java开发过程中的常用工具类库

Java开发过程中的常用工具类库

Java开发过程中的常用工具类库

1. Apache Commons类库

Apache Commons是一个非常有用的工具包，为解决各种实际的问题提供了通用现成的代码，不需要我们程序员再重复造轮子。关于这个类库的详细介绍可以访问官网介绍。下面表格列出了部分的工具包。我们平时开发过程中可以根据自己的需要挑选合适的工具包。

Components	Description	Latest Version	Released
BCEL	Byte Code Engineering Library - analyze, create, and manipulate Java class files	6.3.1	2019/3/24
BeanUtils	Easy-to-use wrappers around the Java reflection and introspection APIs.	1.9.3	2016/9/26
BSF	Bean Scripting Framework - interface to scripting languages, including JSR-223	3.1	2010/6/24
Chain	Chain of Responsibility pattern implemention.	1.2	2008/6/2
CLI	Command Line arguments parser.	1.4	2017/3/9
Codec	General encoding/decoding algorithms (for example phonetic, base64, URL).	1.12	2019/2/16
Collections	Extends or augments the Java Collections Framework.	4.3	2019/2/5
Compress	Defines an API for working with tar, zip and bzip2 files.	1.18	2018/8/16
Configuration	Reading of configuration/preferences files in various formats.	2.4	2018/10/29
Crypto	A cryptographic library optimized with AES-NI wrapping Openssl or JCE algorithm implementations.	1.0.0	2016/7/22
CSV	Component for reading and writing comma separated value files.	1.6	2018/9/25
Daemon	Alternative invocation mechanism for unix-daemon-like java code.	1.0.15	2013/4/3
DBCP	Database connection pooling services.	2.6.0	2019/2/19
DbUtils	JDBC helper library.	1.7	2017/7/20
Digester	XML-to-Java-object mapping utility.	3.2	2011/12/13
Email	Library for sending e-mail from Java.	1.5	2017/8/1
Exec	API for dealing with external process execution and environment management in Java.	1.3	2014/11/6
FileUpload	File upload capability for your servlets and web applications.	1.4	2019/1/16
Functor	A functor is a function that can be manipulated as an object, or an object representing a single, generic function.	1	2011-??-??
Geometry	Space and coordinates.	1	2018-??-??
Imaging (previously called Sanselan)	A pure-Java image library.	0.97-incubator	2009/2/20
IO	Collection of I/O utilities.	2.6	2017/10/15
JCI	Java Compiler Interface	1.1	2013/10/14
JCS	Java Caching System	2.2,1	2018/8/23
Jelly	XML based scripting and processing engine.	1.0.1	2017/9/27
Jexl	Expression language which extends the Expression Language of the JSTL.	3.1	2017/4/14
JXPath	Utilities for manipulating Java Beans using the XPath syntax.	1.3	2008/8/14
Lang	Provides extra functionality for classes in java.lang.	3.9	2019/4/15
Logging	Wrapper around a variety of logging API implementations.	1.2	2014/7/11
Math	Lightweight, self-contained mathematics and statistics components.	3.5	2015/4/17
Net	Collection of network utilities and protocol implementations.	3.6	2017/2/15
Numbers	Number types (complex, quaternion, fraction) and utilities (arrays, combinatorics).	1	2017-??-??
OGNL	An Object-Graph Navigation Language	4	2013-??-??
Pool	Generic object pooling component.	2.6.2	2019/4/11
Proxy	Library for creating dynamic proxies.	1	2008/2/28
RDF	Common implementation of RDF 1.1 that could be implemented by systems on the JVM.	0.3.0-incubating	2016/11/15
RNG	Implementations of random numbers generators.	1.2	2018/12/12
SCXML	An implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.It is capable of executing a state machine defined using a SCXML document, and abstracts out the environment interfaces.	0.9	2008/12/1
Statistics	Statistics.	0.1	????-??-??
Text	Apache Commons Text is a library focused on algorithms working on strings.	1.6	2018/10/16
Validator	Framework to define validators and validation rules in an xml file.	1.6	2017/2/21
VFS	Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.	2.3	2019/2/4
Weaver	Provides an easy way to enhance (weave) compiled bytecode.	2	2018/9/7

除了上面表格中的工具包，Apache Common项目还包括以下几个工具包，其中的http-client是我们平时非常常用的。

Cactus: Cactus is a simple test framework for unit testing server-side java code (Servlets, EJBs, Tag Libs, Filters, ...). The intent of Cactus is to lower the cost of writing tests for server-side code.
HiveMind: HiveMind is a services and configuration microkernel. HiveMind allows you to create your application using a service oriented architecture.
HttpClient 3.x: Framework for working with the client-side of the HTTP protocol.
Naming: The Naming subproject will contain common JNDI code along with various JNDI providers.

2. Guava类库

Guava工程包含了若干被Google的 Java项目广泛依赖的核心库，例如：集合 [collections] 、缓存 [caching] 、原生类型支持 [primitives support] 、并发库 [concurrency libraries] 、通用注解 [common annotations] 、字符串处理 [string processing] 、I/O 等等。下面列出Guava工具包中的常用功能点，以便需要的时候查阅使用。

2.1 基本工具 [Basic utilities]

使用和避免null：null是模棱两可的，会引起令人困惑的错误，有些时候它让人很不舒服。很多Guava工具类用快速失败拒绝null值，而不是盲目地接受。
前置条件: 让方法中的条件检查更简单。
常见Object方法: 简化Object方法实现，如hashCode()和toString()。
排序: Guava强大的”流畅风格比较器”
Throwables：简化了异常和错误的传播与检查。

2.2 集合[Collections]

Guava对JDK集合的扩展，这是Guava最成熟和为人所知的部分

不可变集合: 用不变的集合进行防御性编程和性能提升。
新集合类型: multisets, multimaps, tables, bidirectional maps等。
强大的集合工具类: 提供java.util.Collections中没有的集合工具。
扩展工具类：让实现和扩展集合类变得更容易，比如创建Collection的装饰器，或实现迭代器。

2.3 缓存[Caches]

Guava Cache：本地缓存实现，支持多种缓存过期策略。

2.4 函数式风格[Functional idioms]

Guava的函数式支持可以显著简化代码，但请谨慎使用它。

2.5 并发[Concurrency]

强大而简单的抽象，让编写正确的并发代码更简单

ListenableFuture：完成后触发回调的Future
Service框架：抽象可开启和关闭的服务，帮助你维护服务的状态逻辑

2.6 字符串处理[Strings]

非常有用的字符串工具，包括分割、连接、填充等操作

2.7 原生类型[Primitives]

扩展 JDK 未提供的原生类型（如int、char）操作，包括某些类型的无符号形式

2.8 区间[Ranges]

可比较类型的区间API，包括连续和离散类型

2.9 I/O

简化I/O尤其是I/O流和文件的操作，针对Java5和6版本

2.10 散列[Hash]

提供比Object.hashCode()更复杂的散列实现，并提供布鲁姆过滤器的实现

2.11 事件总线[EventBus]

发布-订阅模式的组件通信，但组件不需要显式地注册到其他组件中

2.12 数学运算[Math]

优化的、充分测试的数学工具类

2.13 反射[Reflection]

Guava 的 Java 反射机制工具类

3. Spring中的常用工具类

FileCopyUtils；
WebUtil；

参考下面博客：
https://www.cnblogs.com/davidwang456/p/4106519.html
https://www.jb51.net/article/125424.htm

4. 其他工具

后续逐渐添加～

参考

并发编程网Guava教程
Apache Common官网