排名Top 16的Java实用类库

在Java中，有很多比较实用的类库，他们通常都定义了一系列具有常见功能的方法。本文总结了最常用的Java中的实用类以及他们的最常用的方法。无论是类和类中方法都是按照流行程度来排序的。

本文中列出来的类及方法都是经过大量实践的常用类库及方法，我们可以直接拿过来用。当然，这些方法实现的功能我们自己都能实现，但是既然已经有很成熟的方法可以供我们使用了，那么就无需自己定义了。很多类和方法通过他们的名字其实可以理解出具体是做什么的。每个方法都有一个链接，可以查看他们在开源代码中具体是如何使用的。

以下列表是通过分析50K的开源项目得出来的。

1. org.apache.commons.io.IOUtils

closeQuietly ( )

toString ( )

copy ( )

toByteArray ( )

write ( )

toInputStream ( )

readLines ( )

copyLarge ( )

lineIterator ( )

readFully ( )

2. org.apache.commons.io.FileUtils

deleteDirectory ( )

readFileToString ( )

deleteQuietly ( )

copyFile ( )

writeStringToFile ( )

forceMkdir ( )

write ( )

listFiles ( )

copyDirectory ( )

forceDelete ( )

3. org.apache.commons.lang.StringUtils

isBlank ( )

isNotBlank ( )

isEmpty ( )

isNotEmpty ( )

equals ( )

join ( )

split ( )

EMPTY

trimToNull ( )

replace ( )

4. org.apache.http.util.EntityUtils

toString ( )

consume ( )

toByteArray ( )

consumeQuietly ( )

getContentCharSet ( )

5. org.apache.commons.lang3.StringUtils

isBlank ( )

isNotBlank ( )

isEmpty ( )

isNotEmpty ( )

join ( )

equals ( )

split ( )

EMPTY

replace ( )

capitalize ( )

6. org.apache.commons.io.FilenameUtils

getExtension ( )

getBaseName ( )

getName ( )

concat ( )

removeExtension ( )

normalize ( )

wildcardMatch ( )

separatorsToUnix ( )

getFullPath ( )

isExtension ( )

7. org.springframework.util.StringUtils

hasText ( )

hasLength ( )

isEmpty ( )

commaDelimitedListToStringArray ( )

collectionToDelimitedString ( )

replace ( )

delimitedListToStringArray ( )

uncapitalize ( )

collectionToCommaDelimitedString ( )

tokenizeToStringArray ( )

8. org.apache.commons.lang.ArrayUtils

contains ( )

addAll ( )

clone ( )

isEmpty ( )

add ( )

EMPTY_BYTE_ARRAY

subarray ( )

indexOf ( )

isEquals ( )

toObject ( )

9. org.apache.commons.lang.StringEscapeUtils

escapeHtml ( )

unescapeHtml ( )

escapeXml ( )

escapeSql ( )

unescapeJava ( )

escapeJava ( )

escapeJavaScript ( )

unescapeXml ( )

unescapeJavaScript ( )

10. org.apache.http.client.utils.URLEncodedUtils

format ( )

parse ( )

11. org.apache.commons.codec.digest.DigestUtils

md5Hex ( )

shaHex ( )

sha256Hex ( )

sha1Hex ( )

sha ( )

md5 ( )

sha512Hex ( )

sha1 ( )

12. org.apache.commons.collections.CollectionUtils

isEmpty ( )

isNotEmpty ( )

select ( )

transform ( )

filter ( )

find ( )

collect ( )

forAllDo ( )

addAll ( )

isEqualCollection ( )

13. org.apache.commons.lang3.ArrayUtils

contains ( )

isEmpty ( )

isNotEmpty ( )

add ( )

clone ( )

addAll ( )

subarray ( )

indexOf ( )

EMPTY_OBJECT_ARRAY

EMPTY_STRING_ARRAY

14. org.apache.commons.beanutils.PropertyUtils

getProperty ( )

setProperty ( )

getPropertyDescriptors ( )

isReadable ( )

copyProperties ( )

getPropertyDescriptor ( )

getSimpleProperty ( )

isWriteable ( )

setSimpleProperty ( )

getPropertyType ( )

15. org.apache.commons.lang3.StringEscapeUtils

unescapeHtml4 ( )

escapeHtml4 ( )

escapeXml ( )

unescapeXml ( )

escapeJava ( )

escapeEcmaScript ( )

unescapeJava ( )

escapeJson ( )

escapeXml10 ( )

16. org.apache.commons.beanutils.BeanUtils

copyProperties ( )

getProperty ( )

setProperty ( )

describe ( )

populate ( )

copyProperty ( )

cloneBean ( )