StringUtils的使用,数组转list,list转数组

数组转list:

1)、方法1:
String[] userid = {“aa”,”bb”,”cc”};
List userList = new ArrayList();
Collections.addAll(userList, userid);
2)、方法2:
String[] userid = {“aa”,”bb”,”cc”};
List userList = Arrays.asList(userid);
另:Arrays.asList()返回一个受指定数组支持的固定大小的列表。所以不能做Add、Remove等操作。
List list = new ArrayList(Arrays.asList(userid));这样操作就可以了。

StringUtils的使用

:自己写String的处理繁琐,这些常用工具都有:
参考官网
StringUtils官网

<dependency>
   <groupId>commons-langgroupId>
   <artifactId>commons-langartifactId>
   <version>2.6version>
dependency>
  • IsEmpty/IsBlank - checks if a String contains text
  • Trim/Strip - removes leading and trailing whitespace
  • Equals - compares two strings null-safe
  • startsWith - check if a String starts with a prefix null-safe
  • endsWith - check if a String ends with a suffix null-safe
  • IndexOf/LastIndexOf/Contains - null-safe index-of checks
  • IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut - index-of any of a set of Strings
  • ContainsOnly/ContainsNone/ContainsAny - does String contains only/none/any of these characters
  • Substring/Left/Right/Mid - null-safe substring extractions
  • SubstringBefore/SubstringAfter/SubstringBetween - substring extraction relative to other strings
  • Split/Join - splits a String into an array of substrings and vice versa
  • Remove/Delete - removes part of a String
  • Replace/Overlay - Searches a String and replaces one String with another
  • Chomp/Chop - removes the last part of a String
  • LeftPad/RightPad/Center/Repeat - pads a String
  • UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize - changes the case of a String
  • CountMatches - counts the number of occurrences of one String in another
  • IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable - checks the characters in a String
  • DefaultString - protects against a null input String
  • Reverse/ReverseDelimited - reverses a String
  • Abbreviate - abbreviates a string using ellipsis
  • Difference - compares Strings and reports on their differences
  • LevensteinDistance - the number of changes needed to change one String into another

MapUtils、CollectionUtils等的使用:

这个jar包的功能很像jdk中的Collection的功能,可以认为是它的扩充,有各种常用的map,set,list,Collection等的各种常用方法, 加速你的编码过程,而且这些东西,是比较官方的,是经得起考验的,比自己匆忙之下写的肯定要优雅好多,要多学多用。

参考官网:
MapUtils、CollectionUtils等的使用

<dependency>
  <groupId>commons-collectionsgroupId>
  <artifactId>commons-collectionsartifactId>
  <version>3.2.1version>
dependency>

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