In Java the StringUtils tool class resolves the judgment that String is null
- 2020-12-20 03:33:08
- OfStack
The criterion for determining whether a string is null is str==null or str.length ()==0
1. The following is an example of StringUtils judging whether it is empty:
StringUtils.isEmpty(null) = true
StringUtils.isEmpty("") = true
StringUtils.isEmpty(" ") = false // Note that in StringUtils The space in is treated as non-null
StringUtils.isEmpty(" ") = false
StringUtils.isEmpty("bob") = false
StringUtils.isEmpty(" bob ") = false
2. public static boolean isNotEmpty(String str)
Determines whether a string is non-null, equal to! isEmpty(String str)
Here is an example:
StringUtils.isNotEmpty(null) = false
StringUtils.isNotEmpty("") = false
StringUtils.isNotEmpty(" ") = true
StringUtils.isNotEmpty(" ") = true
StringUtils.isNotEmpty("bob") = true
StringUtils.isNotEmpty(" bob ") = true
3. public static boolean isBlank(String str)
Determines whether a string is null or has a length of 0 or consists of a blank character (whitespace)
Here is an example:
StringUtils.isBlank(null) = true
StringUtils.isBlank("") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank("\t \n \f \r") = true // For tabs, line feeds, page breaks, and carriage returns
StringUtils.isBlank() // Recognition is a blank character
StringUtils.isBlank("\b") = false //"\b" Is the word boundary character
StringUtils.isBlank("bob") = false
StringUtils.isBlank(" bob ") = false
4. public static boolean isNotBlank(String str)
Determines whether a string is not null and has a length of 0 and is not formed by a blank character (whitespace), equal to! isBlank(String str)
Here is an example:
StringUtils.isNotBlank(null) = false
StringUtils.isNotBlank("") = false
StringUtils.isNotBlank(" ") = false
StringUtils.isNotBlank(" ") = false
StringUtils.isNotBlank("\t \n \f \r") = false
StringUtils.isNotBlank("\b") = true
StringUtils.isNotBlank("bob") = true
StringUtils.isNotBlank(" bob ") = true
conclusion
This is all about the StringUtils tool class in Java for String null judgment parsing, I hope to help you. Interested friends can continue to refer to other related topics in this site, if there is any deficiency, welcome to comment out. Thank you for your support!