The difference between isEmpty and isBlank

isEmpty   judges whether a string is empty. The standard for being empty is str==null or str.length()==0

    StringUtils.isEmpty(null) = true

　　StringUtils.isEmpty("") = true
　　StringUtils.isEmpty(" " ) = false//Note that spaces are treated as non-empty in 
　　StringUtils StringUtils.isEmpty(" ") = false
　　StringUtils.isEmpty("bob") = false
　　StringUtils.isEmpty(" bob ") = false

isBlank    determines whether a string is Empty or length 0 or consisting of whitespace

   StringUtils.isBlank(null) = true

　　StringUtils.isBlank("") = true
　　StringUtils.isBlank(" ") = true
　　StringUtils.isBlank(" ") = true
　　StringUtils. isBlank("\t \n \f \r") = true //For tabs, newlines, form feeds and carriage returns 
　　StringUtils. 
　　StringUtils.isBlank("\b") = false //"\b" is the word boundary character 
　　StringUtils.isBlank("bob") = false
　　StringUtils.isBlank("bob ") = false