Checking if a string is empty or null in Java

Question

I m parsing HTML data   The String may be null or empty  when the word to parse does not match   So  I wrote it like this   if string equals null     string equals           Log d  iftrue    seem to be true     else      Log d  iffalse    seem to be false        When I delete String equals      it does not work correctly    I thought String equals     wasn t correct   How can I best check for an empty String

User · Answer

You can use Apache commons-lang   StringUtils isEmpty String str   - Checks if a String is empty      or null   or  StringUtils isBlank String str   - Checks if a String is whitespace  empty      or null   the latter considers a String which consists of spaces or special characters eg     empty too  See java lang Character isWhitespace API

User · Answer

Correct way to check for null or empty or string containing only spaces is like this  if str    null  amp  amp   str trim   isEmpty         do your stuffs here

User · Answer

import com google common base  if  Strings isNullOrEmpty String str           Do your stuff here

User · Answer

You can leverage Apache Commons StringUtils isEmpty str   which checks for empty strings and handles null gracefully   Example   System out println StringUtils isEmpty          true System out println StringUtils isEmpty null       true   Google Guava also provides a similar  probably easier-to-read method   Strings isNullOrEmpty str    Example   System out println Strings isNullOrEmpty          true System out println Strings isNullOrEmpty null       true

User · Answer

This way you check if the string is not null and not empty  also considering the empty spaces   boolean isEmpty   str    null    str trim   length      0  if  isEmpty           handle the validation

[java] Checking if a string is empty or null in Java

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