StringUtils.isBlank()
method check to see is the string contains only whitespace characters, empty or has a null value. If these conditions are true the strings are considered blank.
There’s also a StringUtils.isEmpty()
, only this method doesn’t check for whitespaces-only string. For checking the opposite condition there are StringUtils.isNotBlank()
and StringUtils.isNotEmpty()
.
Using these methods we can avoid repeating the code for checking empty string which can include more code to type then using these handy methods.
package org.kodejava.commons.lang;
import org.apache.commons.lang3.StringUtils;
public class CheckEmptyString {
public static void main(String[] args) {
String var1 = null;
String var2 = "";
String var3 = " \t\t\t";
String var4 = "Hello World";
System.out.println("var1 is blank? = " + StringUtils.isBlank(var1));
System.out.println("var2 is blank? = " + StringUtils.isBlank(var2));
System.out.println("var3 is blank? = " + StringUtils.isBlank(var3));
System.out.println("var4 is blank? = " + StringUtils.isBlank(var4));
System.out.println("var1 is not blank? = " + StringUtils.isNotBlank(var1));
System.out.println("var2 is not blank? = " + StringUtils.isNotBlank(var2));
System.out.println("var3 is not blank? = " + StringUtils.isNotBlank(var3));
System.out.println("var4 is not blank? = " + StringUtils.isNotBlank(var4));
System.out.println("var1 is empty? = " + StringUtils.isEmpty(var1));
System.out.println("var2 is empty? = " + StringUtils.isEmpty(var2));
System.out.println("var3 is empty? = " + StringUtils.isEmpty(var3));
System.out.println("var4 is empty? = " + StringUtils.isEmpty(var4));
System.out.println("var1 is not empty? = " + StringUtils.isNotEmpty(var1));
System.out.println("var2 is not empty? = " + StringUtils.isNotEmpty(var2));
System.out.println("var3 is not empty? = " + StringUtils.isNotEmpty(var3));
System.out.println("var4 is not empty? = " + StringUtils.isNotEmpty(var4));
}
}
The result of our program are:
var1 is blank? = true
var2 is blank? = true
var3 is blank? = true
var4 is blank? = false
var1 is not blank? = false
var2 is not blank? = false
var3 is not blank? = false
var4 is not blank? = true
var1 is empty? = true
var2 is empty? = true
var3 is empty? = false
var4 is empty? = false
var1 is not empty? = false
var2 is not empty? = false
var3 is not empty? = true
var4 is not empty? = true
Maven Dependencies
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.12.0</version>
</dependency>
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Have you ever run the program once?
var3 is blank? = true
This is incorrect. By the way, you should use commons-lang3 instead of the older version.