How can I check whether a string is not null and not empty?
public void doStuff(String str)
{
if (str != null && str != "**here I want to check the 'str' is empty or not**")
{
/* handle empty string */
}
/* ... */
}
javastringstring-comparison
How can I check whether a string is not null and not empty?
public void doStuff(String str)
{
if (str != null && str != "**here I want to check the 'str' is empty or not**")
{
/* handle empty string */
}
/* ... */
}
Best Answer
What about isEmpty() ?
Be sure to use the parts of
&&
in this order, because java will not proceed to evaluate the second part if the first part of&&
fails, thus ensuring you will not get a null pointer exception fromstr.isEmpty()
ifstr
is null.Beware, it's only available since Java SE 1.6. You have to check
str.length() == 0
on previous versions.To ignore whitespace as well:
(since Java 11
str.trim().isEmpty()
can be reduced tostr.isBlank()
which will also test for other Unicode white spaces)Wrapped in a handy function:
Becomes: