String isNullOrEmpty in Java? [duplicate]

Answer 1

com.google.common.base.Strings.isNullOrEmpty(String string) from Google Guava

Answer 2

In addition to the other answers, I ran across this because I'm a C# programmer primarily, but trying to keep fresh in Java. I noticed that when I tried to use StringUtils my IDE (Eclipse) imported it from com.mysql.jdbc.StringUtils which actually has an isNullOrEmpty(myStringObject) method.

ex.

import com.mysql.jdbc.StringUtils;

StringUtils.isNullOrEmpty(host)

Just another alternative for those who already have the MySQL connector referenced in your project, but not the other StringUtils library.

Answer 3

public static boolean isNull(String str) {
        return str == null ? true : false;
    }

    public static boolean isNullOrBlank(String param) {
        if (isNull(param) || param.trim().length() == 0) {
            return true;
        }
        return false;
    }

Answer 4

• StringUtils.isEmpty(str) or StringUtils.isNotEmpty(str)
• StringUtils.isBlank(str) or StringUtils.isNotBlank(str)

from Apache commons-lang.

The difference between empty and blank is : a string consisted of whitespaces only is blank but isn't empty.

I generally prefer using apache-commons if possible, instead of writing my own utility methods, although that is also plausible for simple ones like these.

Answer 5

For new projects, I've started having every class I write extend the same base class where I can put all the utility methods that are annoyingly missing from Java like this one, the equivalent for collections (tired of writing list != null && ! list.isEmpty()), null-safe equals, etc. I still use Apache Commons for the implementation but this saves a small amount of typing and I haven't seen any negative effects.

Answer 6

No, which is why so many other libraries have their own copy :)