StringUtils.isBlank为null字符串返回false

Question

I am working in a Java project and my code shows weird behavior. Here is my code:

String access = String.valueOf(getStringvalue());
Boolean isBlank = StringUtils.isBlank(access);

In the above code, 'access' object can have null values. And it is said that if we pass a null value to StringUtils.isBlank() , it will return true. But here I returned only false value when access is null. What is the reason for this behavior?

Answer 1

I also had this problem and found the trick just after saw the source code of String.valueof(). The source code of String.valueof() is below.

public static String valueOf(Object obj) {
    return (obj == null) ? "null" : obj.toString();
}

Therefore when you pass a null object, you will get a 'null' String. Therefore your StringUtils.isBlank() will treat is as a String rather than a null object and you will get a 'false' booean value.

Hope it helps.!

Answer 2

I tested those code and they give the same result.

 Boolean isBlank = StringUtils.isBlank("");
 System.out.println(isBlank);// give true

and

 Boolean isBlank = StringUtils.isBlank(null);
 System.out.println(isBlank);// give true