Trimming a Blank String in Java

Question

I am trying to run a check to see if a string is just white space. I tried using trim like this:

if( dataIn[ i ].trim() == "" )
    {
        throw new MailRecordException( "Line: " + lineNumber + ", Field: "
            + fieldNumber + " :Blank Field" );
    }

But it never registers as true. How could I run a check to see if a string is only whitespace?

Per the duplicate question, you need to use `Object.equals(Object)` to compare `String`(s). But, for your **specific** case I would suggest you prefer [`String.isEmpty()`](http://docs.oracle.com/javase/8/docs/api/java/lang/String.html#isEmpty--), like `data[i].trim().isEmpty()`. — Elliott Frisch, Nov 18 '15 at 03:40

score 0 · Accepted Answer · answered Nov 18 '15 at 03:35

0

You should use

dataIn[ i ].trim().equals("")

instead of

dataIn[ i ].trim() == ""

== tests whether the two operands refer to the same object.

equals() (which can be overridden) compares the values of the two objects.

answered Nov 18 '15 at 03:35

Brian

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score 0 · Answer 2 · answered Nov 18 '15 at 03:35

0

Use equals instead of == for String comparison

dataIn[ i ].trim().equals("")

answered Nov 18 '15 at 03:35

Nyavro

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Ah, I feel stupid. Thanks – Sc0tty Nov 18 '15 at 03:36

score 0 · Answer 3 · answered Nov 18 '15 at 03:37

0

how about this?

if( dataIn[ i ].trim().length() == 0 ) //check for empty string
{
    throw new MailRecordException( "Line: " + lineNumber + ", Field: "
        + fieldNumber + " :Blank Field" );
}

answered Nov 18 '15 at 03:37

William Ku

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score 0 · Answer 4 · edited Nov 18 '15 at 03:56

0

dataIn[ i ].trim().length == 0

or

dataIn[ i ].trim().equals("")

edited Nov 18 '15 at 03:56

NaviRamyle

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answered Nov 18 '15 at 03:37

Rookie007

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Trimming a Blank String in Java

4 Answers4