Java: How to assign to a variable if the result is null?

Question

This works:

String address1 = HtmlUtil.escape(rs.getString("address1"));

...but i don't want to display "null". So i tried this, which does not work:

String address1 = HtmlUtil.escape(rs.getString("address1") || "");

Is the best option to use this:?

String address1 = HtmlUtil.escape(rs.getString("address1"));
if (address1 == null) address1 = "";

Juvanis · Accepted Answer · 2012-12-18 09:51:24Z

6

Using ternary operator, you can assign a value with single line of code:

String address1 = (rs.getString("address1") != null) ?
                  HtmlUtil.escape(rs.getString("address1")) : "";

answered Dec 18, 2012 at 9:51

Juvanis

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3 Comments

FThompson Over a year ago

It's bad practice to make identical calls to a method (here, rs.getString); use a temporary variable instead.

Juvanis Over a year ago

@Vulcan I just wanted to give an idea to the OP. Of course he/she can use temporary variable for it. but this has nothing to do with the accuracy of my answer and you shouldn't have downvoted.

Cees Timmerman Over a year ago

I like the ternary operator but in this case my solution is shorter, more readable, and more efficient.

Tom Verelst · Accepted Answer · 2012-12-18 09:52:23Z

4

String address1 = HtmlUtil.escape(rs.getString("address1"));
if (address1 == null || address1.equals("null")) {
    address1 = "";
}

answered Dec 18, 2012 at 9:52

Tom Verelst

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4 Comments

Cees Timmerman Over a year ago

Because the database also contained bad strings, i'll accept this answer.

Tom Verelst Over a year ago

If you have multiple variables you have to get from your ResultSet and you need to check for null (or "null"), I would suggest to write a method you can reuse for other variables and perhaps wrap this in a ResultSetWrapper so you keep your code clean.

Tom Verelst Over a year ago

I would also suggest your get rid of the "null" strings in your database / application. It is an unnecessary overhead.

Cees Timmerman Over a year ago

That was actually a mistake (i didn't realize the escape function would not escape the null), but the field can contain whitespace and i always forget about having to use equals() to reliably compare strings in Java.

Petr Mensik · Accepted Answer · 2012-12-18 09:51:43Z

1

String address1 = HtmlUtil.escape(rs.getString("address1")) == null ? "" : HtmlUtil.escape(rs.getString("address1"));

If you want ugly one-liner:-)

answered Dec 18, 2012 at 9:51

Petr Mensik

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Comments

Atropo · Accepted Answer · 2012-12-18 10:03:31Z

1

Solution:

 String address1 = HtmlUtil.escape(rs.getString("address1"));
 if (address1 == null) address1 = "";

edited Dec 18, 2012 at 10:03

Atropo

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answered Dec 18, 2012 at 9:58

Nipun Jain

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1 Comment

Cees Timmerman Over a year ago

I suppose this is the most efficient solution.

Cees Timmerman · Accepted Answer · 2014-09-16 10:56:16Z

1

Use a temp variable to only call HtmlUtil.escape once. Then check for null and assign to address1:

String tempAddress =  HtmlUtil.escape(rs.getString("address1"));
String address1 = tempAddress != null ? tempAddress : "";

edited Sep 16, 2014 at 10:56

Cees Timmerman

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answered Dec 18, 2012 at 9:55

someone

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1 Comment

Cees Timmerman Over a year ago

I'd rather not create additional variables.

Muhammad Imran Tariq · Accepted Answer · 2012-12-18 09:55:17Z

0

Try something like this

<c:when test="${empty rs.getString("address1")}">
  ...
</c:when>
<c:otherwise>
   .....
</c:otherwise>

answered Dec 18, 2012 at 9:55

Muhammad Imran Tariq

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Comments

Jubin Patel · Accepted Answer · 2012-12-18 13:07:39Z

0

you can try this :

String address1 = "";
if(HtmlUtil.escape(rs.getString("address1") != null && !(HtmlUtil.escape(rs.getString("address1").equalsIgnoreCase("null"))){
address1 = HtmlUtil.escape(rs.getString("address1"));
}

edited Dec 18, 2012 at 13:07

answered Dec 18, 2012 at 12:48

Jubin Patel

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1 Comment

Cees Timmerman Over a year ago

You really don't have to call and escape thrice, but that does look like my final code: if (address1 != null && address1 != "") address_tip += address1+"
";

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