Empty Threadcontext braces scenario handling in log4j2

Question

I am trying to migrate to log4j2. In RollingFile Appender I am adding as below:

<PatternLayout>
    <pattern>[%d{MM/dd/yy HH:mm:ss:SSS z}] %-18.18t %-35.35c{1} %-5p (%F:%L) %m \t %x %n</pattern>
</PatternLayout>

We know that %x is for printing stack elements to end of the every logger statement.

Now if my stack is empty initially, it is giving me the empty braces as below.

[01/10/17 12:17:37:116 IST] main               Example2                            WARN  (Example2.java:52) 10 is the number     []

[01/10/17 12:17:37:116 IST] main Example2 WARN (Example2.java:52) 10 is the number []

So how do I handle this empty stack scenario ?

I want the logger without braces as below. `[01/10/17 12:17:37:116 IST] main Example2 WARN (Example2.java:52) 10 is the number` — user3207875, Jan 10 '17 at 12:29

score 2 · Answer 1 · answered Jan 10 '17 at 16:39

2

You can use PatternLayout's notEmpty{pattern} pattern converter:

This outputs the result of evaluating the pattern if and only if all variables in the pattern are not empty.

For example:

%notEmpty{[%x]}

Aliases: variablesNotEmpty{pattern}, varsNotEmpty{pattern}, notEmpty{pattern}

answered Jan 10 '17 at 16:39

Remko Popma

1

This will not work. Its taking `%notEmpty{[%x]}` as **%n** and takes the logger to next line. – user3207875 Jan 11 '17 at 05:06
What version are you using? This feature is fairly recent. Have you tried `varsNotEmpty`? – Remko Popma Jan 11 '17 at 06:45
Version 2.7? Or something older? – Remko Popma Jan 11 '17 at 06:53
Now the ouput logger is `[01/11/17 12:22:59:693 IST] main Example2 DEBUG (Example2.java:56) 10 is the number otEmpty` – user3207875 Jan 11 '17 at 06:54
Can't migrate to v2.7 as can't go beyond Java 6. Hence I am using log4j v2.3 – user3207875 Jan 11 '17 at 06:55
Ouch. %notEmpty doesn't exist in 2.3. You can backport as a custom plugin. Just take the source & compile in your project. – Remko Popma Jan 11 '17 at 06:57

score 1 · Answer 2 · answered May 29 '23 at 15:47

1

For example -

%equals{%x}{[]}{}

This will replace [] with empty string. Worked for me.

answered May 29 '23 at 15:47

Vaishnavi Rathi

2 Answers2