What does log4j2 file appenders use for file encoding/format?

Question

What file format does log4j2 use when it writes to rollingfileappender? Furthermore, is there a way to change it? What I'd like to do use use UTF-16.

Seeing

Answer 1

The Charset is specified on the Layout. AbstractStringLayout defaults to UTF-8.

You should be able to change that by specifying charset="UTF-16" on the Layout configuration.

Hamadryad

Thank you! It did not occur to me it was part of the pattern as I was looking all over the appenders for it. Information on layouts are here – Seeing

+10. It may be worth pointing out that most layouts including PatternLayout extend AbstractStringLayout so they all accept a charset parameter. – Rik

You are right! It works in my log4j2.xml <PatternLayout pattern="<mypattern>" charset="UTF-8" /> – Jetport

Answer 2

Small correction on Ralph's answer: for PatternLayout the default charset is the system default. This is important because for example the Windows console won't be able to correctly display UTF-8 on Japanese Windows.

Rik

Answer 3

If you use log4j.properties, configure it as follow:

appender.rolling.layout.charset = UTF-16

or make the corresponding configurations in your xml configuration file.

Littell

You should provide a larger excerpt of your configuration, because the current content of your answer can give the wrong impression that appender.rolling.layout.charset is a universally valid configuration property. In reality rolling and layout are arbitrary identifiers. – Repugnance