logging - 如何格式化log4j2中的stacktrace？

Question

默认情况下，log4j2在多行上打印stacktrace，并用newline字符分隔。就像是:

java.lang.NullPointerException: error enovountered
    at ...
    at ...
    at ...

我希望我的stacktrace在单行上，类似，基本上是使用 |作为分隔符而不是 \n

java.lang.NullPointerException: error enovountered at ... | at ... | at ...

如何在log4j2中完成类似的操作？

Answer 1

如 PatternLayout documentation所指定，转换键的%throwable系列实际上是support being able to change the separator used for individual stack trace elements, as well as the "cause" exceptions。

给定一个像这样的模式:

[%threadName] %-5level %logger{36} - %message{nolookups}%xThrowable{separator(|)}%n

您将获得如下输出:

[main] ERROR my.cool.Application - Catching java.lang.RuntimeException: I'm wrapping the NPE|   at my.cool.Application.main(Application.java:24) [main/:?]|Caused by: java.lang.NullPointerException: This is a forced NPE| at java.util.Objects.requireNonNull(Objects.java:228) ~[?:1.8.0_121]|   at my.cool.Application.main(Application.java:21) ~[main/:?]