regex101: Spring Boot default log parser regex

^start of line

Group 1(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}(?:Z|[+-]\d{2}:\d{2}))

\d{4}a Unicode decimal digit, repeated exactly 4 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

Tthe literal T (84₁₀ / 124₈ / 54₁₆) (case sensitive)

\d{2}a Unicode decimal digit, repeated exactly 2 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

.any Unicode character (except for line terminators)

\d{3}a Unicode decimal digit, repeated exactly 3 times

Non-Capturing Group(?:Z|[+-]\d{2}:\d{2})

1st AlternativeZ

Zthe literal Z (90₁₀ / 132₈ / 5A₁₆) (case sensitive)

2nd Alternative[+-]\d{2}:\d{2}

Character Class[+-]

+the literal + (43₁₀ / 53₈ / 2B₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

\s*a Unicode whitespace character, repeated any number of times

Group 2(\w+)

\w+a Unicode word character, repeated at least once

\s*a Unicode whitespace character, repeated any number of times

Group 3(\d*)

\d*a Unicode decimal digit, repeated any number of times

\s*a Unicode whitespace character, repeated any number of times

---the literal text ---

\s*a Unicode whitespace character, repeated any number of times

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

\s*a Unicode whitespace character, repeated any number of times

Group 4([a-zA-Z0-9\._-]+)?

?repeats the group contents below at most once:

Character Class[a-zA-Z0-9\._-]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

\s*a Unicode whitespace character, repeated any number of times

Group 5([^\s]+)

Negated Character Class[^\s]+

+matches at least one character outside the set below:

\sa Unicode whitespace character

\s*a Unicode whitespace character, repeated any number of times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\s*a Unicode whitespace character, repeated any number of times

Group 6([^\n]+)

Negated Character Class[^\n]+

+matches at least one character outside the set below:

\na line-feed (newline) character (ASCII 10)

$end of line

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

g modifier: global. Finds all matches instead of stopping after the first

Search reference

Regular Expression

^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}(?:Z|[+-]\d{2}:\d{2}))\s*(\w+)\s*(\d*)\s*---\s*\[\s*([a-zA-Z0-9\._-]+)?\]\s*([^\s]+)\s*:\s*([^\n]+)$

New

2023-02-13T20:51:06.372+05:30  INFO 28357 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication using Java 17.0.2 with PID 28357 (/Users/snehangshub/Documents/Experiments/demo/build/classes/java/main started by snehangshub in /Users/snehangshub/Documents/Experiments/demo)
2023-02-13T20:51:06.373+05:30  INFO 28357 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to 1 default profile: "default"
2023-02-13T20:51:06.715+05:30  INFO 28357 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-02-13T20:51:06.721+05:30  INFO 28357 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-02-13T20:51:06.721+05:30  INFO 28357 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.5]
2023-02-13T20:51:06.763+05:30  INFO 28357 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-02-13T20:51:06.764+05:30  INFO 28357 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 371 ms
2023-02-13T20:51:06.899+05:30  INFO 28357 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-02-13T20:51:06.903+05:30  INFO 28357 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 0.684 seconds (process running for 0.832)
2023-02-13T20:51:24.855+05:30  INFO 28357 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2023-02-13T20:51:24.855+05:30  INFO 28357 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2023-02-13T20:51:24.858+05:30  INFO 28357 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 2 ms
2023-02-13T19:09:07.379Z  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''

Regular Expressions 101

Regular Expression

Extraction