Spring @Value annotation with List and default value

Question

I have a property in config file, which contains a list of values in such format. The format has to remain the same. myapp.values=value1,value2,value2

I use these values in my config class like that:

@Value("#{'{myapp.values}'.split(,)}")
private List<String> values;

My question is there a way to make a default value (empty list or null) it there is no such property in config file or the property is empty?

I tried to google this with no success. People either use myapp.values={value1,value2,value3} which doesn't suit me or format for that or use default values for simple variables, not lists.

My question is only about achieving the goal by changing the @Value annotation. Pls do not suggest workarounds

jcompetence · Accepted Answer · 2021-09-09 12:15:26Z

6

@Value("${myapp.values:}#{T(java.util.Collections).emptyList()}")
private List<String> defaultToEmpty;

or

@Value("#{T(java.util.Arrays).asList('${myapp.values:}')}")
private List<String> defaultToEmpty = new ArrayList();

answered Sep 9, 2021 at 12:15

jcompetence

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1 Comment

Rinkashikachi Over a year ago

For some reason first solution doesn't work in WildFly. If there are several values, it doesn't split them and takes whole string as the first element. Second solution works fine though. In Spring Boot both work.

Desmond Stonie · Accepted Answer · 2021-09-09 13:17:22Z

5

Actually, just one symbol : with an empty default value will work:

@Value("${myapp.values:}")
private List<String> values;

answered Sep 9, 2021 at 13:17

Desmond Stonie

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2 Comments

Rinkashikachi Over a year ago

Strange. This was my first guess, but there is info all over the internet, that if your list in property file is not in {1,2,3} format, then simple ${myapp.values} doesn't parse it correctly. That's why I didn't even try that and sticked with usage of split(,) which didn't allow to use : simple as that. Thank you, it works.

Rinkashikachi Over a year ago

For some reason this doesn't work in WildFly. If there are several values, it doesn't split them and takes whole string as the first element. In Spring Boot it works properly though.

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