从messages.properties访问application.properties

Question

I need to access properties from application.properties in messages.properties:

application.properties

max-size=3

messages.properties

alert.error=You can only save {max-size} items.

Not working:

{max-size}, #{max-size}, ${max-size}

I am aware of this thread, but I need it outside of any Java file.

Update: the maven approach works within application.properties files but not between application.properties and messages.properties. Shouldn't there be an order? If file A has key a but when file B is parsed first a is not available in B yet, is it?

Snippet from my pom.xml:

<build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
                <includes>
                    <include>**/*.properties</include>
                </includes>
            </resource>

"#{alert.error(${@environment.getProperty('max-size')})}"

Answer 1

Either you replace it using build tools (Maven/Gradle/...), or you use a parameter in your message, like this:

alert.error=You can only save {0} items.

Now you can autowire your MessageSource and retrieve your maxSize :

@Autowired
private MessageSource messageSource;
@Value("${max-size}")
private int maxSize;

And then you can use it this way:

messageSource.getMessage("alert.error", new Object[]{maxSize}, locale);

This solution allows you to use your message for other sizes as well, rather than making it just 3.

If you want to use it in your views (eg. with Thymeleaf), you can do:

<p th:text="#{alert.error(${@environment.getProperty('max-size')})}"></p>

Answer 2

If you're building in maven you can filter the message.properties at build time.

https://maven.apache.org/plugins/maven-resources-plugin/examples/filter.html

Answer 3

you can do via maven by invoking a resource plugin goal https://maven.apache.org/plugins/maven-resources-plugin/examples/filter.html

where messages.properties is placed in src/main/resources

<build>
        <filters>
            <filter>src/main/resources/application.properties</filter>
        </filters>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

invoke mvn resources:resources