Set version of javascript file. Java EE + Tomcat

Question

By adding updates to javascript and css I want to avoid to force users to press Ctrl+F5 to refresh cached js and css files.

Disabling cache is not a choise too.

For this I suppose to add version to js and css links like this

< link href="~/CSS/file.css?MY_VERSION" rel="stylesheet" />

Ideally version has to be something like build number of build date and time.
But how can I set this automatically?

I do not want to update this values at all jsp files manually after every update. So questions are

can maven add build version to jsp files?
if first point is not possible how (and where) can I set application global variable with current date and time? For example I cannot put it into servlet because it is constructed with every request.
What are best practices for do this? Maybe my approach is totally incorrect

score 2 · Accepted Answer · edited May 23 '17 at 12:13

Yes, we do something similar (for image references in css files):

<plugin>
    <groupId>com.google.code.maven-replacer-plugin</groupId>
    <artifactId>maven-replacer-plugin</artifactId>
    <version>1.4.1</version>
    <executions>
        <execution>
            <id>anticache</id>
            <phase>prepare-package</phase>
            <goals>
                <goal>replace</goal>
            </goals>
            <configuration>
                <includes>
                    <include>target/classes/**/*.css</include>
                </includes>
                <replacements>
                    <replacement>
                        <token>anti-cache=anti-cache-parameter</token>
                        <value>anti-cache=${maven.build.timestamp}</value>
                    </replacement>
                </replacements>
            </configuration>
        </execution>
    </executions>
</plugin>

Just check the file pattern to match your JS files and then in your JS files:

< link href="~/CSS/file.css#anti-cache=anti-cache-parameter" rel="stylesheet" />

Note that I don't use a request parameter (?) here but #. This is to avoid that the browser cache will be impacted since with a request parameter the browser cache will hang on to each version of the file. See also: Refresh image with a new one at the same url

Now, as said, we use this but it's not an ideal solution either but then I don't think an ideal solution exists.

Also see the behavior of caching in different browsers: https://github.com/podlipensky/RefreshButton

Set version of javascript file. Java EE + Tomcat

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