问题
I have an example Grails application (from Grails in Action) that was created a while ago under version 1.1.1 on a different PC.
I am now loading Grails 1.2.0 and want to revisit the app. However, when I try to run it I get this message:
Application expects grails version [1.1.1], but GRAILS_HOME is version [1.2.0] - use the correct Grails version or run 'grails upgrade' if this Grails version is newer than the version your application expects.
After reading around a bit I cleared out the 1.2.0 folder under .grails in my home directory (from previous attempts while exploring the issue), ran "grails clean" and "grails upgrade" (answering "y" where prompted).
However, I consistently get "Invalid duplicate class definition" conflicts between classes in \grails\qotd\src\java and \grails\qotd\grails-app{controllers,services,conf}.
Are there any additional manual steps that I need to perform?
回答1:
If, as you pointed out in the comments, your /src/java contains .groovy files - that could definitely cause unexpected behavior. I haven't hit your particular issue, but any time I had a .groovy file mismatched with the class name inside it, I'd get strange compilation issues - so I guess you could be having a similar issue.
If you have files / classes with the same names in two locations, that's the likely culprit. If you have .groovy files in /src/java, that's another potential source.
Also, putting BootStrap, Config, DataSource and URLMappings into /src/java, that's another potential source of issues. I'd clear out your /src/java by making sure all the files are in their appropriate places under grails-app.
回答2:
I understood your problem. The solution is just modify the grails vesion to 1.2.0 in application.properties file in your application
回答3:
You can upgrade grails version with 5 steps
- Project -> Clean
- application.properties -> Change app.grails.version
- Your project -> Properties -> Grails -> Change grails installation to new grails version.
- Your project -> Grails tools -> Refresh Dependencies
I think this may be help you
来源：https://stackoverflow.com/questions/2034023/how-do-i-upgrade-the-grails-version-for-an-existing-application