迁移Ant Gradle - Eclipse中的类路径和Buildpath问题

Question

Current situation: I am migrating a build system from Ant to Gradle. Currently I'm facing an issue with the classpath and buildpath. Here is the current Ant compile target definition:

    <target name="compile">
        <mkdir dir="${build.compile.target}/classes" />
        <javac srcdir="${src}" destdir="${build.compile.target}/classes">
            <classpath>
                <fileset dir="${build.war}/WEB-INF/lib">
                    <include name="**/*.jar" />
                </fileset>
                <pathelement location="${build.war}/WEB-INF/classes" />
            </classpath>
        </javac>
    </target>

The developers usually execute the following setup-local target to build the war files, etc.

<target name="setup-local" depends="clean">
    <antcall target="copy_webapp" />
    <antcall target="compile" />

The copy_webapp target is copying .jar and .class files from a directory into the ${build.war} directory. Unfortunately this copy target is really needed as it makes relevant modifications to the files (it's merging files from two directories into one, does overwriting and file modifications. It's legacy code without any comments. I really don't want to do research on it and find out why things are how they are)

The problem for me: In the classpath there is a reference on files which do only exist when the copy_webapp target is executed beforehand. Fair enough - This works if I always execute the setup-local target only.

Now after migrating to Gradle and importing the project to Eclipse, I get thousands of errors in my .java files, saying the imports cannot be resolved. Well, of course not. In the buildpath are files (fe "${build.war}/path/to/jar") that are not existing.

I don't know how to solve these errors. Do I need to restructure my classpath so that there is no dependency on the copy_webapp target before? Or can I modify the buildpath somehow (with Gradle) that it first has to resolve the copy_webapp target before?

Answer 1

Given the information it's hard to get at the root of your problem.

One option is to create a "staging" directory for the Eclipse project when you have a Gradle task that is generating a complex directory structure and/or intermediate output needed by Eclipse deploy your project.

The way I tackle this is by creating a sub-task that is run when calling gradle eclipse . Add the line it.dependsOn eclipse in the configuration of the task. The output of this task would go into build/eclipse/TaskName or some descriptive location in the build/ dir. The classpath references should then be updated to point to the output directory location under your build/ dir.

Also, you might have to post-process the classpath entries that the eclipse task is using to generate the project classpath so they correctly reference task output location.