在不能添加本地Maven回购的情况下，如何在Maven项目（编译，构建，打包）中包含第3方jars？

Question

We have a git project that has some 3rd party jars which are not available in any Maven repo and are in a "lib" folder in the project. I need to include them for compiling, building and then package them into the WAR in WEB-INF/lib .

I cannot add them as a local maven repo from the command line because this projects needs to be buildable for anyone cloning the repo without requiring them to run extra commands (I have no way around this requirement).

I saw some people suggesting System scope but that then Maven won't package them into your WAR:

<dependency>
    <groupId>com.roufid.tutorials</groupId>
    <artifactId>example-app</artifactId>
    <version>1.0</version>
    <scope>system</scope>
    <systemPath>${basedir}/lib/yourJar.jar</systemPath>
</dependency>

How do I get these jars to be used for compiling/inspection, building and then packaged into the WAR?

Answer 1

You can use :

• System scope but make the packaging yourself via assembly plugin
• A maven repo along with your project (ie maven repo on-the-fly, basically same as local repo but without having a extra moving part to worry about because this repo follows your project).

For Maven repo on-the-fly option, you can do as described here (which is, take any already existing Maven repo, which already contains your needed jars, such as your local one, put it in your project, and then reference this repo from your project using relative paths).

Answer 2

I'll assume you've verified that whatever mechanism you might use to distribute these jars would be in compliance with the relevant licenses. If it would, then it seems there would be little reason for the jars' creators not to provide for official Maven distribution, so your best option might be to lobby for them to do that. But if not, and yet for some reason they'll allow for you distributing the jar (either through cloning of your repo, or via a separate Maven repo you maintain):

There are several ways. I give preference to approaches that don't put the jars in the git repo.

Publish a Maven Repo

So it's possible to host a public-facing repo and serve the artifacts that way. The pom can add your public-facing repo to the build, so that those who clone can build without having to run any special commands.

Running your own repo isn't terribly difficult. The OSS versions of Nexus or Artifactory jFrog would probably be perfectly capable.

But, if we're assuming the authors' refusal to publish their own jars via Maven means they don't want them distributed that way, then there's no reason to spend much time on the details of this option. So moving on...

Distribution in the Git Repo

I guess this is what you're doing, though again if Maven distribution violates the license I'd make sure you're splitting hairs the right way in thinking that this doesn't.

So the question would be how to get Maven to deal with the artifacts distributed in this way, and again there are some options.

Your objection to putting the jars in the local repo is that it would require extra commands of the user; but actually this could be automated in the "validate" phase of the build. Binding install:install-file to the validate phase should work.

Alternately, your objection to using system scope is that the file isn't copied into the final war. You might be able to use the dependency plugin to force the issue, but I'm not sure of that. What I am sure of is you could treat the directory containing the jars as a web resource with suitable configuration in the war plugin. (You'd want it to be treated as unfiltered and to map to the WEB-INF/lib folder.)

In any case, if you distribute jars (or other large binaries) in the git repo, I strongly recommend you look at git lfs . This will require one-time configuration by each of your users, but it will prevent your repo from gradually becoming bloated and unusable.

Answer 3

Use forward slash (/) to backslash () in the systemPath.

<dependency>
<groupId>com.roufid.tutorials</groupId>`enter code here`
<artifactId>example-app</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${basedir}\lib\yourJar.jar</systemPath>