如何使用Gradle将原生依赖项添加到Java项目中

Question

I am working on a project using opencv. I have successfully created the required jar and native libs for macOS platform. I now want to use this in my java project. I am using gradle for build and dependency management. I have added the jar and native dependency in lib folder of my project.

build.gradle

group 'com.udaykale'
version '1.0-SNAPSHOT'

apply plugin: 'java'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile(
            files('lib/opencv-320.jar')
    )
    testCompile group: 'junit', name: 'junit', version: '4.11'
}

System.setProperty("java.library.path", "lib")

I am getting the following error:

Exception in thread "main" java.lang.UnsatisfiedLinkError: no opencv_java320 in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1867)
    at java.lang.Runtime.loadLibrary0(Runtime.java:870)
    at java.lang.System.loadLibrary(System.java:1122)
    at com.udaykale.imageeditor.Main.<clinit>(Main.java:13)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)

I understand that I the native library is not visible at runtime. How do I change my gradle config to handle this?

Answer 1

Local install the opencv-320.jar file with maven and use it as a dependency in your build.gradle.To local install the artifact use following command. Specify the version, group id and artifact id accordingly.

mvn install:install-file -Dfile=<path-to-file> -DgroupId=<group-id> 
-DartifactId=<artifact-id> -Dversion=<version> -Dpackaging=jar

Also add local repositories to build.gradle

repositories {
 mavenLocal()
}

And then the dependency

dependencies {
 compile "<group-id>:<artifact-id>:<version>"
}