this is my build.gradle
repositories {
    mavenCentral()
    maven{url 'http://example.com/repository/maven-public/'}
}
dependencies {
    compile group: 'com.example', name: 'example-commlib', version: '1.0'
}
and the link http://example.com/repository/maven-public/ is build from Nexus Repository Manager which can accessable. 
and when I click Refresh Gradle Project in eclipse.
I can see the link is point to 
https://repo.maven.apache.org/..../example-commlib-1.0.pom
I think the right url is
http://example.com/repository/maven-public/.../example-commlib-1.0.pom
I've check the gradle setting and maven setting in eclipse. It seems fine.
So what's the problem?