1.对于所有的项目来说，我们最好配置全局变量

在gradle文件夹下找到init.d文件夹。
查看有没有init.gradle文件，没有就直接创建，添加以下内容：

allprojects{
    repositories {
        def ALIYUN_REPOSITORY_URL = 'http://maven.aliyun.com/nexus/content/groups/public'
        def ALIYUN_JCENTER_URL = 'http://maven.aliyun.com/nexus/content/repositories/jcenter'
        all { ArtifactRepository repo ->
            if(repo instanceof MavenArtifactRepository){
                def url = repo.url.toString()
                if (url.startsWith('https://repo1.maven.org/maven2')) {
                    project.logger.lifecycle "Repository ${repo.url}</span> replaced by <span class="hljs-variable">$ALIYUN_REPOSITORY_URL."
                    remove repo
                }
                if (url.startsWith('https://jcenter.bintray.com/')) {
                    project.logger.lifecycle "Repository ${repo.url}</span> replaced by <span class="hljs-variable">$ALIYUN_JCENTER_URL."
                    remove repo
                }
            }
        }
        maven {
                url ALIYUN_REPOSITORY_URL
            url ALIYUN_JCENTER_URL
        }
    }
}