Android studio下载第三方库下载不下来，或者很慢

allprojects {
    repositories {
//        maven{ url'http://maven.aliyun.com/nexus/content/groups/public/' }
//        maven { url 'http://developer.huawei.com/repo/' }
        maven { url 'https://maven.aliyun.com/repository/google' }
        maven { url 'https://maven.aliyun.com/repository/jcenter' }
        google()
        jcenter()
    }
}