old for andorid studio/gradle:
maven { url "http://maven.aliyun.com/nexus/content/groups/public/" }
new for andorid studio/gradle:
maven { url "https://maven.aliyun.com/repository/public/" }
檢視阿里雲倉庫列表：
https://maven.aliyun.com/mvn/view
阿里雲倉庫列表：
public repository
https://maven.aliyun.com/repository/public
google repository
https://maven.aliyun.com/repository/google
gradle-plugin repository
https://maven.aliyun.com/repository/gradle-plugin
jcenter repository
https://maven.aliyun.com/repository/jcenter
releases repository
https://maven.aliyun.com/repository/releases
spring repository
https://maven.aliyun.com/repository/spring
spring-plugin repository
https://maven.aliyun.com/repository/spring-plugin
說明：
public庫是group庫，其實代理了maven central和jcenter倉庫
你可以瀏覽proxy庫central或jcenter的內容，凡是裡面有的包都可以通過public庫下載。