索引地址
http://mvnrepository.com/
http://search.maven.org/
仓库下载地址：
https://repo1.maven.org/maven2/
https://repository.jboss.org/maven2/
https://repository.sonatype.org/content/groups/public/
http://maven.aliyun.com/nexus/content/groups/public
http://repo.springsource.org/libs-milestone-local
