maven中央仓库、远程仓库地址
1.http://repo1.maven.org/maven2 (官方,速度一般)
2.http://maven.aliyun.com/nexus/content/repositories/central/ (阿里云,速度快)
3.http://repository.jboss.com/maven2/
4.https://repository.sonatype.org/content/groups/public/
5.http://mvnrepository.com/