今天把一个去年没做完的项目翻出来做时，发明maven无法正常导入依赖。查抄了一遍项目配置，，没发明有什么问题。而且依赖在本地货仓存在。

随后发明报错：Failed to transfer file:*********. Return code is: 501 , ReasonPhrase:HTTPS Required. 这时候仿佛发明了什么重点————我们需要将maven配置改削一下：

<!-- 中央货仓1 --> <mirror> <id>repo1</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>https://repo1.maven.org/maven2/</url> </mirror> <!-- 中央货仓2 --> <mirror> <id>repo2</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>https://repo2.maven.org/maven2/</url> </mirror>

随后发明可以正常导入依赖了。

在stackoverflow上查了下，发明有人也遇到了这个问题：

Recently Maven build jobs running in Jenkins are failing with the below exception saying that they could not pull dependencies from Maven Central and should use HTTPS. I am not sure how to change the requests from HTTP to HTTPS. Could someone guide me on this matter?

回答如下：

Effective January 15, 2020, The Central Repository no longer supports insecure communication over plain HTTP and requires that all requests to the repository are encrypted over HTTPS.

所以这个问题的泉源就是maven中央货仓此刻只撑持HTTPS协议，我们改一下就行。

maven报错：Return code is: 501 , ReasonPhrase:HTTPS Required