今天把一個去年沒做完的專案翻出來做時，發現maven無法正常匯入依賴。檢查了一遍專案配置，沒發現有什麼問題。而且依賴在本地倉庫存在。

隨後發現報錯：Failed to transfer file:*********. Return code is: 501 , ReasonPhrase:HTTPS Required. 這時候好像發現了什麼重點————我們需要將maven配置修改一下：

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

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

隨後發現可以正常匯入依賴了。

在stackoverflow上查了下，發現有人也遇到了這個問題：

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.

所以這個問題的根源就是maven中央倉庫現在只支援HTTPS協議，我們改一下就行。

&n