搭建springboot，报错：Failed to configure a DataSource: 'url' attribute is not specified and no embedd。

第一次打开项目报白页，第二次突然就启动不了了，而且控制台报错如下：

Description:

Failed to configure a DataSource: ‘url’ attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class

Action:

Consider the following:
If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

找了很久的原因，发现是pom.xml的project总是报红线。先clean一下，然后install，发现有个jar包有问题

然后打开本地maven仓库，把其他版本的jar包删掉，把2.1.9版本里面的文件都删掉，重新download一下，发现果然有问题，只下载了一个xxxxxpom.lastUpdated.在网上找一下jar包，把jar包更换一下再次打开项目，就不报错了，同时也不报白页了。