springboot启动忽然报错Could not resolve placeholder 'spring.datasource.driver-class-name'

以前好好的项目，今天启动忽然报错Could not resolve placeholder 'spring.datasource.driver-class-name'java 按照网友的方法，添加了spring @PropertySource(value = "classpath:application.properties", ignoreResourceNotFound = true) ，结果

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