SpringBoot 项目不加载 application.properties 配置文件

起因：新安装的idea第一次运行springboot项目报url错误(Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.)，配置文件application.properties中的代码都是灰色的，而且配置文件的图标也不是绿叶子

推测原因是未扫描(没有找到)到这个配置文件

一顿百度之后，借用该帖子(https://www.cnblogs.com/toutou/archive/2019/08/31/embedded-datasource.html)的第四种方法

yml或者properties文件没有被扫描到,需要在pom文件中<build></build>添加如下.来保证文件都能正常被扫描到并且加载成功.
<!-- 如果不添加此节点mybatis的mapper.xml文件都会被漏掉。 -->
<resources>
    <resource>
        <directory>src/main/java</directory>
        <includes>
            <include>**/*.yml</include>
            <include>**/*.properties</include>
            <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
    </resource>
    <resource>
        <directory>src/main/resources</directory>
        <includes>
            <include>**/*.yml</include>
            <include>**/*.properties</include>
            <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
    </resource>
</resources>

加了之后读取到配置文件了但是访问html页面404
去掉这段代码之后再次运行既可以读取到配置文件又可以访问html页面

可能是idea反应过来了

再次创建项目就不会出现这种读取不到配置文件的现象

如果要用到MyBatis可以在pom文件中<build></build>添加如下

<build>
      <resources>
          <resource>
              <directory>src/main/java</directory>
              <includes>
                  <include>**/*.xml</include>
              </includes>
          </resource>
      </resources>
      <plugins>
          <plugin>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-maven-plugin</artifactId>
          </plugin>
      </plugins>
  </build>