Intellij 导入 eclipse工程，Cannot resolve symbol *问题

问题一：
导入eclipse的springboot工程，要选择pom.xml文件。如果直接选择整个工程的文件夹，将会出错，提示Cannot resolve symbol *的问题。
两中导入方法，主要差别如下图：

右边是选择pom.xml导入的，idea自动导入了maven的包在libraries，而且生成了和工程对应的iml文件：

"1.0" encoding="UTF-8"?>
<module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
  "FacetManager">
    type="Spring" name="Spring">
      
    
    type="web" name="Web">
      
        
      
    
  
  "NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_8">
    
"file://$MODULE_DIR$/target/classes" />
    "file://$MODULE_DIR$/target/test-classes" />
    "file://$MODULE_DIR$">
      "file://$MODULE_DIR$/src/main/java" isTestSource="false" />
      "file://$MODULE_DIR$/src/main/resources" type="java-resource" />
      "file://$MODULE_DIR$/target" />
    
    type="inheritedJdk" />
    type="sourceFolder" forTests="false" />
    type="library" name="Maven: org.mybatis.spring.boot:mybatis-spring-boot-starter:1.3.1" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-autoconfigure:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-logging:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: ch.qos.logback:logback-classic:1.1.11" level="project" />
    type="library" name="Maven: ch.qos.logback:logback-core:1.1.11" level="project" />
    type="library" name="Maven: org.slf4j:slf4j-api:1.7.25" level="project" />
    type="library" name="Maven: org.slf4j:jcl-over-slf4j:1.7.25" level="project" />
    type="library" name="Maven: org.slf4j:jul-to-slf4j:1.7.25" level="project" />
    type="library" name="Maven: org.slf4j:log4j-over-slf4j:1.7.25" level="project" />
    type="library" name="Maven: org.springframework:spring-core:4.3.13.RELEASE" level="project" />
    type="library" scope="RUNTIME" name="Maven: org.yaml:snakeyaml:1.17" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-jdbc:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.apache.tomcat:tomcat-jdbc:8.5.23" level="project" />
    type="library" name="Maven: org.apache.tomcat:tomcat-juli:8.5.23" level="project" />
    type="library" name="Maven: org.springframework:spring-jdbc:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-tx:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.mybatis.spring.boot:mybatis-spring-boot-autoconfigure:1.3.1" level="project" />
    type="library" name="Maven: org.mybatis:mybatis:3.4.5" level="project" />
    type="library" name="Maven: org.mybatis:mybatis-spring:1.3.1" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-security:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-aop:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-beans:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.security:spring-security-config:4.2.3.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.security:spring-security-core:4.2.3.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-context:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.security:spring-security-web:4.2.3.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-expression:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-web:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-tomcat:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-core:8.5.23" level="project" />
    type="library" name="Maven: org.apache.tomcat:tomcat-annotations-api:8.5.23" level="project" />
    type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-el:8.5.23" level="project" />
    type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-websocket:8.5.23" level="project" />
    type="library" name="Maven: org.hibernate:hibernate-validator:5.3.6.Final" level="project" />
    type="library" name="Maven: javax.validation:validation-api:1.1.0.Final" level="project" />
    type="library" name="Maven: org.jboss.logging:jboss-logging:3.3.1.Final" level="project" />
    type="library" name="Maven: com.fasterxml:classmate:1.3.4" level="project" />
    type="library" name="Maven: com.fasterxml.jackson.core:jackson-databind:2.8.10" level="project" />
    type="library" name="Maven: com.fasterxml.jackson.core:jackson-annotations:2.8.0" level="project" />
    type="library" name="Maven: com.fasterxml.jackson.core:jackson-core:2.8.10" level="project" />
    type="library" name="Maven: org.springframework:spring-web:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-webmvc:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: com.alibaba:druid:1.0.29" level="project" />
    type="module-library">
      "Maven: com.alibaba:jconsole:1.8.0">
        
          "jar://C:/Program Files/Java/jdk1.8.0_111/lib/jconsole.jar!/" />
        
        
        
      
    
    type="module-library">
      "Maven: com.alibaba:tools:1.8.0">
        
          "jar://C:/Program Files/Java/jdk1.8.0_111/lib/tools.jar!/" />
        
        
        
      
    
    type="library" name="Maven: mysql:mysql-connector-java:5.1.44" level="project" />
    type="library" name="Maven: org.apache.poi:poi:3.17" level="project" />
    type="library" name="Maven: commons-codec:commons-codec:1.10" level="project" />
    type="library" name="Maven: org.apache.commons:commons-collections4:4.1" level="project" />
    type="library" name="Maven: com.sun.mail:javax.mail:1.5.6" level="project" />
    type="library" name="Maven: javax.activation:activation:1.1" level="project" />
    type="library" name="Maven: org.freemarker:freemarker:2.3.27-incubating" level="project" />
    type="library" name="Maven: org.springframework.boot:spring-boot-starter-websocket:1.5.9.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-messaging:4.3.13.RELEASE" level="project" />
    type="library" name="Maven: org.springframework:spring-websocket:4.3.13.RELEASE" level="project" />
  
module>

问题二
现象：
Intellij新建的springboot工程，该工程能运行，但是界面显示Cannot resolve symbol *，某些类库和注解都变红，如下图：

原因和解决方法：
Intellij的maven配置有问题，原配置如下：

这个是Intellij自动生成的，改成你maven实际的配置，如下：

然后clean maven并重新加载依赖，解决问题