Wrong with (a)

Error place: The following is a pom.xml file, only part of the file currently affecting some external dependency newspaper red jar package to import and use its library methods!

pom.xml file

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
    </parent>
    <groupId>com.xuecheng</groupId>
    <artifactId>xc-framework-parent</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <java.version>1.8</java.version>
        <tomcat.version>8.5.28</tomcat.version>
        <spring-boot.version>2.0.1.RELEASE</spring-boot.version>
        <springframework.version>5.0.5.RELEASE</springframework.version>
        <mybatis-spring-boot.version>1.3.1</mybatis-spring-boot.version>
        <mybatis.version>3.4.5</mybatis.version>
        <druid.version>1.1.6</druid.version>
        <mysql-connector-java.version>5.1.45</mysql-connector-java.version>


        <commons-io.version>2.6</commons-io.version>
        <org.apache.commons.io.version>1.3.2</org.apache.commons.io.version>
        <commons-fileupload.version>1.3.3</commons-fileupload.version>
        <commons-codec.version>1.10</commons-codec.version>
        <commons-lang3.version>3.6</commons-lang3.version>
        <okhttp.version>3.9.1</okhttp.version>
        <feign-okhttp.version>8.18.0</feign-okhttp.version>
        <lombok.version>1.16.16</lombok.version>
        <springfox-swagger.version>2.7.0</springfox-swagger.version>
        <fastjson.version>1.2.30</fastjson.version>
        <fastdfs-client-java.version>1.27.0.0</fastdfs-client-java.version>
        <mysql-connector-java.version>5.1.40</mysql-connector-java.version>
        <elasticsearch.version>6.2.1</elasticsearch.version>
        <guava.version>24.0-jre</guava.version>
    </properties>
    <!--test-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Finchley.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql-connector-java.version}</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis-spring-boot.version}</version>
            </dependency>
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper-spring-boot-starter</artifactId>
                <version>1.2.4</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>

            <dependency>
                <groupId>com.squareup.okhttp3</groupId>
                <artifactId>okhttp</artifactId>
                <version>${okhttp.version}</version>
            </dependency>
            <dependency>
                <groupId>com.netflix.feign</groupId>
                <artifactId>feign-okhttp</artifactId>
                <version>${feign-okhttp.version}</version>
            </dependency>
            <dependency>
                <groupId>commons-io</groupId>
                <artifactId>commons-io</artifactId>
                <version>${commons-io.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.commons</groupId>
                <artifactId>commons-io</artifactId>
                <version>${org.apache.commons.io.version}</version>
            </dependency>
            <dependency>
                <groupId>commons-fileupload</groupId>
                <artifactId>commons-fileupload</artifactId>
                <version>${commons-fileupload.version}</version>
            </dependency>
            <dependency>
                <groupId>commons-codec</groupId>
                <artifactId>commons-codec</artifactId>
                <version>${commons-codec.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.commons</groupId>
                <artifactId>commons-lang3</artifactId>
                <version>${commons-lang3.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger2</artifactId>
                <version>${springfox-swagger.version}</version>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger-ui</artifactId>
                <version>${springfox-swagger.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>${fastjson.version}</version>
            </dependency>
            <dependency>
                <groupId>net.oschina.zcx7878</groupId>
                <artifactId>fastdfs-client-java</artifactId>
                <version>${fastdfs-client-java.version}</version>
            </dependency>

            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>elasticsearch-rest-high-level-client</artifactId>
                <version>${elasticsearch.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.elasticsearch/elasticsearch -->
            <dependency>
                <groupId>org.elasticsearch</groupId>
                <artifactId>elasticsearch</artifactId>
                <version>${elasticsearch.version}</version>
            </dependency>
            <dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>${guava.version}</version>
            </dependency>

        </dependencies>
    </dependencyManagement>
    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <!-- &lt;!&ndash; 资源文件拷贝插件 &ndash;&gt;
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-resources-plugin</artifactId>
                 <configuration>
                     <encoding>UTF-8</encoding>
                 </configuration>
             </plugin>-->
            <!-- java编译插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Specific Information: IDEA 15.0.6 + Spring Boot 2.0.1 - "mysql, pagehelper, druid not see some other dependencies maven automatically downloaded JAR package External Libraries

Self-judgment: Suspected maven did not go automatically import the missing part of the jar package - "Why can not import portion of the jar package? - "

Self solve 1: First suspected network outages - "the right side of the blue maven project be clean + install and reimport (useless)

Self solve 2: With tragic mood of the original External Libraries download Maven jar package backup - "and then find a've downloaded (with the) Libraries file all required jar package folder and replace the [original] Libraries - "but click maven of reimport, and find that it becomes original Libraries!

Self solve 3: delete all lib inside a jar + target file - "reimport--" Ibid results

Shock! Some written in dependency do not get inside the jar maven automatically downloads the package?

magical! The left maven obviously did not automatically import apache.commons.io, on the right did not actually being given?