在IDEA中，明明下载好了依赖包，为什么Maven父工程不能正确显示依赖项，子工程可以显示？怎么解决？

Question

在IDEA中，明明下载好了依赖包，为什么Maven父工程不能正确显示依赖项，子工程可以显示？怎么解决？

子工程可以正确显示依赖项

父工程显示不了依赖项，啥也没有

父工程的pom.xml文件：

<?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>

    <groupId>com.atguigu.cloud</groupId>
    <artifactId>cloud2025</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>
    <modules>
        <module>untitled</module>
    </modules>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <hutool.version>5.8.22</hutool.version>
        <lombok.version>1.18.26</lombok.version>
        <druid.version>1.1.20</druid.version>
        <mybatis.springboot.version>3.0.2</mybatis.springboot.version>
        <mysql.version>8.0.11</mysql.version>
        <swagger3.version>2.2.0</swagger3.version>
        <mapper.version>4.2.3</mapper.version>
        <fastjson2.version>2.0.40</fastjson2.version>
        <persistence-api.version>1.0.2</persistence-api.version>
        <spring.boot.test.version>3.1.5</spring.boot.test.version>
        <spring.boot.version>3.2.0</spring.boot.version>
        <spring.cloud.version>2023.0.0</spring.cloud.version>
        <spring.cloud.alibaba.version>2022.0.0.0-RC2</spring.cloud.alibaba.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!--springboot 3.2.0-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>${spring.boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--springcloud 2023.0.0-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring.cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--springcloud alibaba 2022.0.0.0-RC2-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring.cloud.alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--SpringBoot集成mybatis-->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis.springboot.version}</version>
            </dependency>
            <!--Mysql数据库驱动8 -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            <!--SpringBoot集成druid连接池-->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>${druid.version}</version>
            </dependency>
            <!--通用Mapper4之tk.mybatis-->
            <dependency>
                <groupId>tk.mybatis</groupId>
                <artifactId>mapper</artifactId>
                <version>${mapper.version}</version>
            </dependency>
            <!--persistence-->
            <dependency>
                <groupId>javax.persistence</groupId>
                <artifactId>persistence-api</artifactId>
                <version>${persistence-api.version}</version>
            </dependency>
            <!-- fastjson2 -->
            <dependency>
                <groupId>com.alibaba.fastjson2</groupId>
                <artifactId>fastjson2</artifactId>
                <version>${fastjson2.version}</version>
            </dependency>
            <!-- swagger3 调用方式 http://你的主机IP地址:5555/swagger-ui/index.html -->
            <dependency>
                <groupId>org.springdoc</groupId>
                <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
                <version>${swagger3.version}</version>
            </dependency>
            <!--hutool-->
            <dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
                <version>${hutool.version}</version>
            </dependency>
            <!--lombok-->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
                <optional>true</optional>
            </dependency>
            <!-- spring-boot-starter-test -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <version>${spring.boot.test.version}</version>
                <scope>test</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

子工程的pom.xml文件

<?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>com.atguigu.cloud</groupId>
        <artifactId>cloud2024</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>mybatis_generator2024</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--Mybatis 通用mapper tk单独使用，自己独有+自带版本号-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.13</version>
        </dependency>
        <!-- Mybatis Generator 自己独有+自带版本号-->
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.4.2</version>
        </dependency>
        <!--通用Mapper-->
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper</artifactId>
        </dependency>
        <!--mysql8.0-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--persistence-->
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>persistence-api</artifactId>
        </dependency>
        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>${basedir}/src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>${basedir}/src/main/resources</directory>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.4.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.33</version>
                    </dependency>
                    <dependency>
                        <groupId>tk.mybatis</groupId>
                        <artifactId>mapper</artifactId>
                        <version>4.2.3</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>

</project>

Answer 1

让阿豪来帮你解答，本回答参考chatgpt3.5编写提供，如果还有疑问可以评论或留言

问题分析： 从截图中可以看出，子工程可以正确显示依赖项，而父工程却不能正确显示依赖项。这种情况可能是由于父工程没有正确定义依赖关系引起的。 解决方法：

1. 确认父工程中是否正确定义了依赖关系。 查看父工程的pom文件，确认是否有正确定义依赖关系。如果没有，请在父工程的pom文件中添加正确的依赖关系。
2. 重新导入依赖项 在Maven中，右键单击项目，选择Maven->Reimport重新导入依赖项，然后重新构建项目。 以上两种方法无法解决问题的情况下，可以通过清理Maven本地仓库来解决问题：
3. 清理Maven本地仓库 在Maven本地仓库中，可能存在一些依赖项已经过期、版本不一致，或其他错误的依赖项。这种情况下，可以尝试清理Maven本地仓库，然后重新导入依赖项。 具体操作步骤如下： 1) 停止IDEA，关闭所有相关程序。 2) 打开命令行，输入以下命令清理本地仓库： Windows: del /s /q "C:\Users{user_name}.m2\repository*" rd /s /q "C:\Users{user_name}.m2\repository" Linux/Mac OS: rm -rf ~/.m2/repository/* 3) 重新启动IDEA，导入依赖项。 示例代码： 父工程的pom.xml文件示例代码：

<?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>
   <groupId>com.example</groupId>
   <artifactId>parent</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>pom</packaging>
   <modules>
      <module>child1</module>
      <module>child2</module>
   </modules>
   <dependencies>
      <!-- 父工程的依赖项 -->
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
         <version>2.5.3</version>
      </dependency>
   </dependencies>
   <dependencyManagement>
      <dependencies>
         <!-- 统一管理依赖版本 -->
         <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.5.3</version>
            <type>pom</type>
            <scope>import</scope>
         </dependency>
      </dependencies>
   </dependencyManagement>
</project>

子工程的pom.xml文件示例代码：

<?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>
   <groupId>com.example</groupId>
   <artifactId>child1</artifactId>
   <version>1.0-SNAPSHOT</version>
   <dependencies>
      <!-- 子工程的依赖项 -->
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

注意事项： 清理Maven本地仓库会删除所有本地仓库中的依赖项。在执行该操作之前，请备份您的依赖项，以免您需要重新下载这些依赖项。