如何在运行"mvn clean install"时修复警告消息

Question

我正在使用 jdk 8 和 maven 版本 3.3.9 创建具有最新版本 1.5.6.RELEASE 的 spring 启动应用程序。我在运行mvn clean install时收到以下警告消息

[DEBUG] Looking up lifecyle mappings for packaging pom from ClassRealm[plexus.core, parent: null]
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for com.XXXX:foo:jar:1.0.0
[WARNING] 'parent.relativePath' of POM com.XXX:foo:1.0.0 (/home/user/parent/foo/pom.xml) points at com.XXX:parent instead of org.springframework.boot:spring-boot-starter-parent, please verify your project structure @ line 12, column 13
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for com.XXX:bar:jar:1.0.0
[WARNING] 'parent.relativePath' of POM com.XXX:bar:1.0.0 (/home/user/parent/bar/pom.xml) points at com.XXX:parent instead of org.springframework.boot:spring-boot-starter-parent, please verify your project structure @ line 12, column 13
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING] 
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:

我的项目是一个多模块构建。目录结构为：

xxx-project
|-- pom.xml
|-- foo
|   |-- pom.xml
|-- bar
|   |-- pom.xml

我的foo/pom.xml是：

<?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.xxx</groupId>
<artifactId>foo</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<name>foo</name>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<start-class>com.xxx.foo.App</start-class>
<java.version>1.8</java.version>
<lombok.version>1.16.18</lombok.version>
<log4jdbc.log4j2.version>1.16</log4jdbc.log4j2.version>
<rest.assured.version>3.0.3</rest.assured.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombok.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.bgee.log4jdbc-log4j2</groupId>
<artifactId>log4jdbc-log4j2-jdbc4.1</artifactId>
<version>${log4jdbc.log4j2.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>rest-assured</artifactId>
<version>${rest.assured.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
<version>${spring-loaded.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>

上面的pom.xml是使用来自github的maven原型spring-boot-blank项目生成的。

父pom.xml是：

<?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.XXX</groupId>
<artifactId>parent</artifactId>
<version>1.0.0</version>
<packaging>pom</packaging>
<name>parent</name>
<modules>
<module>foo</module>
<module>bar</module>
</modules>
</project>

如何在编译源代码时解决此警告消息？

请提供您的意见。

Answer 1

出现此问题的原因是 Maven 默认假定父 pom 位于包含模块 pom 的父文件夹中。但是，在您的项目中，情况似乎并非如此：您的父 pom 是org.springframework.boot：spring-boot-starter-parent：1.5.6.RELEASE，而父文件夹中的 pomcom.xxx：parent：1.0.0仅用作模块的聚合器。

要解决此问题，您需要在模块 poms 中的父声明中取消设置相对路径，如下所示：

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
<relativePath/>
</parent>