java - Maven - 对于 Artifact ，版本不能为空

Question

问题:我正在使用maven，突然出现一些错误:

For artifact {org.springframework.boot:spring-boot-starter-data-jpa:null:jar}: The version cannot be empty. (org.apache.maven.plugins:maven-resources-plugin:2.6:resources:default-resources:process-resources)

org.apache.maven.artifact.InvalidArtifactRTException: For artifact {org.springframework.boot:spring-boot-starter-data-jpa:null:jar}: The version cannot be empty.
    at org.apache.maven.artifact.DefaultArtifact.validateIdentity(DefaultArtifact.java:148)
    at org.apache.maven.artifact.DefaultArtifact.<init>(DefaultArtifact.java:123)
    at org.apache.maven.artifact.factory.DefaultArtifactFactory.createArtifact(DefaultArtifactFactory.java:157)
    at org.apache.maven.artifact.factory.DefaultArtifactFactory.createDependencyArtifact(DefaultArtifactFactory.java:57)
    at org.apache.maven.project.artifact.MavenMetadataSource.createDependencyArtifact(MavenMetadataSource.java:328)
    at org.apache.maven.project.artifact.MavenMetadataSource.createArtifacts(MavenMetadataSource.java:503)
    at org.apache.maven.lifecycle.internal.DefaultProjectArtifactFactory.createArtifacts(DefaultProjectArtifactFactory.java:50)
    at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.resolveProjectDependencies(LifecycleDependencyResolver.java:119)
    at org.apache.maven.lifecycle.internal.MojoExecutor.ensureDependenciesAreResolved(MojoExecutor.java:245)
    at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:330)
    at org.eclipse.m2e.core.internal.embedder.MavenImpl$11.call(MavenImpl.java:1362)
    at org.eclipse.m2e.core.internal.embedder.MavenImpl$11.call(MavenImpl.java:1)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:176)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
    at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:1360)
    at org.eclipse.m2e.core.project.configurator.MojoExecutionBuildParticipant.build(MojoExecutionBuildParticipant.java:52)
    at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:137)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:172)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1$1.call(MavenBuilder.java:115)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:176)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1.call(MavenBuilder.java:105)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:176)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:151)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:99)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:86)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:200)
    at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:735)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:246)
    at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:301)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:304)
    at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:360)
    at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:383)
    at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:144)
    at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:235)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

所以我添加了 Artifact 版本<version>1.3.5.RELEASE</version>到 spring-boot-starter-data-jpa。不幸的是我仍然遇到同样的问题。我什至清理了 Maven 的缓存。 maven -> update项目没有帮助 和 project -> clean都没有帮助

问题:我还做错了什么？

pom.xml

<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>SpringDataDemo</groupId>
    <artifactId>SpringDataDemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <warSourceDirectory>WebContent</warSourceDirectory>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>https://repo.spring.io/libs-release</url>
        </repository>
        <repository>
            <id>org.jboss.repository.releases</id>
            <name>JBoss Maven Release Repository</name>
            <url>https://repository.jboss.org/nexus/content/repositories/releases</url>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>https://repo.spring.io/libs-release</url>
        </pluginRepository>
    </pluginRepositories>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <version>1.3.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.192</version>
        </dependency>

    </dependencies>


</project>

如果确实是版本号问题，Eclipse 会将奇怪的行标记为红色:

Answer 1

需要继承Spring Boot的父POM:

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.5.RELEASE</version>
</parent>

这个父 POM 为您可能在项目中使用的 Artifact 声明了许多依赖版本，这样您就不需要自己指定它。

来自docs :

Each release of Spring Boot provides a curated list of dependencies it supports. In practice, you do not need to provide a version for any of these dependencies in your build configuration as Spring Boot is managing that for you. When you upgrade Spring Boot itself, these dependencies will be upgraded as well in a consistent way.

另请参阅:

• Getting Started - Building an Application with Spring Boot