Maven Eclipse：添加 maven jar 项目作为对战争项目的引用答案

【问题标题】：Maven Eclipse: Add maven jar project as a reference to an war projectMaven Eclipse：添加 maven jar 项目作为对战争项目的引用
【发布时间】：2014-07-04 07:59:56
【问题描述】：

我尝试将我的自定义 jar maven 项目作为依赖项添加到 war 项目中，但如果我尝试在 Eclipse 中的 Apache 7 服务器上运行它，它仍然会抛出 NoClassDefFoundError。

我的 .war 项目的 pom 如下所示：

<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>de.dbbase.apps</groupId>
    <artifactId>jwt</artifactId>
    <version>0.0.2</version>
    <packaging>war</packaging>

<!--    <parent> -->
<!--        <groupId>de.dbbase.core</groupId> -->
<!--        <artifactId>jwtpom</artifactId> -->
<!--        <version>0.0.1</version> -->
<!--    </parent> -->

    <properties>
        <org.springframework.version>4.0.2.RELEASE</org.springframework.version>
        <ch.qos.logback.version>1.1.1</ch.qos.logback.version>
    </properties>

    <dependencies>
        <!-- ####################################################################################################### -->
        <!-- Core abhängigkeiten für ein Web-Project  -->

        <dependency> <!-- For HttpSessionListener -->
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-servlet-api</artifactId>
            <version>8.0.5</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>

        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- To use @ManagedBean, @SessionScoped, ... -->
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

         <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${org.springframework.version}</version>
         </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${org.springframework.version}</version>
            <exclusions>
<!--            Wenn logback verwendet wird -->
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
             </exclusions>
        </dependency>

        <!-- ####################################################################################################### -->
        <!-- Logging -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.6</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${ch.qos.logback.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${ch.qos.logback.version}</version>
        </dependency>


        <!-- ####################################################################################################### -->
        <!-- MongoDB -->
        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongo-java-driver</artifactId>
            <version>2.11.4</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
            <version>1.4.0.RELEASE</version>
        </dependency>

        <!-- ####################################################################################################### -->
        <!-- Sonstiges -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.12.4</version>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.3</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.13</version>
        </dependency>

        <dependency>
            <groupId>de.dbbase.libs</groupId>
            <artifactId>dbbase-auth</artifactId>
            <version>0.0.1</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.0</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

和我的 maven jar 项目的 pom：

<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>de.dbbase.libs</groupId>
    <artifactId>dbbase-auth</artifactId>
    <version>0.0.1</version>

    <properties>
        <org.springframework.version>4.0.2.RELEASE</org.springframework.version>
        <ch.qos.logback.version>1.1.1</ch.qos.logback.version>
    </properties>

    <dependencies>
        <!-- ####################################################################################################### -->
        <!-- Core abhängigkeiten für ein Web-Project -->
        <dependency> <!-- For HttpSessionListener -->
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-servlet-api</artifactId>
            <version>8.0.5</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>

        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- To use @ManagedBean, @SessionScoped, ... -->
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${org.springframework.version}</version>
            <exclusions>
                <!-- Wenn logback verwendet wird -->
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
             </exclusions>
        </dependency>

        <!-- ####################################################################################################### -->
        <!-- Logging -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.6</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${ch.qos.logback.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${ch.qos.logback.version}</version>
        </dependency>


        <!-- ####################################################################################################### -->
        <!-- MongoDB -->
        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongo-java-driver</artifactId>
            <version>2.11.4</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
            <version>1.4.0.RELEASE</version>
        </dependency>

        <!-- ####################################################################################################### -->
        <!-- Sonstiges -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.12.4</version>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.3</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.0</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

如果我将我的战争项目导出为战争，那么我的 dbbase-auth 项目的 jar 将位于 libs 文件夹中。但是每次我在 Tomcat 7 服务器上的 Eclipse 中运行 war 项目时，我在 war 项目中使用的 dbbase-auth jar 项目中的每个类都会出现java.lang.NoClassDefFoundError。

编辑：

我的 Stacktrace 如下所示：

@Pracede here is the stacktrace:java.lang.NoClassDefFoundError: Lde/dbbase/libs/auth/user/service/UserDBService;
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Unknown Source)
    at java.lang.Class.getDeclaredFields(Unknown Source)
    at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.findResourceMetadata(CommonAnnotationBeanPostProcessor.java:327)
    at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(CommonAnnotationBeanPostProcessor.java:283)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:908)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:512)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: de.dbbase.libs.auth.user.service.UserDBService
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1718)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1569)
    ... 27 more

【问题讨论】：

这从未发生在我身上。你能显式地声明依赖范围为compile吗？此外，将 jar 显式添加到您的 jar pom
能否请您发布 stackstrace 错误？
所以看起来 Maven 正确处理了 dbbase 工件，但 Eclipse 没有？也许你的 Eclipse 项目设置是罪魁祸首。我记得 Eclipse maven 插件对 maven 项目的工作区分辨率相当挑剔 - 但后来我切换到 IntelliJ :-)
@maress 显式添加包装和范围不会改变任何事情，因为它们是默认值。
检查@Anders 的答案，这就是问题所在

标签： java eclipse maven tomcat7

【解决方案1】：

我认为这可能是问题所在：

    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-api</artifactId>
        <version>7.0</version>
        <scope>provided</scope>
    </dependency>

AFAIK Tomcat 不提供此 API 的实现。因此，您的应用会编译，但会在运行时抛出 NoClassDefFoundError。

使用提供此实现的服务器（即TomEE）

【讨论】：

案例 1： 我只用一个项目对其进行了测试（没有将我的 dbbase-auth-Project 设置为依赖项），我对 javaee-api 没有任何问题。 案例 2： 如果我从我的战争和我的 jar 项目中删除 javaee-api 依赖项，我会遇到同样的问题（不会有任何改变）。
只有在尝试使用 API 时才会出现此异常。
这不是真的，我已经删除了 api 但是会再次抛出异常。