Jackrabbit FirstHop示例java.lang.NoClassDefFoundError

Question

我正在尝试使用在Apache网站上提供的Jackrabbit FirstHops示例，但是在尝试运行时我遇到了以下错误。

S:\mvnapp\FirstHop2>java -cp target\FirstHop2-1.0-SNAPSHOT.jar org.shobhan.jr.Fi
rstHopSB
Exception in thread "main" java.lang.NoClassDefFoundError: javax/jcr/Credentials

    Caused by: java.lang.ClassNotFoundException: javax.jcr.Credentials
            at java.net.URLClassLoader$1.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    Could not find the main class: org.shobhan.jr.FirstHopSB.  Program will exit.

下面是Pom.xml文件，我添加了apache站点上提供的依赖项。

<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>org.shobhan.jr</groupId>
  <artifactId>FirstHop2</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>FirstHop2</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

    <dependencies> 
    <!-- The JCR API --> 
        <dependency> 
            <groupId>javax.jcr</groupId> 
            <artifactId>jcr</artifactId> 
            <version>2.0</version> 
        </dependency> 
        <!-- Jackrabbit content repository --> 
        <dependency> 
            <groupId>org.apache.jackrabbit</groupId> 
            <artifactId>jackrabbit-core</artifactId> 
            <version>2.9.0</version> 
        </dependency> 
        <!-- Use Log4J for logging --> 
        <dependency> 
            <groupId>org.slf4j</groupId> 
            <artifactId>slf4j-log4j12</artifactId> 
            <version>1.7.5</version> 
        </dependency> 
    </dependencies> 
</project>

我的环境低于值。

CLASSPATH = C：\ Program Files \ Java \ jdk1.6.0_17 \ bin; S：\ JR \ jackrabbit-standalone-2.8.0.jar JAVA_HOME = C：\ Program Files \ Java \ jdk1.6.0_17

M2_HOME = S：\ maven \ apache-maven-3.2.5 PATH =％SystemRoot％\ system32;％SystemRoot％;％SystemRoot％\ System32 \ Wbem;％SYSTEMROOT％\ System32 \ WindowsPowerShell \ v1.0 \; S：\ maven \ apache-maven-3.2.5 \ bin; C：\ Program Files \ Java \ jdk1.6.0_17 \ bin

Answer 1

此错误，“NoClassDefFound”在编译时存在库时发生，但不在运行时类路径中。它几乎总是意味着运行时类路径缺少JAR。如果要对其进行硬编码，则需要在类路径中包含jcr jar。

更好的方法是使用maven exec：java插件。更新：Here is a gist with a working pom.xml

尝试在“depdendencies”之后将其添加到pom.xml中。

  <build><plugins>
  <plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.2.1</version>
    <executions>
      <execution>
        <goals>
          <goal>exec</goal>
        </goals>
      </execution>
    </executions>
    <configuration>
      <executable>java</executable>
      <includeProjectDependencies>true</includeProjectDependencies>
      <includePluginDependencies>false</includePluginDependencies>
      <classpathScope>compile</classpathScope>
      <mainClass>com.whatever.MyMainClassy</mainClass>
    </configuration>
  </plugin>
  </plugins></build>

然后您可以使用

运行

mvn exec:java

它将使用与编译时相同的类路径。

在本地测试，您的输出应如下所示：

mvn exec:java
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building FirstHop2 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ FirstHop2 >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ FirstHop2 <<<
[INFO]
[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ FirstHop2 ---
Logged in as anonymous to a Jackrabbit repository.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 5.420s
[INFO] Finished at: Mon Jan 12 15:27:03 EST 2015
[INFO] Final Memory: 17M/231M
[INFO] ------------------------------------------------------------------------

Answer 2

通过使用SE应用程序，这个问题在我的案例中得到了解决。