我试图按照“使用GlassFish 3开始Java EE 6平台”一书的第2章中的示例。我在Windows中使用来自cmd的EclipseLink，Derby和Maven。我真的无法理解这一点，并会感激一些帮助！
我的Main.java类中的这一行EntityManagerFactory emf = Persistence.createEntityManagerFactory("chapter02PU");生成以下错误：
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Chapter 02 - JPA 0.1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.5:resources (default-resources) @ chapter02 ---
[debug] execute contextualize
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ chapter02 ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ chapter02 >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ chapter02 <<<
[INFO]
[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ chapter02 ---
[WARNING]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:297)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NoClassDefFoundError: javax/persistence/Persistence
at org.beginningee6.book.chapter02.Main.main(Main.java:22)
... 6 more
Caused by: java.lang.ClassNotFoundException: javax.persistence.Persistence
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 7 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 8.390s
[INFO] Finished at: Tue Mar 19 23:13:36 CET 2013
[INFO] Final Memory: 8M/105M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project chapter02: An exception occured while executing the Java class. null: InvocationTargetException: javax/persistence/Persistence: javax.persistence.Persistence -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project chapter02: An exception occured while executing the Java class. null
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:217)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.MojoExecutionException: An exception occured while executing the Java class. null
at org.codehaus.mojo.exec.ExecJavaMojo.execute(ExecJavaMojo.java:352)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
... 19 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:297)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NoClassDefFoundError: javax/persistence/Persistence
at org.beginningee6.book.chapter02.Main.main(Main.java:22)
... 6 more
Caused by: java.lang.ClassNotFoundException: javax.persistence.Persistence
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 7 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
这是我的Main.java类：
package org.beginningee6.book.chapter02;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
public class Main {
public static void main(String[] args) {
Book book = new Book();
book.setTitle("The Hitchhicker's Guide to the Galaxy");
book.setPrice(12.5F);
book.setDescription("SCience fiction comedy book");
book.setIsbn("1-84023-742-2");
book.setNbOfPage(354);
book.setIllustrations(false);
// Get en entity manager and a transaction
EntityManagerFactory emf = Persistence.createEntityManagerFactory("chapter02PU");
//EntityManager em = emf.createEntityManager();
//Persist the book to the database
/*EntityTransaction tx = em.getTransaction();
tx.begin();
em.persist(book);
tx.commit();
em.close();
emf.close();*/
}
}
这是我的Book.java类：
package org.beginningee6.book.chapter02;
import javax.persistence.*;
@Entity
@NamedQuery(name = "findAllBooks", query = "SELECT b FROM Book b")
public class Book {
@Id
@GeneratedValue
private Long id;
@Column(nullable = false)
private String title;
private Float price;
@Column(length = 2000)
private String description;
private String isbn;
private Integer nbOfPage;
private Boolean illustrations;
public Book() {
}
//Plus getters and setter.
这是我的persistence.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="chapter02PU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>org.beginningee6.book.chapter02.Book</class>
<properties>
<property name="eclipselink.target-database" value="DERBY"/>
<property name="eclipselink.ddl-generation" value="create-tables"/>
<property name="eclipselink.logging.level" value="INFO"/>
<property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.EmbeddedDriver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:derby:memory:chapter02DB;create=true"/>
<!-- <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/chapter02DB;create=true"/> -->
<property name="javax.persistence.jdbc.user" value="APP"/>
<property name="javax.persistence.jdbc.password" value="APP"/>
</properties>
</persistence-unit>
</persistence>
这是我的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>org.beginningee6.book</groupId>
<artifactId>chapter02</artifactId>
<version>0.1</version>
<name>Chapter 02 - JPA</name>
<dependencies>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>javax.persistence</artifactId>
<version>2.0.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.4.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derbyclient</artifactId>
<version>10.8.2.2</version>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.8.2.2</version>
</dependency>
</dependencies>
</project>
这是我在Eclipse中的文件结构：
JavaEEAPress\src\main\java\org\beginningee6\book\chapter02\Book.java
JavaEEAPress\src\main\java\org\beginningee6\book\chapter02\Main.java
JavaEEAPress\src\main\resources\META-INF\persistence.xml
JavaEEAPress\pom.xml
答案 0 :(得分：3)
您在持久性库中指定了provided范围。
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>javax.persistence</artifactId>
<version>2.0.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.4.0</version>
<scope>provided</scope>
</dependency>
这基本上告诉Maven'为了编译的目的，使用这些库，但不要将它们包含在我的最终工件中，因为它们最终将通过其他方式提供'。我确定您所关注的教程以这种方式定义它们，因为您希望将代码部署到要执行的应用程序服务器。在这种情况下，确实提供了这些库。
但是，在这种情况下，您运行的是独立的Java应用程序，并且需要明确地包含这些库。最简单的解决方法是将org.eclipse.persistence:javax.persistence和org.eclipse.persistence:eclipselink的范围从provided更改为runtime。但前提是您从未打算将示例部署到应用程序服务器。更好的选择是定义运行独立代码的配置文件：
<profiles>
<profile>
<id>standalone</id>
<dependencies>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>javax.persistence</artifactId>
<version>2.0.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.4.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
</profile>
</profiles>
通过使用配置文件选项执行Maven将激活：
mvn clean install -Pstandalone
答案 1 :(得分：0)
我不确定问题是什么，但是当我根据此链接更新代码时，我得到了它。 https://github.com/agoncal/agoncal-book-javaee6
上面链接中的代码似乎比此链接中的代码更新，我之前一直在查看。 http://kenai.com/projects/beginningee6/
答案 2 :(得分：0)
我也遇到了你的问题，但我解决了。我改变了我的罐子，问题就消失了，也许这些罐子彼此不兼容。