问题
Im trying to follow the example in chapter 2 of the book Beginning Java EE 6 Platform with GlassFish 3. I am using EclipseLink, Derby and Maven from cmd in Windows. I really can't figure this out and would be grateful for some help!
This line EntityManagerFactory emf = Persistence.createEntityManagerFactory("chapter02PU"); in my Main.java class generates the following error:
[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
This is my Main.java class:
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();*/
}
}
This is my Book.java class:
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.
This is my persistence.xml file:
<?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>
This i my pom.xml file:
<?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>
And this is my file structure in Eclipse:
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
回答1:
You specified a provided scope on your persistence libraries.
<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>
That basically tells Maven that 'for purposes of compiling, use these libraries, but don't include them in my final artifact because they will eventually be provided by some other means'. I'm sure the tutorial you are following defined them this way because it is expected that you will be deploying your code to an application server to be executed. In such a scenario, those libraries are indeed provided.
But, in this case, you are running a standalone Java application, and you need to include those libraries explicitly. The simplest fix would be to change the scope, for org.eclipse.persistence:javax.persistence and org.eclipse.persistence:eclipselink from provided to runtime. But only if you never intend to deploy your examples to an application server. A better option would be to define a profile for running standalone code:
<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>
Which would be activated by executing Maven with a profile option:
mvn clean install -Pstandalone
回答2:
I'm not sure what the problem was but I got it to work when I updated the code according to this link. https://github.com/agoncal/agoncal-book-javaee6
The code in the link above seems to be more update-to-date than the code in this link, which I had been looking at before. http://kenai.com/projects/beginningee6/
回答3:
I also run to your problem,but I solve it. I change my jars the problem is gone away,maybe the jars are not compatible with each other.
来源：https://stackoverflow.com/questions/15511991/invocationtargetexception-javax-persistence-persistence