我使用 Eclipse Helios、m2eclipse Maven 插件和 Glassfish 插件。我编辑了“pom.xml”文件，以便获得 DerbyClient 和 JPA Persistence 类。
<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>com.apress.javaee6</groupId>
<artifactId>chapter02</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>chapter02</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derbyclient</artifactId>
<version>10.6.1.0</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>javax.persistence</artifactId>
<version>2.0.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.0.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>2.4.3</version>
<type>maven-plugin</type>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>EclipseLink Repo</id>
<url>http://www.eclipse.org/downloads/download.php?r=1&nf=1&file=/rt/eclipselink/maven.repo</url>
</repository>
</repositories>
</project>
然后，我创建了“src/main/resrouce”目录并放置了一个“persistence.xml”文件，其中包含：
<xml version="1.0" encoding="UTF-8">
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
<persistence-unit name="chapter02PU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>com.apress.javaee6.chapter02.Book</class>
<properties>
<property name="eclipselink.target-datababase" value="DERBY"/>
<property name="eclipselink.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
<property name="eclipselink.jdbc.url" value="jdbc:derby://localhost:1527/chapter02DB;create=true"/>
<property name="eclipselink.jdbc.user" value="APP"/>
<property name="eclipselink.jdbc.password" value="APP"/>
<property name="eclipselink.jdbc.ddl-generation" value="create-tables"/>
<property name="eclipselink.jdbc.logging-level" value="INFO"/>
</properties>
</persistence-unit>
</persistence>
</xml>
当然，德比服务器运行完美。
我创建了以下书类：
package com.apress.javaee6.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 = 1000)
private String description;
private String isbn;
private Integer nbOfPage;
private Boolean illustrations;
public Book() {
super();
}
public Book(Long id, String title, float price, String description,
String isbn, Integer nbOfPage, Boolean illustrations) {
super();
this.id = id;
this.title = title;
this.price = price;
this.description = description;
this.isbn = isbn;
this.nbOfPage = nbOfPage;
this.illustrations = illustrations;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getIsbn() {
return isbn;
}
public void setIsbn(String isbn) {
this.isbn = isbn;
}
public Integer getNbOfPage() {
return nbOfPage;
}
public void setNbOfPage(Integer nbOfPage) {
this.nbOfPage = nbOfPage;
}
public Boolean getIllustrations() {
return illustrations;
}
public void setIllustrations(Boolean illustrations) {
this.illustrations = illustrations;
}
}
主要功能在这里：
package com.apress.javaee6.chapter02;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
public class Main {
/**
* @param args
*/
public static void main(String[] args) {
// Create an instance of book
Book book = new Book();
book.setTitle("The Hitchhiker's guide to the Galaxy");
book.setPrice(12.5F);
book.setDescription("Science fiction comedy book");
book.setIsbn("1-84023-742-2");
book.setIllustrations(false);
// Gets an entity manager and a transaction
EntityManagerFactory emf = Persistence.createEntityManagerFactory("chapter02PU");
EntityManager em = emf.createEntityManager();
// Persists the book to the database
EntityTransaction tx = em.getTransaction();
try {
tx.begin();
em.persist(book);
tx.commit();
em.close();
emf.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
问题是无法识别“persistence.xml”。如何让 Maven 指向“persistence.xml”文件？
当我激活 Maven 控制台和“更新依赖项”时，我得到了以下（错误的）信息：
28/06/10 15:20:36 CEST: [INFO] Using 'UTF-8' encoding to copy filtered resources.
28/06/10 15:20:36 CEST: [INFO] skip non existing resourceDirectory /home/zakaria/workspace/chapter02/src/main/resources
28/06/10 15:20:36 CEST: [INFO] Using 'UTF-8' encoding to copy filtered resources.
28/06/10 15:20:36 CEST: [INFO] skip non existing resourceDirectory /home/zakaria/workspace/chapter02/src/test/resources
所以我认为他试图在某个地方创建“资源”目录并且在构建后无法获取它们。
非常感谢；）问候