EJB持久性不起作用

Question

我有一個在Jboss 5GA，JDK 6上運行的帶有EJB模塊的EJB持久性示例。 默認包有3個文件：

Book.java：

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="books")
public class Book implements Serializable{

   private int id;
   private String name;

   public Book(){        
   }

   @Id
   @GeneratedValue(strategy= GenerationType.IDENTITY)
   @Column(name="id")
   public int getId() {
      return id;
   }

   public void setId(int id) {
      this.id = id;
   }

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }    
}

LibraryPersistentBean.java

import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Stateless
public class LibraryPersistentBean implements LibraryPersistentBeanRemote {



   @PersistenceContext(unitName="EJBModule1PU")
   private EntityManager entityManager;         

   @Override
   public void addBook(Book book) {
      entityManager.persist(book);
   }    

   @Override
   public List<Book> getBooks() {
      return entityManager.createQuery("From books").getResultList();
   }
}

LibraryPersistentBeanRemote.java：

import java.util.List;
import javax.ejb.Remote;

@Remote
public interface LibraryPersistentBeanRemote {

   void addBook(Book bookName);

   List<Book> getBooks();

}

配置文件是persistence.xml和jboss-ds.xml，它們具有以下代碼行：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
  <persistence-unit name="EJBModule1PU" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>java:/MysqlDS</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="hibernate.hbm2ddl.auto" value="update"/>
    </properties>
  </persistence-unit>
</persistence>

<?xml version="1.0" encoding="UTF-8"?>
<datasources>
  <local-tx-datasource>
    <jndi-name>MysqlDS</jndi-name>
    <connection-url>jdbc:mysql://localhost:3306/ejb_books?zeroDateTimeBehavior=convertToNull</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <user-name>root</user-name>
    <password/>
    <min-pool-size>5</min-pool-size>
    <max-pool-size>20</max-pool-size>
    <idle-timeout-minutes>5</idle-timeout-minutes>
  </local-tx-datasource>
</datasources>

客戶的申請包括：

import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;


public class JavaApplication1 {

   public static void main(String[] args) throws NamingException {

       try {
            Book b = new Book();
            b.setName("AI");

            Properties env = new Properties();
            env.put(Context.INITIAL_CONTEXT_FACTORY,"org.jnp.interfaces.NamingContextFactory");
            env.put(Context.URL_PKG_PREFIXES,"org.jboss.naming:org.jnp.interfaces");
            env.put(Context.PROVIDER_URL, "jnp://localhost:1099");

            Context ctx = new InitialContext(env);

            LibraryPersistentBeanRemote libraryBean = (LibraryPersistentBeanRemote)ctx.lookup("LibraryPersistentBean/remote");

            libraryBean.addBook(b);
       } catch (NamingException ex) {
            Logger.getLogger(JavaApplication1.class.getName()).log(Level.SEVERE, null, ex);
       }
   }

} 

和jboss-client.jar，EJB模塊已導入

運行時發生錯誤：

Mar 7, 2017 10:30:23 AM JavaApplication1 main
SEVERE: null
javax.naming.NoInitialContextException: Cannot instantiate class: org.jnp.interfaces.NamingContextFactory [Root exception is java.lang.ClassNotFoundException: org.jnp.interfaces.NamingContextFactory]
    at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:657)
    at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
    at javax.naming.InitialContext.init(InitialContext.java:223)
    at javax.naming.InitialContext.<init>(InitialContext.java:197)
    at JavaApplication1.main(JavaApplication1.java:25)
Caused by: java.lang.ClassNotFoundException: org.jnp.interfaces.NamingContextFactory
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:247)
    at com.sun.naming.internal.VersionHelper12.loadClass(VersionHelper12.java:46)
    at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:654)
    ... 4 more

如何解決這些錯誤？ 非常感謝 ！

Answer 1

“ $ JBOSS_HOME / jboss-as / client / jnp-client.jar”包含缺少的類“ org.jnp.interfaces.NamingContextFactory”，“ jnp-client.jar”在內部使用MANIFEST.MF文件“ class- “ $ JBOSS_HOME / client / jbossall-client.jar”文件中的“路徑”條目。

因此，JBoss客戶端代碼用戶/開發人員需要確保避免“ [[由以下原因引起：java.lang.ClassNotFoundException：org.jnp.interfaces.NamingContextFactory]”異常用戶必須包括“ $ JBOSS_HOME / client / jbossall -client.jar”在客戶的類路徑中。