的EntityManager是空

我新的EJB，創造有趣的應用程序/學習EJB以下是代碼。的EntityManager是空

@Entity 
@Table(name = "PERSON", schema = "experiment") 
@NamedQuery(name = "Person.fetchAllPerson" , query = "select p from Person p") 
public class Person implements Serializable { 

    private static final long serialVersionUID = 1L; 
    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    @Column(name = "id") 
    private Long id; 
    @Column(name = "name", length = 500) 
    private String name; 
    @Column(name = "age") 
    private Integer age; 

    public Long getId() { 
     return id; 
    } 

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

    public String getName() { 
     return name; 
    } 

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

    public Integer getAge() { 
     return age; 
    } 

    public void setAge(Integer age) { 
     this.age = age; 
    } 

    @Override 
    public int hashCode() { 
     int hash = 0; 
     hash += (id != null ? id.hashCode() : 0); 
     return hash; 
    } 

    @Override 
    public boolean equals(Object object) { 
     // TODO: Warning - this method won't work in the case the id fields are not set 
     if (!(object instanceof Person)) { 
      return false; 
     } 
     Person other = (Person) object; 
     if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) { 
      return false; 
     } 
     return true; 
    } 

    @Override 
    public String toString() { 
     return "Person id ::: "+this.id + " | "+"name ::: "+this.name+" | "+"age ::: "+this.age; 
    } 
}

以上是實體類::: 下面是我的豆（會話Bean）::

@Stateless 
public class PersonSessionBean implements PersonSessionBeanLocal { 

    @PersistenceContext(unitName = "OCDPU") 
    private EntityManager em; 

    private static final Logger LOGGER = Logger.getLogger(PersonSessionBean.class); 

    public void addPerson(Person p) { 
     LOGGER.info("ENTITY MANAGER ::: "+em); 
     em.persist(p); 
    } 

    public static PersonSessionBean getPersonSessionBean() { 
     return new PersonSessionBean(); 
    } 
}

下面

是我的persistence.xml :::

<?xml version="1.0" encoding="UTF-8"?> 
<persistence version="2.0" 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_2_0.xsd"> 
    <persistence-unit name="OCDPU" transaction-type="JTA"> 
    <provider>org.hibernate.ejb.HibernatePersistence</provider> 
    <jta-data-source>java:/jndi_postgresql2</jta-data-source> 
    <exclude-unlisted-classes>false</exclude-unlisted-classes> 
    <properties> 
     <property name="hibernate.hbm2ddl.auto" value="create-drop"/> 
     <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" /> 
     <property name="hibernate.show_sql" value="true" /> 
    </properties> 
    </persistence-unit> 
</persistence>

以下是我的.zul文件控制器:::

public class Index2Controller extends GenericForwardComposer<Component> { 

    private final static Logger LOGGER = Logger.getLogger(Index2Controller.class); 

    private Textbox idTB,personTB,ageTB; 
    private Button btn; 
    private Window win; 

// @Inject 
// private PersonDao pd; 

    private PersonSessionBean psb; 

    { 
     psb = PersonSessionBean.getPersonSessionBean(); 
     LOGGER.info("PersonSessionBean ::: "+psb); 
    } 

    public void onClick$btn(Event e) { 
     if(personTB.getText().equals("") ||ageTB.getText().equals("")){ 
      //| idTB.getText().equals("")) { 
      this.alert("Enter all values"); 
      return; 
     } 

     LOGGER.info("ONCLICK ::: PersonSessionBean ::: "+this.psb); 

     Integer i; 
     i = Integer.valueOf(Integer.parseInt(ageTB.getText())); 
     Person p = new Person(); 
     p.setName(personTB.getText()); 
     p.setAge(i); 
     LOGGER.error("Person is ::: "+p); 
     psb.addPerson(p); 
     personTB.setRawValue(null); 
     ageTB.setRawValue(null); 
     showNotification("Saved", win); 
    } 

    public void showNotification(String msg, Component ref) { 
     Clients.showNotification(msg, "info", ref, 700, 0, 1000); 
    } 
}

的錯誤::::

18:33:27,395 INFO [com.discusit.ctrl.Index2Controller] (http--0.0.0.0-8080-5) ONCLICK ::: PersonSessionBean ::: [email protected] 
18:33:27,396 ERROR [com.discusit.ctrl.Index2Controller] (http--0.0.0.0-8080-5) Person is ::: Person id ::: null | name ::: Naman | age ::: 26 
18:33:27,397 INFO [com.discusit.bean.PersonSessionBean] (http--0.0.0.0-8080-5) ENTITY MANAGER ::: null 
18:33:27,400 SEVERE [org.zkoss] (http--0.0.0.0-8080-5) >>java.lang.NullPointerException 
>> at com.discusit.bean.PersonSessionBean.addPerson(PersonSessionBean.java:27) 
>> at com.discusit.ctrl.Index2Controller.onClick$btn(Index2Controller.java:60) 
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
>> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
>> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
>> at java.lang.reflect.Method.invoke(Method.java:606) 
>> at org.zkoss.zk.ui.event.GenericEventListener.onEvent(GenericEventListener.java:88) 
>> at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:2742) 
>> at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2713) 
>> at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2654) 
>> at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:136) 
>> at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:325) 
>> at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:348) 
>> at org.zkoss.zk.ui.AbstractComponent$ForwardListener.onEvent(AbstractComponent.java:3180) 
>> at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:2742) 
>> at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2713) 
>> at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2654) 
>> at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:136) 
>> at org.zkoss.zk.ui.impl.UiEngineImpl.processEvent(UiEngineImpl.java:1717) 
>> at org.zkoss.zk.ui.impl.UiEngineImpl.process(UiEngineImpl.java:1502) 
>> at org.zkoss.zk.ui.impl.UiEngineImpl.execUpdate(UiEngineImpl.java:1212) 
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.process(DHtmlUpdateServlet.java:600) 
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.doGet(DHtmlUpdateServlet.java:482) 
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.doPost(DHtmlUpdateServlet.java:491) 
>> at javax.servlet.http.HttpServlet.service(HttpServlet.java:754) 
>> at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) 
>> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) 
>> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) 
>> at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:62) 
>> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) 
>> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) 
>> at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) 
>> at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) 
>> at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) 
>> at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) 
>> at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) 
>> at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) 
>> at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) 
>> at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) 
>> at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) 
>> at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) 
>> at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) 
>> at java.lang.Thread.run(Thread.java:724)

我使用JBoss AS 7.1.1 final.In我創建pool.Which連接到我的數據庫在我的局域網連接。無法弄清楚什麼是錯的。先謝謝你。

我想我缺少的pom.xml 這裏的東西是我的POM :::

<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.discusit</groupId> 
    <artifactId>OrgChartDemo</artifactId> 
    <version>1.0</version> 
    <packaging>war</packaging> 

    <name>OrgChartDemo</name> 

    <properties> 
     <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir> 
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 
    </properties> 

    <dependencies> 
     <dependency> 
      <groupId>javax</groupId> 
      <artifactId>javaee-web-api</artifactId> 
      <version>6.0</version> 
      <scope>provided</scope> 
     </dependency> 

     <!-- ZK DEPENDENCIES --> 
     <dependency> 
      <groupId>org.zkoss.zk</groupId> 
      <artifactId>zkplus</artifactId> 
      <version>6.5.2</version> 
     </dependency> 
     <dependency> 
      <groupId>org.zkoss.zk</groupId> 
      <artifactId>zhtml</artifactId> 
      <version>6.5.2</version> 
     </dependency> 
     <dependency> 
      <groupId>org.zkoss.zk</groupId> 
      <artifactId>zkbind</artifactId> 
      <version>6.5.2</version> 
     </dependency> 
     <dependency> 
      <groupId>org.zkoss.zk</groupId> 
      <artifactId>zul</artifactId> 
      <version>6.5.2</version> 
     </dependency> 
     <!-- ZK Dependencies ends --> 

     <!-- log4j --> 
     <dependency> 
      <groupId>log4j</groupId> 
      <artifactId>log4j</artifactId> 
      <version>1.2.17</version> 
     </dependency> 
     <!-- log4j ends --> 

     <!-- javax.persistence 2.0 implementation --> 
     <dependency> 
      <groupId>org.hibernate.javax.persistence</groupId> 
      <artifactId>hibernate-jpa-2.0-api</artifactId> 
      <version>1.0.1.Final</version> 
     </dependency> 
     <!-- javax.persistence 2.0 ends --> 
    </dependencies> 

    <build> 
     <plugins> 
      <plugin> 
       <groupId>org.apache.maven.plugins</groupId> 
       <artifactId>maven-compiler-plugin</artifactId> 
       <version>2.3.2</version> 
       <configuration> 
        <source>1.6</source> 
        <target>1.6</target> 
        <compilerArguments> 
         <endorseddirs>${endorsed.dir}</endorseddirs> 
        </compilerArguments> 
       </configuration> 
      </plugin> 
      <plugin> 
       <groupId>org.apache.maven.plugins</groupId> 
       <artifactId>maven-war-plugin</artifactId> 
       <version>2.1.1</version> 
       <configuration> 
        <failOnMissingWebXml>false</failOnMissingWebXml> 
       </configuration> 
      </plugin> 
      <plugin> 
       <groupId>org.apache.maven.plugins</groupId> 
       <artifactId>maven-dependency-plugin</artifactId> 
       <version>2.1</version> 
       <executions> 
        <execution> 
         <phase>validate</phase> 
         <goals> 
          <goal>copy</goal> 
         </goals> 
         <configuration> 
          <outputDirectory>${endorsed.dir}</outputDirectory> 
          <silent>true</silent> 
          <artifactItems> 
           <artifactItem> 
            <groupId>javax</groupId> 
            <artifactId>javaee-endorsed-api</artifactId> 
            <version>6.0</version> 
            <type>jar</type> 
           </artifactItem> 
          </artifactItems> 
         </configuration> 
        </execution> 
       </executions> 
      </plugin> 
     </plugins> 
    </build> 
</project>

來源

2013-07-24 Bilbo Baggins

資源注入是這樣的：

@PersistenceContext(unitName = "OCDPU") 
private EntityManager em;

僅適用於客戶端類，它的生命週期由容器管理，即EJB，JSF ManagedBean，CDI bean或servlet。在你的情況下，客戶端類PersonSessionBean是EJB，這是很正常的。該錯誤是在PersonSessionBean的實例：

psb = PersonSessionBean.getPersonSessionBean();

此行是錯誤的，因爲EJB應通過@EJB註解要麼注入：

@EJB PersonSessionBean psb;

，或者通過JNDI查找檢索。

但你也必須意識到，客戶端類Index2Controller是容器管理太強了，從代碼貼吧看起來並非如此。

有用的鏈接：Accessing Enterprise Beans從Oracle的Java EE 6教程。

來源

2013-07-24 13:33:20 perissf

客戶端類Index2Controller由ZK引擎管理，而不是由容器，這就是爲什麼我寫了SB = PersonSessionBean.getPersonSessionBean）的原因（;我沒有找到任何其他方式來獲得一個不受容器管理的類。感謝您回覆 –

如果您仔細查看堆棧跟蹤的第一行，它自己說PersonSessionBean正在創建，問題在於注入實體管理器。感謝回覆。 –

是的，但由於上述原因實體管理器注入失敗。不幸的是，我不能再幫忙解決這個問題，因爲我從未與ZK合作過。 – perissf

的EntityManager是空

回答

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