通用类中的JPAContainer？

Question

我正在尝试创建一个通用类以在项目中自动创建jpacontainer，但无法正常工作并返回一些错误。 错误信息未设置EntityProvider。

我正在尝试这个。

/** class init jpacontainer */
public class PersistJPAContainer<T> extends JPAContainer<T>{
private static final long serialVersionUID = 1L;
private static final String PERSISTENCE_UNITNAME = "ps_unitname";

public PersistJPAContainer(Class<T> entityClass) {
    super(entityClass);
    JPAContainer<?> container = JPAContainerFactory.make(entityClass, PERSISTENCE_UNITNAME);
}

}

/** my app UI */
public class AcademiaonlineUI extends UI {
    private final JPAContainer<Empresa> datasource = new PersistJPAContainer<Empresa>(Empresa.class);

@Override
protected void init(VaadinRequest request) {
    Table tabela = new Table("Empresa", datasource);
    VerticalLayout vLayout = new VerticalLayout();

    vLayout.addComponent(tabela);
    setContent(vLayout);
}

}

/** errors */
Mar 17, 2014 11:14:30 AM com.vaadin.server.DefaultErrorHandler doDefault
SEVERE: 
java.lang.IllegalStateException: No EntityProvider has been set
    at com.vaadin.addon.jpacontainer.JPAContainer.doGetEntityProvider(JPAContainer.java:313)
    at com.vaadin.addon.jpacontainer.JPAContainer.size(JPAContainer.java:912)
    at com.vaadin.ui.AbstractSelect.size(AbstractSelect.java:762)
    at com.vaadin.ui.Table.refreshRenderedCells(Table.java:1654)
    at com.vaadin.ui.Table.attach(Table.java:4171)
    at com.vaadin.server.AbstractClientConnector.attach(AbstractClientConnector.java:583)
    at com.vaadin.ui.AbstractComponent.attach(AbstractComponent.java:572)
    at com.vaadin.ui.AbstractComponent.setParent(AbstractComponent.java:479)
    at com.vaadin.ui.AbstractSingleComponentContainer.setContent(AbstractSingleComponentContainer.java:137)
    at com.vaadin.ui.UI.setContent(UI.java:1162)
    at br.com.academiaonline.AcademiaonlineUI.init(AcademiaonlineUI.java:24)
    at com.vaadin.ui.UI.doInit(UI.java:614)
    at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:223)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:73)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:37)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1382)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:238)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:724)



//persistence.xml
<?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="ps_unitname" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>br.com.academiaonline.beans.Empresa</class>

    <properties>
        <property name="javax.persistence.jdbc.driver"      value="org.h2.Driver"/>
        <property name="javax.persistence.jdbc.url"         value="jdbc:h2:~/AODB"/>
        <property name="javax.persistence.jdbc.user"        value="sa"/>
        <property name="javax.persistence.jdbc.password"    value="master"/>    

        <!-- Cria a base de dados automaticamente -->       
        <property name="eclipselink.ddl-generation" value="create-or-extend-tables" />      
        <property name="eclipselink.ddl-generation.output-mode" value="database" />

        <!-- Exibe log de erros no console do eclipse -->  
        <property name="eclipselink.logging.level" value="FINE"/>      
   </properties>   
  </persistence-unit>
</persistence>

任何想法 ？

Answer 1

在构造函数中尝试这样的事情

公共类CustomJPA扩展了JPAContainer {

private static final long serialVersionUID = -1752491307148335890L;

private static final String PU_UNIT="ps_unitname";

 public CustomJPA(Class<T> entityClass, String persitenceUnitName) {
           super(entityClass);
           EntityManager  entityManager = JPAContainerFactory.createEntityManagerForPersistenceUnit(persitenceUnitName);
           setEntityProvider(new CachingMutableLocalEntityProvider<T>(entityClass,entityManager));
     }

public CustomJPA(Class<T> entityClass) {
      super(entityClass);
      EntityManager  entityManager =JPAContainerFactory.createEntityManagerForPersistenceUnit(PU_UNIT);
      setEntityProvider(new CachingMutableLocalEntityProvider<T>(entityClass,entityManager));
   }

}

在需要初始化我的容器的任何地方，我都会做这样的事情

 JPAContainer<Bean> myBean= new CustomJPA<Bean>(Bean.class);

希望这可以帮助。 我觉得您正在编写一些冗余代码。

注意：

• 我尚未测试此代码段。
• 尝试使用适当的类作为您的EnityProvider，在此示例中，我使用了默认类

顺便说一句，这是您所期望的吗？

Answer 2

现在可以工作了……经过一些测试终于可以工作了。

我是这样

public class PersistJPAContainer<T> extends JPAContainer<T>{    
private static final long serialVersionUID = 1L;
private static final String PERSISTENCE_UNITNAME = "ps_unitname";

public PersistJPAContainer(Class<T> entityClass) {
    super(entityClass);
    EntityManager em = JPAContainerFactory.createEntityManagerForPersistenceUnit(PERSISTENCE_UNITNAME);
    setEntityProvider(new CachingMutableLocalEntityProvider<T>(entityClass, em));
}   

}

public class AcademiaonlineUI extends UI {
    private final PersistJPAContainer<Empresa> datasource = new PersistJPAContainer<Empresa>(Empresa.class);

和工程！