转换器@FacesConverter（forClass = [someClass.class]）可以实现为@Singleton @Lock（READ）吗？

时间：2013-04-13 11:50:41

标签： java-ee singleton converter openejb apache-tomee

为了在整个app中删除'static'声明（以帮助JVM的GC），我从下面的Converter类的定义中删除了'static'。所以这导致了下面的臭名昭着的错误：

Apr 13, 2013 4:10:38 AM org.apache.myfaces.application.ApplicationImpl internalCreateConverter
SEVERE: Could not instantiate converter jsf.CustomerController$CustomerControllerConverter
java.lang.InstantiationException: jsf.CustomerController$CustomerControllerConverter
    at java.lang.Class.newInstance0(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at org.apache.myfaces.application.ApplicationImpl.internalCreateConverter(ApplicationImpl.java:1626)
    at org.apache.myfaces.application.ApplicationImpl.createConverter(ApplicationImpl.java:1545)
    at javax.faces.application.ApplicationWrapper.createConverter(ApplicationWrapper.java:158)

我认为'static'是必要的，因为每个应用程序只创建一个类的副本。正确？那么，我可以将类定义为@Singleton @Lock（READ）来解决问题吗？

根据NetBeans生成的JSF控制器/ bean代码，Converter通常在与控制器或@ManagedBean相同的.java文件中定义。老实说，我不想在xhtml中使用addConverter（）或converterId =“...”。我更喜欢使用@FacesConverter，因为这在整个应用程序中都适用于我。

package jsf;

import jpa.entities.Customer;
import jpa.session.CustomerFacade;

import java.io.Serializable;
import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;

@ManagedBean(name = "customerController")
@RequestScoped
public class CustomerController implements Serializable {

    @EJB
    private jpa.session.CustomerFacade ejbFacade;

    public CustomerController() {
    }

    @FacesConverter(forClass = Customer.class)
    public class CustomerControllerConverter implements Converter {

        public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
            if (value == null || value.length() == 0) {
                return null;
            }
            /*
             * 2012-07-10 when user enters invalid/incomplete value (e.g. "irene", see below) in AutoComplete
             *
            WARNING: For input string: "irene"
            java.lang.NumberFormatException: For input string: "irene"
                    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
                    at java.lang.Integer.parseInt(Integer.java:492)
                    at java.lang.Integer.valueOf(Integer.java:582)
                    at jsf.pointOfContact.pf_PointOfContactController$PointOfContactControllerConverter.getKey(pf_PointOfContactController.java:1625)
                    at jsf.pointOfContact.pf_PointOfContactController$PointOfContactControllerConverter.getAsObject(pf_PointOfContactController.java:1620)
                    at org.primefaces.component.autocomplete.AutoCompleteRenderer.getConvertedValue(AutoCompleteRenderer.java:529)
                    at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
                    at javax.faces.component.UIInput.validate(UIInput.java:960)
             *
             */
            try {
                Integer test = getKey(value);
            } catch (java.lang.NumberFormatException e) {
                return null;
            }
            CustomerController controller = (CustomerController) facesContext.getApplication().getELResolver().
                    getValue(facesContext.getELContext(), null, "customerController");
            return controller.ejbFacade.find(getKey(value));
        }

        java.lang.Integer getKey(String value) {
            java.lang.Integer key;
            key = Integer.valueOf(value);
            return key;
        }

        String getStringKey(java.lang.Integer value) {
            StringBuffer sb = new StringBuffer();
            sb.append(value);
            return sb.toString();
        }

        public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
            if (object == null) {
                return null;
            }
            if (object instanceof Customer) {
                Customer o = (Customer) object;
                return getStringKey(o.getCustomerId());
            } else {
                throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + Customer.class.getName());
            }
        }
    }
}

请告知。

另外，如果有人在stackoverflow.com上回复我的问题，请告诉我如何收到电子邮件通知。

谢谢！

1 个答案:

答案 0 :(得分：0)

答案是肯定的，在JNDI查找的帮助下。

我刚刚从JSF @RequestScoped CustomerController中删除了CustomerControllerConverter，创建了转换器类，用@Singleton @Lock（READ）标记它，并通过JNDI查找引用了@Stateless EJB。见下文。

package converter;

import java.util.concurrent.TimeUnit;

import javax.ejb.AccessTimeout;
import javax.ejb.Lock;
import javax.ejb.LockType;
import javax.ejb.Singleton;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;

import javax.naming.InitialContext;

import jpa.entities.Customer;
import jpa.session.CustomerFacade;


/**
 *
 * @author Administrator
 */
@Singleton
@Lock(LockType.READ)
@AccessTimeout(value = 1, unit = TimeUnit.MINUTES)
@FacesConverter(forClass = Customer.class)
public class CustomerConverter implements Converter {

    public CustomerConverter() {

    }

    public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
        if (value == null || value.length() == 0) {
            return null;
        }
        /*
         * 2012-07-10 when user enters invalid/incomplete value (e.g. "irene", see below) in AutoComplete
         *
        WARNING: For input string: "irene"
        java.lang.NumberFormatException: For input string: "irene"
                at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
                at java.lang.Integer.parseInt(Integer.java:492)
                at java.lang.Integer.valueOf(Integer.java:582)
                ...
                ...
                at org.primefaces.component.autocomplete.AutoCompleteRenderer.getConvertedValue(AutoCompleteRenderer.java:529)
                at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
                at javax.faces.component.UIInput.validate(UIInput.java:960)
         *
         */
        try {
            Integer test = getKey(value);
        } catch (java.lang.NumberFormatException e) {
            return null;
        }
        Object object = null;
        CustomerFacade ejbFacade;
        try {
            InitialContext ic = new InitialContext();
            ejbFacade = (CustomerFacade) ic.lookup("java:global/appWARFileNameOrAppContextName/CustomerFacade");
            if (ejbFacade == null) {
                System.err.println("CustomerConverter.getAsObject(): ejbFacade = null)");
                return null;
            }
        } catch (Exception e) {
            System.err.println("CustomerConverter.getAsObject(): error on JNDI lookup of CustomerFacade");
            e.printStackTrace();
            return null;
        }
        try {
            object = ejbFacade.find(getKey(value));
        } catch (Exception e) {
            System.err.println("CustomerConverter.getAsObject(): error on ejbFacade.find(getKey(value))");
            e.printStackTrace();
            return null;
        }
        return object;
    }

    java.lang.Integer getKey(String value) {
        java.lang.Integer key;
        key = Integer.valueOf(value);
        return key;
    }

    String getStringKey(java.lang.Integer value) {
        StringBuffer sb = new StringBuffer();
        sb.append(value);
        return sb.toString();
    }

    public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
        if (object == null) {
            return null;
        }
        if (object instanceof Customer) {
            Customer o = (Customer) object;
            return getStringKey(o.getCustomerId());
        } else {
            throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + Customer.class.getName());
        }
    }
}

经验教训：无法通过以下方式引用或实例化ejbFacade：

@注入， @EJB， BeanManager

参考文献：

Oracle博客

  1. Ken Saks's Blog: Application-specified Portable JNDI Names
  2. Ken Saks's Blog: Portable Global JNDI Names

    3. TomEE JavaEE示例 - 引用EJB

    1. Injection Of Ejbs
    2. Lookup Of Ejbs with Descriptor
    3. Lookup Of Ejbs

      4. 最终，我不得不引用Glassfish的server.log文件（参考实现（RI））来查看我的@Stateless EJB的JNDI查找路径示例，因为我使用的是Glassfish，过去。 ：）

      <强>更新

      您还可以在TomEE / catalina日志中找到可移植的全局JNDI名称。它将如下所示。

      Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=CustomerFacadeLocalBean) --> Ejb(deployment-id=CustomerFacade)

Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=global/webApp/CustomerFacade!jpa.session.CustomerFacade) --> Ejb(deployment-id=CustomerFacade)

Apr 13, 2013 10:00:58 AM org.apache.openejb.assembler.classic.JndiBuilder bind
INFO: Jndi(name=global/webApp/CustomerFacade) --> Ejb(deployment-id=CustomerFacade)

      其中＆＃39; webApp＆＃39;在全局JNDI名称中可能是您​​的WAR文件名或可能是EJB JAR文件名等...

      希望这有助于其他人！

相关问题
最新问题