Question

我是EJB新手，正在尝试＆＃34; Hello World＆＃34; EJB Java程序的类型。这是我的EJB：

package dukesbookstore.ejb;
@Stateless(name="BookRequestBean", mappedName="ejb/BookRequestBean")
@Named
public class BookRequestBean {
    //Other codes here
}

这是我的客户：

    Properties prop = new Properties();
    prop.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.enterprise.naming.SerialInitContextFactory");
    prop.setProperty("org.omg.CORBA.ORBInitialHost", "localhost");
    prop.setProperty("org.omg.CORBA.ORBInitialPort", "3700");
    try {
        InitialContext ctx = new InitialContext(prop);                              
        ctx.lookup("ejb/BookRequestBean");
        System.out.println("EJB Look-up successfull!!");
    } catch (NamingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

但每当我尝试跑步时，我都会遇到异常：

javax.naming.NamingException：＆＃39; ejb / BookRequestBean＆＃39;查找失败在SerialContext中[myEnv = {org.omg.CORBA.ORBInitialPort = 3700，java.naming.factory.initial = com.sun.enterprise.naming.SerialInitContextFactory，org.omg.CORBA.ORBInitialHost = localhost，java

我添加了appserv-rt.jar，gf-client.jar，javaee.jar，但仍然没有运气。任何人都可以帮助我，我在这里缺少什么？我是Glassfish 3.1

Answer 1

这有几个原因：

1）您的EJB未映射到 JNDI 名称。您需要检查是否已成功部署EJB并将其映射到 JNDI 名称。您可以查看Server GUI，Server Log on startup或使用Universal Test Client查看EJB是否已正确映射。请注意，UTC仅显示远程公开的 EJB。

2）您的EJB仅向本地应用程序公开。在这种情况下，远程调用或跨应用程序调用（不同的EAR，WAR ...）将导致EJB失败。在此方案中，创建远程接口并公开它。 本地接口将EJB暴露给本地调用。 远程接口将EJB暴露给远程或跨应用程序调用。

3）您的RMI/IIOP 端口可能不正确。您可以查看Glassfish GUI或Server startup log，了解分配了哪些端口 RMI/IIOP。

注意：要诊断确切的问题，请发布完整的堆栈跟踪。

Answer 2

除了很好的@RaviTrivedi回答，这里有一些想法：

@Named注释
不要同时使用name和mappedName，对于Glassfish，仅使用mappedName
您的EJB应该实现远程接口

Answer 3

添加到@Ravi Trivedi和@Miljen Mikic，如果您使用的是Glassfish，您应该检查您的EJB在JNDI中的注册方式。例如，在Glassfish中键入以下命令：

 asadmin list-jndi-entries

Answer 4

1. your above code works perfectly on glassfish only missing was the remote interface.
2. As suggested above mappedname[vendor specific] and name ....yada yada.....
3. copy below code and run you should be good to go
4. only ensure the *client*.jar is on your path and redeploy the application to glassfish server and run main.

**This Remote interface (the only addition to your above code);**        
            import javax.ejb.Remote;
            
            @Remote
            public interface BookRequestI {
                //Other codes here
                String getISBN();
            }
            
            **your existing implementation spiced with my getISBN() to prove the point :)**
            
            import javax.ejb.Stateless;
            
            
            @Stateless(name="BookRequestBean", mappedName="ejb/BookRequestBean")
            public class BookRequest implements BookRequestI {
                //Other codes here
                @Override
                public String getISBN(){
                    return "ISBN 87 - 11 - 07559 - 7";
                }
            }
            
            **your test as is with my getISBN and typing to interface Type.**
            
            import javax.naming.Context;
            import javax.naming.InitialContext;
            import javax.naming.NamingException;
            import java.util.Properties;
            
            public class BookRequestT {
            
                public static void main(String[] args) {
                   Properties prop = new Properties();
                    prop.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.enterprise.naming.SerialInitContextFactory");
                    prop.setProperty("org.omg.CORBA.ORBInitialHost", "localhost");
                    prop.setProperty("org.omg.CORBA.ORBInitialPort", "3700");
                    try {
            
                        Context ctx = new InitialContext(prop);
                        BookRequestI bookRequest = (BookRequestI) ctx.lookup("ejb/BookRequestBean");
                        System.out.println("EJB Look-up successfull!!" +  bookRequest.getISBN());
                    } catch (NamingException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
            
                }
            }
            
            output:
            EJB Look-up successfull!!ISBN 87 - 11 - 07559 - 7
            
            Process finished with exit code 0

EJB - 'ejb / BookRequestBean'查找失败

4 个答案: