Enterprise JavaBeans 组件和 CORBA 客户端：开发者指南

javax.rmi

开发访问 Enterprise JavaBean 组件的 CORBA 客户端

第 1 部分：编写 Enterprise JavaBean 组件

/Java/src/ejbinterop

Logger.java

LoggerHome.java

LoggerEJB.java

LogMessage.java。

Logger.java

Logger.java

EJBObject

//Code Example 1: Logger.java
packageejbinterop;

importjavax.ejb.EJBObject;
importjava.rmi.RemoteException;

/**
* Accepts simple String log messages and prints
* them on the server.
*/
public interface Logger extends EJBObject
{
/**
* Logs the given message on the server with
* the current server time.
*/
void logString(String message) throws RemoteException;
}

LoggerHome.java

LoggerHome.java

EJBHome

EJBHome

//Code Example 2: LoggerHome.java
packageejbinterop;

importjava.rmi.RemoteException;
importjavax.ejb.EJBHome;
importjavax.ejb.CreateException;

public interface LoggerHome extends EJBHome
{
Logger create() throws RemoteException, CreateException;
}

LoggerEJB.java

LoggerEJB.java

//LoggerEJB.java
packageejbinterop;

importjavax.ejb.*;
importjava.util.*;
importjava.rmi.*;
importjava.io.*;

/**
* Accepts simple String log messages and prints
* them on the server.
*/
public class LoggerEJB implements SessionBean {

public LoggerEJB() {}
public void ejbCreate() {}
public void ejbRemove() {}
public void ejbActivate() {}
public void ejbPassivate() {}
public void setSessionContext(SessionContext sc) {}

/**
* Logs the given message on the server with
* the current server time.
*/
public void logString(String message) {
LogMessage msg = new LogMessage(message);

System.out.println(msg);
}
}

LogMessage.java

LogMessage.java

//LogMessage.java
packageejbinterop;

importjava.io.Serializable;
importjava.util.Date;
importjava.text.*;

/**
* Simple message class that handles pretty
* printing of log messages.
*/
public class LogMessage implements Serializable
{
private String message;
private long datetime;

/**
* Constructor taking the message. This will
* take the current date and time.
*/
public LogMessage(String msg) {
message = msg;
datetime = (new Date()).getTime();
}

/**
* Creates a formatted String showing the message.
*/
public String toString() {
StringBuffer sbuf = new StringBuffer();
DateFormat dformat
= DateFormat.getDateTimeInstance(DateFormat.MEDIUM,
DateFormat.LONG);
FieldPosition fpos = new
FieldPosition(DateFormat.DATE_FIELD);
dformat.format(new Date(datetime), sbuf, fpos);
sbuf.append(": ");
sbuf.append(message);
return sbuf.toString();
}
}

javac -classpath $J2EE_HOME/lib/j2ee.jar:.. *.java

第 2 部分：生成 CORBA IDL

rmic

rmic

rmic -idl -noValueMethods -classpath
$J2EE_HOME/lib/j2ee.jar:<path_to_ejbinterop_dir>
-d <path_to_where_idl_files_should_be_generated>
ejbinterop.Loggerejbinterop.LoggerHome

ejbinterop

javax.ejb

.jar

$J2EE_HOME/lib/j2ee.jar

rmic

noValueMethods

rmic

rmic

rmic

java/lang/Ex.idl

java/lang/Exception.idl

java/lang/Object.idl

java/lang/Throwable.idl

java/lang/ThrowableEx.idl

javax/ejb/CreateEx.idl

javax/ejb/CreateException.idl

javax/ejb/EJBHome.idl

javax/ejb/EJBMetaData.idl

javax/ejb/EJBObject.idl

javax/ejb/Handle.idl

javax/ejb/HomeHandle.idl

javax/ejb/RemoveEx.idl

javax/ejb/RemoveException.idl

ejbinterop/Logger.idl

ejbinterop/LoggerHome.idl

EJBMetaData

rmic

Ex

http://java.sun.com/j2se/1.4.2/docs/guide/idl/jidlExceptions.html

第 3 部分：创建 CORBA 客户端

LoggerHome

corbaname

include

corbaname

corbaname

LoggerHome

LoggerHome

LoggerEJB

//Code Example: Client.cpp
#include <fstream.h>

// C++ ORB Vendor specific include files
// These are from C++ ORBacus 4.0.5

#include <OB/CORBA.h>
#include <OB/OBORB.h>

// Include files generated from our IDL
#include <java/lang/Exception.h>
#include <java/lang/Throwable.h>
#include <javax/ejb/CreateException.h>
#include <javax/ejb/RemoveException.h>
#include <ejbinterop/Logger.h>
#include <ejbinterop/LoggerHome.h>

/**
* Given an ORB and a corbaname URL for a LoggerHome
* object, logs a simple string message on the server.
*/
void
run(CORBA::ORB_ptr orb, const char* logger_home_url)
{
cout << "Looking for: " << logger_home_url << endl;

// Look up the LoggerHome object in the naming context
// pointed to by the corbaname URL
CORBA::Object_var home_obj
= orb->string_to_object(logger_home_url);

// Perform a safe downcast
ejbinterop::LoggerHome_var home
=ejbinterop::LoggerHome::_narrow(home_obj.in());

assert(!CORBA::is_nil(home));

// Create a Logger EJB reference
ejbinterop::Logger_var logger = home->create();

CORBA::WStringValue_var msg =
new CORBA::WStringValue((const CORBA::WChar*)L"Message
from a C++ client");

cout << "Logging..." << endl;

// Log our message
logger->logString(msg);

// Tell the application server we won't use this
// EJB reference any more
logger->remove();

cout << "Done" << endl;
}

/**
* Simple main method that checks arguments, creates an
* ORB, and handles exceptions.
*/
int
main(int argc, char* argv[])
{
int exit_code = 0;
CORBA::ORB_var orb;

try {

// Check the arguments
if (argc != 2) {
cerr << "Usage: Client <corbaname URL of LoggerHome>" << endl;
return 1;
}

// Create an ORB
orb = CORBA::ORB_init(argc, argv);

// Register value factories

// NOTE: This is overkill for the example since we'll never
// get these exceptions.  Also, the _OB_id method is a
// proprietary feature of ORBacus C++ generated code.
CORBA::ValueFactory factory = newjava::lang::Throwable_init;
orb -> register_value_factory(java::lang::Throwable::_OB_id(),
factory);
factory -> _remove_ref();

factory = newjava::lang::Exception_init;
orb -> register_value_factory(java::lang::Exception::_OB_id(),
factory);
factory -> _remove_ref();

factory = newjavax::ejb::CreateException_init;
orb -> 		    register_value_factory(javax::ejb::CreateException::_OB_id(),
factory);
factory -> _remove_ref();

factory = newjavax::ejb::RemoveException_init;
orb ->
register_value_factory(javax::ejb::RemoveException::_OB_id(),
factory);
factory -> _remove_ref();

// Perform the work
run(orb, argv[1]);

} catch(const CORBA::Exception& ex) {
// Handle any CORBA related exceptions
cerr << ex._to_string() << endl;
exit_code = 1;
}

// Release any ORB resources
if (!CORBA::is_nil(orb)) {
try {
orb -> destroy();
} catch(const CORBA::Exception& ex) {
cerr << ex._to_string() << endl;
exit_code = 1;
}
}

return exit_code;
}

第 4 部分：部署 Enterprise JavaBean 组件

LoggerEJB

$J2EE_HOME/bin/j2ee -verbose

$J2EE_HOME/bin/deploytool

File

->

New

->

Application。

Logger.ear

Logger。

File

->

New

->

Enterprise Bean。

.class

ejbinterop

Logger.class

LoggerHome.class

LoggerEJB.class

LogMessage.class

Stateless

Session

Bean

Type。

ejbinterop.LoggerEJB

Enterprise

Bean

Class

ejbinterop.LoggerHome

Remote

Home

Interface

ejbinterop.Logger

Remote

Interface

Security

Settings

Deployment

Settings

Support

Client

Choice

Tools

->

Deploy。

JNDI

Name

ejbinterop/logger

LoggerEJB

第 5 部分：运行客户端可执行文件

Client corbaname:iiop:1.2@localhost:1050#ejbinterop/logger

Client

corbaname

iiop:1.2

localhost

localhost

1050

Client corbaname:iiop:1.2@localhost:1050

ejbinterop/logger

Sep 21, 2001 3:33:07 PM PDT: Message from a C++ client[code]ejbinterop/
logger

第 6 部分：停止 J2EE 服务器

$J2EE_HOME/bin/j2ee -stop

创建 Java RMI-IIOP 客户端应用程序

.jar

.jar

Return Client Jar

LoggerEJB

//Code Example: LogClient.java
packageejbinterop;

importjava.rmi.RemoteException;
importjavax.rmi.*;
importjava.io.*;
importjavax.naming.*;
importjavax.ejb.*;

/**
* Simple Java RMI-IIOP client that uses an EJB component.
*/
public class LogClient
{
/**
* Given a corbaname URL for a LoggerHome,
* log a simple String message on the server.
*/
public static void run(String loggerHomeURL)
throws CreateException, RemoveException,
RemoteException, NamingException
{
System.out.println("Looking for: " + loggerHomeURL);

// Create an InitialContext. This will use the
// CosNaming provider we will specify at runtime.
InitialContext ic = new InitialContext();

// Lookup the LoggerHome in the naming context
// pointed to by the corbaname URL
Object homeObj = ic.lookup(loggerHomeURL);

// Perform a safe downcast
LoggerHome home
= (LoggerHome)PortableRemoteObject.narrow(homeObj,
LoggerHome.class);

// Create a Logger EJB reference
Logger logger = home.create();

System.out.println("Logging...");

// Log our message
logger.logString("Message from a Java RMI-IIOP client");

// Tell the application server we won't use this
// EJB reference anymore
logger.remove();

System.out.println("Done");
}

/**
* Simple main method to check arguments and handle
* exceptions.
*/
public static void main(String args[])
{
try {

if (args.length != 1) {
System.out.println("Args: corbaname URL of LoggerHome");
System.exit(1);
}

LogClient.run(args[0]);

} catch (Throwable t) {
t.printStackTrace();
System.exit(1);
}
}
}

使用 Java RMI-IIOP 客户端运行应用程序

ejbinterop

java

javac -classpath $J2EE_HOME/lib/j2ee.jar:<ejbinterop_directory> *.java

java -classpath $J2EE_HOME/lib/j2ee.jar:
<path to LoggerClient.jar>/LoggerClient.jar:
<directory_above_ejbinterop>:<ejbinterop_directory>
ejbinterop.LogClient
corbaname:iiop:1.2@localhost:1050#ejbinterop/logger

Jan 31, 2002 2:27:47 PM PST: Message from a Java RMI-IIOP client

Looking for: corbaname:iiop:1.2@localhost:1050#ejbinterop/logger
Logging...
Done

超越基本应用程序

如何增强应用程序

rmic

-noValueMethods

Logger

LogMessage

针对复杂接口的技巧

java.util

LogMessage

链接到类似例子