EJB是一种技术规范,遵守这套规范可以使你的程序易读,结构清晰,通用性强,将来的维护费用降低.根据不同的EJB SERVER开发的难度不同,主要是在DEPLOY时编写的代码量.另外在在与数据管理通讯时,可以少编写通用代码.具体应用你可以看看SUN OR ORACLE网站的介绍,那里有例子.我感觉主要用于电子商务.
J2EE 是SUN的JAVA开发平台,它可以用做WEB SERVER AND EJB SERVER
J2EE 是SUN的JAVA开发平台,它可以用做WEB SERVER AND EJB SERVER
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j2ee的平台上。结合websphere。
如果做简单的电子商务,则jsp足够。
//ejb的Home接口
package com.hello;
import java.rmi.*;
import javax.ejb.*;
public interface HelloHome extends EJBHome
{
public Hello create() throws RemoteException, CreateException;
}
//ejb的Remote接口
package com.hello;
import java.rmi.*;
import javax.ejb.*;
public interface Hello extends EJBObject
{
public String sayHello() throws RemoteException;
}
//ejb的bean类
package com.hello;
import java.rmi.*;
import javax.ejb.*;
public class HelloBean implements SessionBean
{
private SessionContext sessionContext;
public void ejbCreate()
{}
public void ejbRemove() throws RemoteException
{}
public void ejbActivate() throws RemoteException
{}
public void ejbPassivate() throws RemoteException
{}
public void setSessionContext(SessionContext sessionContext) throws RemoteException
{
this.sessionContext = sessionContext;
}
public String sayHello()
{
return "Hello, this is a Enterprise Javabean demo!";
}
}
//ejb的客户端,应用服务器weblogic5.1
package com.hello;
import javax.naming.*;
import java.util.Properties;
import javax.rmi.PortableRemoteObject;
public class HelloClient
{
private HelloHome helloHome = null;
private String showMsg;
public HelloClient()
{
try
{
Context ctx = getInitialContext();
Object ref = ctx.lookup("Hello");
helloHome = (HelloHome) PortableRemoteObject.narrow(ref, HelloHome.class);
Hello hello = helloHome.create();
showMsg = hello.sayHello();
System.out.println(showMsg);
hello.remove();
}
catch(Exception e)
{
e.printStackTrace();
}
} private Context getInitialContext() throws Exception
{
String url = "t3://localhost:7001";
String user = null;
String password = null;
Properties properties = null;
try
{
properties = new Properties();
properties.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
properties.put(Context.PROVIDER_URL, url);
if (user != null)
{
properties.put(Context.SECURITY_PRINCIPAL, user);
properties.put(Context.SECURITY_CREDENTIALS, password == null ? "" : password);
} return new InitialContext(properties);
}
catch(Exception e)
{
System.out.println("Unable to connect to WebLogic server at " + url);
System.out.println("Please make sure that the server is running.");
throw e;
}
}
public HelloHome getHome()
{
return helloHome;
}
public static void main(String[] args)
{
HelloClient client = new HelloClient();
}
}
要不怎么能运行程序啊,
有道理,纸上谈兵没用的
只不过练手嘛,所以就没必要考虑适不适合?达到练手的目的就行!