99精品在线直播,久草在线免费福利资源,亚洲综合电影

Context解释

KanIT — Mon, 14 Aug 2006 07:03:00 GMT

下文�Q�Context�Q�这个术语，在我们日常的开发工作中�l�常被提及�?

那么怎么理解context呢，或者说什么是context呢？下面��׃��我个人的角度来进行解�?/p>

刚刚接触context�q�个词好像还是在看《J2EE技术内�q�》那本书的时候，那个时候对于上下文的理解基本上��是0�Q�只知道�q�个词而已�?/p>

如今对于context�q�个词，则有了种恍然大悟的感觉。中文翻译�v来就是“上下文”，从字面意思我们就可以很清楚的�ȝ��解�?/p>

首先“上下”表现的是一�U�承上启下的关系�Q�是一�U�从前一个事物传递给后一个事物的�q�么个东�ѝ��用面向对象语言来说�Q�就是从一个object传递到另外一个object的消息而已�Q�只不过�q�个message里面包含了一些公用的信息�?/p>

其次�Q�“文”意味着�q�是一�U�信息，一�l�文字，一些内宏V��也��是说他含有了其他事物所需要的信息�?/p>

KanIT 2006-08-14 15:03 发表评论

Eclipse+MyEclipse+weblogic8开发EJB初探

KanIT — Wed, 09 Aug 2006 03:18:00 GMT

一、无状态会话BEAN
搞了几年JAVA�?最�q�由于完全不懂EJB技�?被取�W�了!我怒而学�?
以下��׃��留的代码,大部分抄袭网上的,只�ؓ自己保留,望看客一�W�而过!
关键字一:DOMAIN�?br />为WEBLOGIC��理应用的机�?用WEBLOGIC自带的Configuration Wizard工具生成,�Ҏ��功能不同能创��Z��同的工作�?
关键字二:部��v
Eclipse+MyEclipse提供了比较强大的部��v功能,�q�里忽略�?
具体代码如下:
package com.ejb;

import java.rmi.RemoteException;

import javax.ejb.EJBException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;

/**
* XDoclet-based session bean. The class must be declared
* public according to the EJB specification.
*
* To generate the EJB related files to this EJB:
*  - Add Standard EJB module to XDoclet project properties
*  - Customize XDoclet configuration for your appserver
*  - Run XDoclet
*
* Below are the xdoclet-related tags needed for this EJB.
*
* @ejb.bean name="HelloWorld"
*           display-name="Name for HelloWorld"
*           description="Description for HelloWorld"
*           jndi-name="ejb/HelloWorld"
*           type="Stateless"
*           view-type="remote"
*/
public class HelloWorld implements SessionBean {

/** The session context */
private SessionContext context;
private String message = "helloworld!";
public HelloWorld() {
// TODO Auto-generated constructor stub
}

public void ejbActivate() throws EJBException, RemoteException {
// TODO Auto-generated method stub

}

public void ejbPassivate() throws EJBException, RemoteException {
// TODO Auto-generated method stub

}

public void ejbRemove() throws EJBException, RemoteException {
// TODO Auto-generated method stub

}

/**
* Set the associated session context. The container calls this method
* after the instance creation.
*
* The enterprise bean instance should store the reference to the context
* object in an instance variable.
*
* This method is called with no transaction context.
*
* @throws EJBException Thrown if method fails due to system-level error.
*/
public void setSessionContext(SessionContext newContext)
throws EJBException {
context = newContext;
}

/**
* 自己新创建的业务�Ҏ��
**/
public String getMessage()throws EJBException
{
return this.message;
//return new String("helloworld!");
}
///////////////////////////////////////////////////////////////////////////////////分割�U?//////////////////////////////////////////////////////////////////////////
/*
* Generated by XDoclet - Do not edit!
*/
package com.ejb;

/**
* Session layer for HelloWorld.
* @xdoclet-generated at ${TODAY}
* @copyright The XDoclet Team
* @author XDoclet
* @version ${version}
*/
public class HelloWorldSession
   extends com.ejb.HelloWorld
   implements javax.ejb.SessionBean
{
   public void ejbActivate() throws javax.ejb.EJBException, java.rmi.RemoteException
   {

super.ejbActivate();
}

   public void ejbPassivate() throws javax.ejb.EJBException, java.rmi.RemoteException
   {
      super.ejbPassivate();
   }

   public void setSessionContext(javax.ejb.SessionContext ctx) throws javax.ejb.EJBException
   {
      super.setSessionContext(ctx);
   }

   public void unsetSessionContext()
   {
   }

   public void ejbRemove() throws javax.ejb.EJBException, java.rmi.RemoteException
   {
      super.ejbRemove();
   }

   public void ejbCreate() throws javax.ejb.CreateException
   {
   }
}
//////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////

/*
* Generated by XDoclet - Do not edit!
*/
package com.interfaces;

import javax.ejb.EJBException;
import java.rmi.*;

/**
* Remote interface for HelloWorld.
* @xdoclet-generated at ${TODAY}
* @copyright The XDoclet Team
* @author XDoclet
* @version ${version}
*/
public interface HelloWorld
   extends javax.ejb.EJBObject
{
   /**
    * An example business method
    * @throws EJBException Thrown if method fails due to system-level error.    */
   /*public void replaceWithRealBusinessMethod( )
      throws java.rmi.RemoteException;*/
   public String getMessage()throws EJBException,RemoteException;
}
//////////////////////////////////////////////////////////////////////////////分割�U?////////////////////////////////////////////////////////////////////////////
/*
* Generated by XDoclet - Do not edit!
*/
package com.interfaces;

/**
* Home interface for HelloWorld.
* @xdoclet-generated at ${TODAY}
* @copyright The XDoclet Team
* @author XDoclet
* @version ${version}
*/
public interface HelloWorldHome
   extends javax.ejb.EJBHome
{
   public static final String COMP_NAME="java:comp/env/ejb/HelloWorld";
   public static final String JNDI_NAME="ejb/HelloWorld";

public com.interfaces.HelloWorld create()
throws javax.ejb.CreateException,java.rmi.RemoteException;

}
/////////////////////////////////////////////////////////////////////////////分割�U?////////////////////////////////////////////////////////////////////////////
/*
* Generated file - Do not edit!
*/
package com.interfaces;

/**
* Utility class for HelloWorld.
* @xdoclet-generated at ${TODAY}
* @copyright The XDoclet Team
* @author XDoclet
* @version ${version}
*/
public class HelloWorldUtil
{
/** Cached remote home (EJBHome). Uses lazy loading to obtain its value (loaded by getHome() methods). */
private static com.interfaces.HelloWorldHome cachedRemoteHome = null;

   private static Object lookupHome(java.util.Hashtable environment, String jndiName, Class narrowTo) throws javax.naming.NamingException {
      // Obtain initial context
      javax.naming.InitialContext initialContext = new javax.naming.InitialContext(environment);
      try {
         Object objRef = initialContext.lookup(jndiName);
         // only narrow if necessary
         if (java.rmi.Remote.class.isAssignableFrom(narrowTo))
            return javax.rmi.PortableRemoteObject.narrow(objRef, narrowTo);
         else
            return objRef;
      } finally {
         initialContext.close();
      }
   }

// Home interface lookup methods

   /**
    * Obtain remote home interface from default initial context
    * @return Home interface for HelloWorld. Lookup using COMP_NAME
    */
   public static com.interfaces.HelloWorldHome getHome() throws javax.naming.NamingException
   {
      if (cachedRemoteHome == null) {
            cachedRemoteHome = (com.interfaces.HelloWorldHome) lookupHome(null, com.interfaces.HelloWorldHome.COMP_NAME, com.interfaces.HelloWorldHome.class);
      }
      return cachedRemoteHome;
   }

   /**
    * Obtain remote home interface from parameterised initial context
    * @param environment Parameters to use for creating initial context
    * @return Home interface for HelloWorld. Lookup using COMP_NAME
    */
   public static com.interfaces.HelloWorldHome getHome( java.util.Hashtable environment ) throws javax.naming.NamingException
   {
       return (com.interfaces.HelloWorldHome) lookupHome(environment, com.interfaces.HelloWorldHome.COMP_NAME, com.interfaces.HelloWorldHome.class);
   }

/** Cached per JVM server IP. */
private static String hexServerIP = null;

// initialise the secure random instance
private static final java.security.SecureRandom seeder = new java.security.SecureRandom();

   /**
    * A 32 byte GUID generator (Globally Unique ID). These artificial keys SHOULD NOT be seen by the user,
    * not even touched by the DBA but with very rare exceptions, just manipulated by the database and the programs.
    *
    * Usage: Add an id field (type java.lang.String) to your EJB, and add setId(XXXUtil.generateGUID(this)); to the ejbCreate method.
    */
   public static final String generateGUID(Object o) {
       StringBuffer tmpBuffer = new StringBuffer(16);
       if (hexServerIP == null) {
           java.net.InetAddress localInetAddress = null;
           try {
               // get the inet address

               localInetAddress = java.net.InetAddress.getLocalHost();
           }
           catch (java.net.UnknownHostException uhe) {
               System.err.println("HelloWorldUtil: Could not get the local IP address using InetAddress.getLocalHost()!");
               // todo: find better way to get around this...
               uhe.printStackTrace();
               return null;
           }
           byte serverIP[] = localInetAddress.getAddress();
           hexServerIP = hexFormat(getInt(serverIP), 8);
       }

       String hashcode = hexFormat(System.identityHashCode(o), 8);
       tmpBuffer.append(hexServerIP);
       tmpBuffer.append(hashcode);

       long timeNow      = System.currentTimeMillis();
       int timeLow       = (int)timeNow & 0xFFFFFFFF;
       int node          = seeder.nextInt();

       StringBuffer guid = new StringBuffer(32);
       guid.append(hexFormat(timeLow, 8));
       guid.append(tmpBuffer.toString());
       guid.append(hexFormat(node, 8));
       return guid.toString();
   }

   private static int getInt(byte bytes[]) {
       int i = 0;
       int j = 24;
       for (int k = 0; j >= 0; k++) {
           int l = bytes[k] & 0xff;
           i += l << j;
           j -= 8;
       }
       return i;
   }

   private static String hexFormat(int i, int j) {
       String s = Integer.toHexString(i);
       return padHex(s, j) + s;
   }

   private static String padHex(String s, int i) {
       StringBuffer tmpBuffer = new StringBuffer();
       if (s.length() < i) {
           for (int j = 0; j < i - s.length(); j++) {
               tmpBuffer.append('0');
           }
       }
       return tmpBuffer.toString();
   }
}
////////////////////////////////////////////////////////////////////////////////////////分割�U?//////////////////////////////////////////////////////////////////
配置文�g如下�Q?br />ejb-jar.xml

Generated by XDoclet

         Name for HelloWorld

HelloWorld

         com.interfaces.HelloWorldHome
         com.interfaces.HelloWorld
         com.ejb.HelloWorldSession
         Stateless
         Container

//////////////////////////////////////////////////////////////////////////////分割�U?//////////////////////////////////////////////////////////////////////////
weblogic-ejb-jar.xml

      HelloWorld

ejb/HelloWorld

////////////////////////////////////////////////////////////////////////分割�U?//////////////////////////////////////////////////////////////////////////////////
打成JIA包部�|�到WEBLOGIC服务器�?br />最后是调用代码�Q?br />package com;

import java.rmi.RemoteException;
import java.util.Properties;

import javax.ejb.CreateException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;

import com.interfaces.HelloWorld;
import com.interfaces.HelloWorldHome;
import javax.rmi.PortableRemoteObject;

public class EJBTest {

     /**
      * @param args
     */
     public static void main(String[] args) throws Exception {
         // TODO 自动生成�Ҏ��存根
         Properties properties=new Properties();
         properties.setProperty(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
         properties.setProperty(Context.PROVIDER_URL,"t3://localhost:7001");

         Context context;
         try {
             context = new InitialContext(properties);
             HelloWorldHome hwh=(HelloWorldHome)context.lookup("ejb/HelloWorld");
             HelloWorld hw=hwh.create();
             String s=hw.getMessage();
             System.out.println(s);
         } catch (NamingException e) {
             // TODO 自动生成 catch �?br />             e.printStackTrace();
         } catch (RemoteException e) {
             // TODO 自动生成 catch �?br />             e.printStackTrace();
         } catch (CreateException e) {
             // TODO 自动生成 catch �?br />             e.printStackTrace();
         }
    /*Properties properties=new Properties();
         properties.setProperty(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
         properties.setProperty(Context.PROVIDER_URL,"t3://localhost:7001");
    Context context = new InitialContext(properties);
    Object obj = context.lookup("ejb/HelloWorld");
    HelloWorldHome home = (HelloWorldHome)PortableRemoteObject.narrow(obj,HelloWorldHome.class );
    HelloWorld hello = home.create();
    System.out.println(hello.getMessage());*/
     }
}

部��vEJB

1. MyEclipse >Add and Remove Project Deployments

2. 点击 add �Q�添加部�|�服务器 weblogic �?br />
虽然能��用了�Q�但�q�是有很多地方不太明白。慢慢进步咯�Q?/p>

KanIT 2006-08-09 11:18 发表评论

KanIT — Mon, 31 Jul 2006 03:22:00 GMT

看过三国志的朋友都知道一句名�a�:万事具备,只欠东风.
最�q�在学习SPRING框架的时候对此又有了深层的理�?
最�q�开发一个几百�h的大��目,�׃��某些因素,不能使用开源框�?我们开发�h员商�?准备��应潮流,使用SPRING框架的某些设计思想来完成工�?
�׃��大家都没有几百�h一起工作的��目�l�验,所以开始阶�D�|��痛苦而没有成效的.特别在商议相互调用的接口�?��直成了讨仯��L��菜市�?每个人的��x��,水��^,及设计能力的差异).~_~!!!
百无聊赖�?跑去开三国(你们吵你们的�?我休息先),看到诸葛亮借东风一�?�H�然灉|��一�?�q�不��是SPRING框架的IOC思想�??我先万事具备再说,只欠东风��OK!惛_��q�里,心中�H�喜,于是��需要的接口数据整理出来写了个XML文档,�q�用DTD定义,直接扔给调用我的家伙,想用我的接口�??我就要这些数�?你看着办吧~~!
于是不管他��求的表情,自己工作��M��.那个心里爽啊~
下面是一些模拟代�?希望能有�?
/*定义依赖注入的数据接�?/
public interface IOCINTERFACE
{
   //只定义一个验证方�?验证DTD定义的数�?br />   public boolean validate();
}
////////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////////////////////
/**/
class IOCObject implement IOCINTERFACE
{
   //需要注入的数据
   private String username;
   public void setUsername(String username)
   {
      this.username = username;
   }
   public String getUsername()
   {
      return this.username ;
   }
   //验证一下是否是我要的数�?br />   public boolean validate()
   {
      if(this.username = null)
      {
         return false;
      }
      return true;
   }
}
////////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////////////////////
/*再定义一个执行接�?/
public interface OPERATION
{
   public void execute();
}
////////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////////////////////
class Test implement OPERATION
{
   //定义操作对象
   private IOCObject obj;
   public void Test( IOCObject obj)
   {
      this.obj = obj;
   }
   public void execute()
   {
      if(this.obj.validate)
      {
         //处理业务逻辑
         System.out.println(this.obj.getUsername+"hello!");
      }
      else
      {
         //异常日志
            System.out.println("MB~~~�l�的什么数据啊~~我叼!")
      }
   }
}
////////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////////////////////
/*万事具备�?借东风吧!*/
public class Main
{
   public static void main(String[]args)
   {
      //做个东风�?br />      IOCObject obj = new IOCObject ();
      obj .setUsername("KenIT");
      //依赖注入�?高兴�?
      Test test = new Test(ob);
      //完成工作,打完收功
      test.execute();
   }
}
////////////////////////////////////////////////////////////////////////////////分割�U?///////////////////////////////////////////////////////////////////////////////////////
回想来发现IOC��是我们的诸葛老前辈发明的,居然.....,我强烈呼吁收版权�E?
中华民族万岁~~~!

KanIT 2006-07-31 11:22 发表评论