《Pro Spring》学习笔记之Spring与JNDI

实验环境：JBoss 5.0 beta2

服务接口：

 

package  Jndi;

public   interface  MessageResolver  ... {
   public String getMessage();
}

四种获取JNDI的实现类：

代码比较简单，不再啰唆了

package  Jndi;

import  javax.naming.Context;
import  javax.naming.NamingException;

import  org.springframework.jndi.JndiCallback;
import  org.springframework.jndi.JndiTemplate;

public   class  JndiCallBackMessageResolver  implements  MessageResolver  ... {

    private String message;
    public String getMessage() ...{
        StringBuffer buffer=new StringBuffer();
        String temp[];
        if(message==null)...{
            temp=lookupMessage();
            for (int i = 0; i < temp.length; i++) ...{
                buffer.append(temp[i]);
            }
        }
        return buffer.toString();
    }
    
    public String[] lookupMessage()...{
        JndiTemplate template=new JndiTemplate();
        String temp[]=new String[]...{};
        String names[]=new String[]...{"java:comp/env/message1","java:comp/env/message2"};
        try ...{
            temp=(String[])template.execute(new BulkLoopupCallback(names));
        } catch (NamingException e) ...{
          System.out.println(e.getMessage());
        }
        return temp;
    }
    
    private class BulkLoopupCallback implements JndiCallback...{
        private String[] names;
        public BulkLoopupCallback(String names[])...{
            this.names=names;
        }
        public Object doInContext(Context ctx) throws NamingException...{
            String messages[]=new String[names.length];
            for (int i = 0; i < names.length; i++) ...{
                messages[i]=(String)ctx.lookup(names[i]);
            }
            return messages;
        }
        
    }

}

 

 

package  Jndi;

public   class  JndiObjectFactoryBeanMessageResolver  implements  MessageResolver  ... {
    private String message;
    public void setMessage(String message) ...{
        this.message = message;
    }
    public String getMessage() ...{
    
        return message;
    }

}

 

 

 

package  Jndi;

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

public   class  TraditionalJNDIMessageResolver  implements  MessageResolver  ... {
    
    private String message;
    public String getMessage() ...{
        if(message==null)...{
            lookupMessage();
        }
        return message;
    }

    public String lookupMessage()...{
        Context ctx;
        try ...{
            ctx = new InitialContext();
            message=(String)ctx.lookup("java:comp/env/message");    
        } catch (NamingException e) ...{
          System.out.println(e.getMessage());
        }
        return message;
    }
}

 

 

package  Jndi;

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

import  org.springframework.jndi.JndiTemplate;

public   class  JndiTemplateMessageResolver   implements  MessageResolver ... {

    private String message;
    public String getMessage() ...{
        if(message==null)...{
            lookupMessage();
        }
        return message;
    }
    
    public String lookupMessage()...{
        JndiTemplate template=new JndiTemplate();
        try ...{
            message=(String)template.lookup("java:comp/env/message");
        } catch (NamingException e) ...{
          System.out.println(e.getMessage());
        }
        return message;
    }

}

 

Servlet

 

package  Jndi;

import  java.io.IOException;
import  java.io.PrintWriter;

import  javax.servlet.ServletException;
import  javax.servlet.http.HttpServlet;
import  javax.servlet.http.HttpServletRequest;
import  javax.servlet.http.HttpServletResponse;

import  org.springframework.context.ApplicationContext;
import  org.springframework.context.support.ClassPathXmlApplicationContext;

public   class  JndiDemoServlet  extends  HttpServlet  ... {

    private ApplicationContext context;
    public JndiDemoServlet() ...{
        super();
    }

    public void destroy() ...{
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{
        String message1=((MessageResolver)context.getBean("traditionalJNDIMessageResolver")).getMessage();
        String message2=((MessageResolver)context.getBean("jndiTemplateMessageResolver")).getMessage();
        String message3=((MessageResolver)context.getBean("jndiObjectFactoryBeanMessageResolver")).getMessage();
        
        String message4=((MessageResolver)context.getBean("jndiCallBackMessageResolver")).getMessage();
        
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <BODY>");
        out.print("jndiTranditional:"+message1+"<br><br>");
        out.print("jndiJndiTemplate:"+message2+"<br><br>");
        out.print("jndiObjectFactory:"+message3+"<br><br>");
        out.print("jndiCallBakc:"+message4+"<br><br>");
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{

         doGet(request,response);
    }

    public void init() throws ServletException ...{
        context=new ClassPathXmlApplicationContext("WEB-INF/applicationContext.xml");
    }

}

 

spring配置文件：

使用JndiObjectFactoryBean的时候，要为resourceRef注入属性true，通知JndiObjectFactoryBean属性是保存在应用程序环境中的，因此如果需要，应该使用java:comp/env的前缀读取JNDI

<? xml version="1.0" encoding="UTF-8" ?>
< beans
     xmlns ="http://www.springframework.org/schema/beans"
    xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd" >
    <!--  传统获取jndi  -->
    < bean  id ="traditionalJNDIMessageResolver"  class ="Jndi.TraditionalJNDIMessageResolver" >
    </ bean >
    <!--  使用jndiTemplate获取jndi  -->
    < bean  id ="jndiTemplateMessageResolver"  class ="Jndi.JndiTemplateMessageResolver" >
    </ bean >
    <!--  使用jndiObjectFactory获取jndi  -->
     < bean  id ="jndiObjectFactoryBeanMessageResolver"  class ="Jndi.JndiObjectFactoryBeanMessageResolver" >
       < property  name ="message" >
         < bean  class ="org.springframework.jndi.JndiObjectFactoryBean" >
           < property  name ="jndiName" >
             < value > message </ value >
           </ property >
           < property  name ="resourceRef" >
             < value > true </ value >
           </ property >
         </ bean >
       </ property >
    </ bean >
    <!--  使用JndiCallBakc  -->
     < bean  id ="jndiCallBackMessageResolver"  class ="Jndi.JndiCallBackMessageResolver" >
    </ bean >
</ beans >

 

web.xml(配置jndi数据)

 

<? xml version="1.0" encoding="UTF-8" ?>
< web-app  version ="2.4"  
    xmlns ="http://java.sun.com/xml/ns/j2ee"  
    xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation ="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
   < servlet >
     < servlet-name > JndiDemoServlet </ servlet-name >
     < servlet-class > Jndi.JndiDemoServlet </ servlet-class >
   </ servlet >

   < servlet-mapping >
     < servlet-name > JndiDemoServlet </ servlet-name >
     < url-pattern > /servlet/JndiDemoServlet </ url-pattern >
   </ servlet-mapping >
   < welcome-file-list >
     < welcome-file > index.jsp </ welcome-file >
   </ welcome-file-list >
  
   < env-entry >
     < env-entry-name > message </ env-entry-name >
     < env-entry-type > java.lang.String </ env-entry-type >
     < env-entry-value > hello world </ env-entry-value >
   </ env-entry >
  
   < env-entry >
     < env-entry-name > message1 </ env-entry-name >
     < env-entry-type > java.lang.String </ env-entry-type >
     < env-entry-value > hello my  </ env-entry-value >
   </ env-entry >
   < env-entry >
     < env-entry-name > message2 </ env-entry-name >
     < env-entry-type > java.lang.String </ env-entry-type >
     < env-entry-value > lovely world </ env-entry-value >
   </ env-entry >
</ web-app >

 

打开浏览器，运行http://localhost:8080/ProSpringStudyWeb/servlet/JndiDemoServlet

结果如下：

jndiTranditional:hello world

jndiJndiTemplate:hello world

jndiObjectFactory:hello world

jndiCallBakc:hello mylovely world