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EJB 的最佳实践：工业强度的 JNDI 优化

豆豆网技术应用频道 2007年07月03日【字号：小中大】收藏本文

关键字： IoC WebSphere Application Server RDF JRuby Spring 2.5 事件处理

内容摘要：在这篇技巧文章中，我们将研究一些最常用的 JNDI 优化。特别地，我们将向您展示如何将高速缓存和通用助手类组合使用，以创建针对 JNDI 开销的工厂风格的解决方案。

package com.ibm.ejb;
import java.util.Map;
import javax.ejb.EJBHome;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class EJBHomeFactory {
private static EJBHomeFactory;
private Map homeInterfaces;
private Context context;
// This is private, and can&acute;t be instantiated directly
private EJBHomeFactory() throws NamingException {
homeInterfaces = new HashMap();
// Get the context for caching purposes
context = new InitialContext();
/**
* In non-J2EE applications, you might need to load up
* a properties file and get this context manually. I&acute;ve
* kept this simple for demonstration purposes.
*/
}
public static EJBHomeFactory getInstance() throws NamingException {
// Not completely thread-safe, but good enough
// (see note in article)
if (instance == null) {
instance = new EJBHomeFactory();
}
return instance;
}
public EJBHome lookup(String jndiName, Class homeInterfaceClass)
throws NamingException {
// See if we already have this interface cached
EJBHome homeInterface = (EJBHome)homeInterfaces.get(homeClass);
// If not, look up with the supplied JNDI name
if (homeInterface == null) {
Object obj = context.lookup(jndiName);
homeInterface =
(EJBHome)PortableRemoteObject.narrow(obj, homeInterfaceClass);
// If this is a new ref, save for caching purposes
homeInterfaces.put(homeInterfaceClass, homeInterface);
}
return homeInterface;
}
}

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