我的監聽器代碼如下package org.javaimplant.newsfeed.Init;import javax.naming.Context;import javax.naming.InitialContext;import javax.naming.NameClassPair;import javax.naming.NamingEnumeration;import javax.servlet.ServletContext;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import javax.sql.DataSource;import org.apache.log4j.Logger;import org.javaimplant.newsfeed.Servlets.DataSourceServlet;import org.javaimplant.newsfeed.data.DataAccessObject;public class Init implements ServletContextListener {    private Logger logger=Logger.getLogger(this.getClass());    public void contextInitialized(ServletContextEvent sce)     {        ServletContext servletContext = sce.getServletContext();        try {        contextInitialized2(servletContext);        }        catch (Exception e)        {        logger.error("Initialization failed.", e);        throw new RuntimeException(e);        }        logger.debug("Initialization succeeded.");      }    private void contextInitialized2(ServletContext servletContext)    throws Exception     {        InitialContext enc = new InitialContext();        NamingEnumeration<NameClassPair> list = enc.list("java:comp/env/datasource");        while (list.hasMore())        {          System.out.println(list.next().getName());        }        Context compContext = (Context) enc.lookup("java:comp/env");        DataSource dataSource = (DataSource) compContext.lookup("datasource");//      DataAccessObject.setDatasource(dataSource);        DataSourceServlet.setDataSource(dataSource);    }    public void contextDestroyed(ServletContextEvent sce) {        // TODO Auto-generated method stub    }}運行代碼時出現以下錯誤。我不知道為什么我的應用程序無法從 xml 文件中讀取上下文。請幫忙javax.naming.NamingException：名稱未綁定到 org.javaimplant.newsfeed.Init.Init.contextInitialized(Init.java:29) 處的上下文