CloudStack采用spring加载bean(cloud-framework-spring-module模块)

CloudStackContextLoaderListener

/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *   http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing,

 * software distributed under the License is distributed on an

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

 * KIND, either express or implied.  See the License for the

 * specific language governing permissions and limitations

 * under the License.

 */

package org.apache.cloudstack.spring.module.web;

import java.io.IOException;

import javax.servlet.ServletContext;

import javax.servlet.ServletContextEvent;

import org.apache.cloudstack.spring.module.factory.CloudStackSpringContext;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.context.ApplicationContext;

import org.springframework.web.context.ConfigurableWebApplicationContext;

import org.springframework.web.context.ContextLoaderListener;

public class CloudStackContextLoaderListener extends ContextLoaderListener {

    public static final String WEB_PARENT_MODULE = "parentModule";

    public static final String WEB_PARENT_MODULE_DEFAULT = "web";

    private static final Logger log = LoggerFactory.getLogger(CloudStackContextLoaderListener.class);

    CloudStackSpringContext cloudStackContext;

    String configuredParentName;

    @Override

    protected ApplicationContext loadParentContext(ServletContext servletContext) {

        return cloudStackContext.getApplicationContextForWeb(configuredParentName);

    }

    @Override

    //上下文初始化，通过servlet内容事件

    public void contextInitialized(ServletContextEvent event) {

        try {

            cloudStackContext = new CloudStackSpringContext();

            event.getServletContext().setAttribute(CloudStackSpringContext.CLOUDSTACK_CONTEXT_SERVLET_KEY, cloudStackContext);

        } catch (IOException e) {

            log.error("Failed to start CloudStack", e);

            throw new RuntimeException("Failed to initialize CloudStack Spring modules", e);

        }

        configuredParentName = event.getServletContext().getInitParameter(WEB_PARENT_MODULE);

        if ( configuredParentName == null ) {

            configuredParentName = WEB_PARENT_MODULE_DEFAULT;

        }

        super.contextInitialized(event);

    }

    @Override

    protected void customizeContext(ServletContext servletContext, ConfigurableWebApplicationContext applicationContext) {

        super.customizeContext(servletContext, applicationContext);

        String[] newLocations = cloudStackContext.getConfigLocationsForWeb(configuredParentName,

                applicationContext.getConfigLocations());

        
　　　　 //设置应用到新的位置

        applicationContext.setConfigLocations(newLocations);

    }

}