spring 通过工厂来创建bean

1： 这个例子中我们使用工厂模式来取的bean。首先我们来获取context

public class SpringContextSupport implements ServletContextAware {

    private static Object initObj = null;

    private static int count = 0;

    private static ApplicationContext context;

    public static void init(Object o) {
        initObj = o;
        count++;
    }

    /**
     *
     * gets the instance from the beanId
     *
     * @param object
     * @return void
     */
    public static Object getBean(String beanName) {
        return getApplicationContext().getBean(beanName);
    }

    /**
     *
     * returns applicationContext based on initObj
     *
     * @return ApplicationContext
     */
    public static ApplicationContext getApplicationContext() {
        if (initObj == null) {
            throw new IllegalStateException(
                    "Application context not initialized");
        } else if (initObj instanceof ServletContext) {
            ServletContext servletContext = (ServletContext) initObj;
            return WebApplicationContextUtils
                    .getRequiredWebApplicationContext(servletContext);

        } else if (initObj instanceof String) {
            if (context == null) {
                context = new FileSystemXmlApplicationContext(
                        Constants.FILE_CONTEXT_PATH);
            }
            return context;
        } else {
            throw new IllegalStateException(
                    "You must initialize the context with a String");
        }
    }

    /**
     *
     * initializes servletContext
     *
     * @param context
     * @return void
     */
    public void setServletContext(ServletContext context) {
        init(context);
    }

    public static void initializeStandalone() {
        init("StandAlone");
    }


    /**
*
* initializes servletContext for bid board batch
*
* @param context
* @return void
*/
    public static void initBidBoardBatch() {
        init( Constants.BB_BATCH_STARTUP);
    }
}

备注： String FILE_CONTEXT_PATH = "WEB-INF/conf/user-services.xml";
那么在这个文件中就是我们配置的bean
2: 具体通过工厂是方法来取得我们所需要的bean
public class DAOFactory {
  public UserDAO getUserDAO() throws Exception {
        UserDAO userDAO = null;
        try {
            userDAO = (UserDAO) SpringContextSupport
                    .getBean(DAOConstants.USER_DAO);
        } catch (Exception exception) {
            throw exception;
        }
        return userDAO;
    }
}

3: 那么我们想对应的service工厂模式的创建也类似：如下：
public class CommonServiceFactory {
   public CommonService getCommonService() throws BBSystemException {
        CommonService commonService = null;

        commonService =
                (CommonService) SpringContextSupport
                        .getBean(BBServiceConstants.COMMON_SERVICE);

        if (null == commonService) {
            throw BBUtil.getBBSystemException(BBMessageConstants.OBJECTS_NULL);
        }
        return commonService;
    }
}