java获取spring的bean

/**
 * 载入spring配置文件，提供getBean接口.
 * @author xiongzy
 *
 */
public final class BeanLocator {
    private static final Logger logger = Logger.getLogger(BeanLocator.class);
    /**
     * 单实例.
     */
    private static BeanLocator instance = null;
    
    /**
     * 缺省配置文件名.
     */
    private static final String DEFAULT_CONFIGURATION_FILENAME = "spring/applicationContext.xml";
    
    /**
     * 载入配置文件名称.
     */
    private static String configurationFileName = null;
    
    /**
     * spring环境.
     */
    private ApplicationContext applicationContext = null;

    /**
     * 单例模式.
     * @return 接口
     */
    public static BeanLocator getInstance() {
        if (instance == null) {
            // 同步控制代码, 防止初始化多次.
            synchronized(logger) {
                if (instance == null) {
                    instance = new BeanLocator();
                }
            }
        }
        return instance;
    }

    /**
     * 设置配置文件名称.
     * @param fileName 配置文件名称
     */
    public static void setConfigurationFileName(String fileName) {
        configurationFileName = fileName;
    }

    
    /**
     * 私有构造.
     */
    private BeanLocator() {
        if (configurationFileName == null || configurationFileName.length() == 0) {
            configurationFileName = DEFAULT_CONFIGURATION_FILENAME;
        }
        // 得到spring框架bean环境
        try{
            applicationContext = new ClassPathXmlApplicationContext(configurationFileName);
        }catch(Exception e){
            logger.error("初始化spring配置文件时发生异常:" + e.getMessage(), e);
            throw new RuntimeException("初始化spring配置文件时发生异常:" + e.getMessage(), e);
        }
    }

    /**
     * spring getBean 接口.
     * @param beanName 接口名称
     * @return 接口
     */
    public Object getBean(String beanName) {
        return applicationContext.getBean(beanName);

    }

    public static void main(String[] args) {
        CityInfoService cityInfoService = (CityInfoService)BeanLocator.getInstance().getBean("cityInfoService");
        System.out.println(cityInfoService);
    }

}