使用static方法和从Spring IOC 容器里面取出的方法有什么区别?

public interface CachedLoadService {
     Map<String,Object> loadHomeData();

}

public class CachedUtils {
    private static Date lastSearchTime=null;
    private static Map mapMediaList=null;

    static Object  lock = new Object();

    public static Map  getMediaList() {
        synchronized (lock) { 
            CachedLoadService cachedLoadService=(CachedLoadService) SpringContextUtil.getBean("cachedLoadService"); //或者其它业务类
            try {
                if(lastSearchTime==null) {
                    mapMediaList=cachedLoadService.loadHomeData();
                    lastSearchTime=new Date();
                } else {
                    if(mapMediaList==null) {
                        mapMediaList=cachedLoadService.loadHomeData();
                        lastSearchTime=new Date();
                    } else {
                        mapMediaList=cachedLoadService.loadHomeData();
                        lastSearchTime=new Date();
                    }
                }
                return mapMediaList;
            } catch (Exception e) {
                return mapMediaList;
            }
        }
    }

cachedLoadService.loadHomeData() 就是一个 final static Map ,还有必要去特意弄一个接口吗?这种做法的作用是什么?