public String getActualContextKey() {
        // String dbkey = DB_KEY.get();
        String dbkey = ThreadContext.getContext(dbName);
        log.debug("get data source Key[" + dbkey + "]");
        return dbkey;
    }
public String getActualContextKey ( ) { String dbkey = ThreadContext . getContext ( dbName ) ; log . debug ( "get data source Key[" + dbkey + "]" ) ; return dbkey ; }
获得当前dataSourceContext中实际保存的数据源key,没有就返回null