public static String getAppConnClassName(String appConnName, String libPath,
                                             ClassLoader classLoader) throws NoSuchAppConnException, IOException {
        //1.Get all the jar packages under the directory
        List<String> jars = getJarsOfPath(libPath);
        //2.Get the subclass of appconn from all jars
        for (String jar : jars) {
            for (String clazzName : getClassNameFrom(jar)) {
                //3.Then find the subclass of appconn in the corresponding jar package
                if (isChildClass(clazzName, AppConn.class, classLoader)) {
                    return clazzName;
                }
            }
        }
        throw new NoSuchAppConnException("Cannot find a appConn instance for AppConn " + appConnName + " in lib path " + libPath);
    }
Obtain the fully qualified name of the appconn to be instantiated.
dss-appconn/dss-appconn-loader/src/main/java/com/webank/wedatasphere/dss/appconn/loader/utils/AppConnUtils.java