Scan similar files in different directories and report differences
There is no reason here for this to be a class. You don't even use any class features and even have to work around it being a class by doing e.g. DirInfo.save(self._dirInfo, fname) instead of being able to do self.save(fname).

I would also add more functions, for example for hashing the file content.

import os
import stat
import hashlib
import json

STAT_FILE = "data.txt"

def get_stat_info(file_name):
    sbuf = os.fstat(os.open(file_name, os.O_RDONLY))
    return {'type': stat.S_IFMT(sbuf.st_mode),
            'mode': stat.S_IMODE(sbuf.st_mode),
            'mtime': sbuf.st_mtime,
            'size': sbuf.st_size}


def hash_file(file_name):
    hasher = hashlib.sha256()
    blocksize = 512000000
    with open(file_name, 'rb') as f:
        for chunk in iter(lambda: f.read(blocksize), b""):
            hasher.update(chunk)
    return hasher.hexdigest()


def probe(dir_name):
    dir_info = {}
    for file in os.listdir(dir_name):
        if file == STAT_FILE:
            continue
        file_with_path = os.path.join(dir_name, file)
        file_info = {'name': file}
        if os.path.isfile(file_with_path):
            file_info.update(get_stat_info(file_with_path))
            file_info['sha256'] = hash_file(file_with_path)
        if os.path.islink(file_with_path):
            file_info['symlink'] = os.readlink(file_with_path)
        dir_info[file] = file_info
    return dir_info


def save(dir_info, file_name):
    with open(file_name, 'w') as f:
        json.dump(dir_info, f)


def load(file_name):
    with open(file_name, 'r') as f:
        return json.load(f)


def compare(dir_info1, dir_info2):
    files1, files2 = dir_info1.keys(), dir_info2.keys()

    for f in files1 - files2:
        print (f, "is verwijderd")
    for f in files2 - files1:
        print (f, "is toegevoegd")
    for f in files1 &amp; files2:
        file_info1, file_info2 = dir_info1[f], dir_info2[f]
        for key in file_info1:
            if file_info1[key] != file_info2[key]:
                print("In bestand:", f, "was", key, file_info1[key], "nu is", key, file_info2[key])


if __name__ == '__main__':
    dir_name1 = "D:\\Testmapje met random files"
    dir_info1 = probe(dir_name1)
    save(dir_info1, os.path.join(dir_name1, STAT_FILE))

    dir_name2 = "D:\\Testmapje met random files 2"
    dir_info2 = probe(dir_name2)
    save(dir_info2, os.path.join(dir_name2, STAT_FILE))

    compare(dir_info1, dir_info2)


Note that the save and load functions are not actually necessary, but I left them in because you might want to look at the results. In the compare function it makes a lot more sense to directly compare the two dictionaries, instead of saving them to a file and reading them back again.

I also changed all variables to conform to Python's official style-guide, PEP8, which recommends lower_case.