객체 리스트 파일로 쓰기 - 테스트 데이터를 할 일이 있어서 좀.. 음.

참고 
https://qkrrudtjr954.github.io/java/2017/11/13/file-write.html
http://woowabros.github.io/experience/2017/10/17/java-serialize.html


@Test
public void objectStreamTest() throws Exception{
    List<?> timeInfoList = repository.findAllByOrderByDateTimeAsc();

    byte[] serializedMember;
    try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
        try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
            oos.writeObject(timeInfoList);
            // serializedMember -> 직렬화된 member 객체
            serializedMember = baos.toByteArray();
        }
    }
    // 바이트 배열로 생성된 직렬화 데이터를 base64로 변환
    String s = Base64.getEncoder().encodeToString(serializedMember);
    System.out.println(s);

    serializedMember = Base64.getDecoder().decode(s);
    try (ByteArrayInputStream bais = new ByteArrayInputStream(serializedMember)) {
        try (ObjectInputStream ois = new ObjectInputStream(bais)) {
            // 역직렬화된 Member 객체를 읽어온다.
            Object objectMember = ois.readObject();
            List<StockTimeInfo> stockTimeInfos = (List<StockTimeInfo>) objectMember;
            System.out.println(stockTimeInfos);
        }
    }

    try (FileWriter fw = new FileWriter(new File("filename.data"));
         BufferedWriter bw = new BufferedWriter(fw)) {
        bw.write(s);
    }
}