Qif to beancount converter. SubTransaction.java https://gist.github.com/tshevchuk/c862b4e77d1bedc3c94776644a6d33a5 , Transaction.java https://gist.github.com/tshevchuk/4f855f96f9bc31c529733e0b7fa4a1ee

QifToBeancount.java

package com.company;

import com.sun.deploy.util.StringUtils;

import java.io.*;
import java.util.*;

public class QifToBeancount {
    public static String convert(String qif) {
        List<Transaction> transactions = new ArrayList<>();
        try {
            parseTransactions(qif, transactions);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return transactionsToBeancount(transactions);
    }

    private static String transactionsToBeancount(List<Transaction> transactions) {
        StringBuilder sb = new StringBuilder();
        for (Transaction tr : transactions) {
            sb.append(tr.getDate())
                    .append(" * \"")
                    .append(tr.getDescription())
                    .append("\"\n  ")
                    .append(tr.getAccount());
            for (SubTransaction subTransaction : tr.getSubTransactions()) {
                sb.append("\n  ")
                        .append(subTransaction.getAccount())
                        .append(" ")
                        .append(invertAmountSign(subTransaction.getAmount()))
                        .append(" UAH");
            }
            sb.append("\n\n");
        }
        return sb.toString();
    }

    private static String invertAmountSign(String amount) {
        if (amount.startsWith("-")) {
            return amount.substring(1);
        } else {
            return "-" + amount;
        }
    }

    private static void parseTransactions(String qif, Collection<Transaction> transactions) throws IOException {
        try (BufferedReader reader = new BufferedReader(new StringReader(qif))) {

            String account = null;
            String date = null;
            String description = null;
            List<SubTransaction> subTransactions = new ArrayList<>();
            String subTransactionAccount = null;

            for (String line; (line = reader.readLine()) != null; ) {
                if ("!Account".equals(line)) {
                    continue;
                } else if (line.charAt(0) == 'N') {
                    account = line.substring(1);
                } else if ("^".equals(line)) {
                    if (date != null) {
                        Transaction transaction = new Transaction();
                        transaction.setDescription(description);
                        transaction.setAccount(account);
                        transaction.setDate(date);
                        transaction.getSubTransactions().addAll(subTransactions);
                        transactions.add(transaction);
                    }
                    date = null;
                    subTransactions.clear();
                    continue;
                } else if ("!Type:Cash".equals(line)) {
                    continue;
                } else if (line.charAt(0) == 'D') {
                    String[] parts = line.substring(1).split("/");
                    if (parts[1].length() < 2) {
                        parts[1] = "0" + parts[1];
                    }
                    if (parts[2].length() < 2) {
                        parts[2] = "0" + parts[2];
                    }
                    date = StringUtils.join(Arrays.asList(parts), "-");
                } else if (line.charAt(0) == 'M') {
                    description = line.substring(1);
                } else if (line.charAt(0) == 'S') {
                    subTransactionAccount = line.substring(1);
                } else if (line.charAt(0) == '$') {
                    String amount = line.substring(1).replace(',', '.');
                    SubTransaction subTransaction = new SubTransaction();
                    subTransaction.setAccount(subTransactionAccount);
                    subTransaction.setAmount(amount);
                    subTransactions.add(subTransaction);
                    subTransactionAccount = null;
                } else {
                    System.out.println("ERROR!!!");
                }
            }
        }
    }
}