Creates a new INSERT line for a Flyway SQL migration. Useful for patching migration information in the schema_version table (I won't judge, don't worry). Parts of this code were extracted from Flyway v6.1.4.

CalculateFlywayChecksum.java

import java.io.BufferedReader;
import java.io.FileReader;
import java.nio.charset.StandardCharsets;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;
import java.util.zip.CRC32;

public class CalculateFlywayChecksum {

	public static void main(String[] args) throws Exception {
		String tableName = "schema_version";

		if (args.length < 1) {
			System.err.println("Missing next installed_rank ID.");
			System.exit(1);
		}

		if (args.length < 2) {
			System.err.println("Missing input filename for the migration script.");
			System.exit(1);
		}

		if (args.length > 2) {
			tableName = args[2];
		}

		long installedRank = Long.parseLong(args[0]);
		String filename = args[1];
		int checksum = calculateChecksum(filename);
		String description = filename.replaceAll("^.+?__", "").replaceAll(".[sS][qQ][lL]$", "").replace("_", " ");
		String version = filename.replaceAll("^\\w", "").replaceAll("__.+$", "").replaceAll("_", ".");
		String type = "SQL";
		String installedBy = "admin";
		String installedOn = DateTimeFormatter.ofPattern("YYYY-MM-dd hh:mm:ss").format(LocalDateTime.now());
		String executionTime = "0";
		String success = "true";

		System.out.println(String.format(
			"INSERT INTO %s (" +
				"installed_rank, " +
				"version, " +
				"description, " +
				"type, " +
				"script, " +
				"checksum, " +
				"installed_by, " +
				"installed_on, " +
				"execution_time, " +
				"success" +
				") values (%d, '%s', '%s', '%s', '%s', %d, '%s', '%s', %s, %s);",
			tableName,
			installedRank,
			version,
			description,
			type,
			filename,
			checksum,
			installedBy,
			installedOn,
			executionTime,
			success
		));
	}

    public static final int calculateChecksum(String filename) throws Exception {
		final CRC32 crc32 = new CRC32();

		try (
			FileReader file = new FileReader(filename);
			BufferedReader reader = new BufferedReader(file, 4096)
		) {
			String line = reader.readLine();

			if (line != null) {
				line = filterBomFromString(line);

				do {
					//noinspection Since15
					crc32.update(trimLineBreak(line).getBytes(StandardCharsets.UTF_8));
				} while ((line = reader.readLine()) != null);
			}
		}

		return (int) crc32.getValue();
    }

	public static String trimLineBreak(String str) {
		if (!hasLength(str)) {
			return str;
		}
		StringBuilder buf = new StringBuilder(str);
		while (buf.length() > 0 && isLineBreakCharacter(buf.charAt(buf.length() - 1))) {
			buf.deleteCharAt(buf.length() - 1);
		}
		return buf.toString();
	}

	private static boolean isLineBreakCharacter(char ch) {
		return '\n' == ch || '\r' == ch;
	}

	public static boolean hasLength(String str) {
		return str != null && str.length() > 0;
	}

	private static final char BOM = '\ufeff';

	public static boolean isBom(char c) {
		return c == BOM;
	}

	public static String filterBomFromString(String s) {
		if (s.isEmpty()) {
			return s;
		}

		if (isBom(s.charAt(0))) {
			return s.substring(1);
		}

		return s;
	}
}