Search code examples
javabinaryfilesmainframeebcdic

How to convert mainframe binary file to readable form

We are receiving EBCDIC mainframe file over XCOM in binary format. Currently, there's a legacy C-based application which is converting it to readable ASCII format. This is how the file looks like now:

enter image description here

As the part of migration, we have to migrate the legacy application on Java. Can you please suggest or share some link how to convert that binary file to readable format in Java?

Solution

  • EBCDIC - like ASCII or Latin-1 - is text. You can try one of "Cp037", "Cp500", "Cp1047". As there are more than one EBCDIC variant check Wikipedia or such. Unfortunately not every Charset is provided by the Java SE. See Convert String from ASCII to EBCDIC in Java?

    Since java 11 you can use Files.readString/writeString, otherwise one needs to use Files.readAllBytes.

    Path ebcdicPath = Paths.get("...");
Path utf8Path = ebcdicPath.resolveSibling("utf8.txt");
Charset ebcdic = Charset.forName("Cp1047");
String content = Files.readString(ebcdicPath, ebcdic);
Files.writeString(utf8Path, content, StandardCharsets.UTF_8);

    You might get problems with the line endings, as in Unicode the EBCDIC originating NEL (U+0085) is a legal newline/carriage return. Using Files.lines would string line endings.

    Code for a hex dump of some bytes:

    Path path = Paths.get("...");
byte[] content = Files.readAllBytes(path);
for (int i = 0; i < 16; ++i) {
    System.out.printf(" %02x", content[i] & 0xFF);
}
System.out.println();

        byte[] c = {(byte)0xf0, (byte)0xf0, (byte)0xf0, (byte)0xf0, (byte)0xf0, (byte)0xf9, (byte)0xf7, (byte)0xf7,
            (byte)0xf1, (byte)0xf2, (byte)0xf2, (byte)0xf0, (byte)0xf3, (byte)0xf2, (byte)0xf1, (byte)0xf0};
    Charset ebcdic = Charset.forName("Cp1047");
    System.out.println(new String(c, ebcdic));

0000097712203210