用于cobol显示和解包数字字段的Java映射

首先,有来自IBM& Legstar 从Cobol Copybooks生成Java类。我自己的套餐 JRecord 也可以使用,但它面向文件而不是在线处理。

基本上,字段的最后一个字符包含符号+数字。我猜数据来自主机;因此,对于美国-Ebcdic(CP037/IBM237),最后一位数字将是

          0 1 2 3 4 5 6 7 8 9
positive  { A B C D E F G H I
negative  } J K L M N O P Q R 

因此,对于+123,它将是00000012C(C=+3),-123将是00000012 L。

更糟糕的是,在不同的EBCIDIC方言和ASCII中,+0和-0是不同的。因此,您要么需要确切地知道使用的是Ebcidic的哪个版本,要么需要在字节级别进行转换。

这个 来自分区 中的方法 JRecord Conversion 转换是否:

    private static int positiveDiff = 'A' - '1';
    private static int negativeDiff = 'J' - '1';

    private static char positive0EbcdicZoned = '{';
    private static char negative0EbcdicZoned = '}';

    public static String fromZoned(String numZoned) {
        String ret;
        String sign = "";
        char lastChar, ucLastChar;

        if (numZoned == null || ((ret = numZoned.trim()).length() == 0) || ret.equals("-")) {
            return "";
        }

        lastChar = ret.charAt(ret.length() - 1);
        ucLastChar = Character.toUpperCase(lastChar);


        switch (ucLastChar) {
        case 'A': case 'B': case 'C': 
            case 'D': case 'E': case 'F':
            case 'G': case 'H': case 'I':
            lastChar = (char) (ucLastChar - positiveDiff);
            break;
        case 'J': case 'K': case 'L':
        case 'M': case 'N': case 'O':
        case 'P': case 'Q': case 'R':
            sign = "-";
            lastChar = (char) (ucLastChar - negativeDiff);
            break;
        default:
            if (lastChar == positive0EbcdicZoned) {
                lastChar = '0';
            } else if (lastChar == negative0EbcdicZoned) {
                lastChar = '0';
                sign = "-";
            }           
        }
        ret = sign + ret.substring(0, ret.length() - 1) + lastChar;

         return ret;
    }

但在字节级别更容易实现,应该如下所示(代码未经测试):

    private static final byte HIGH_NYBLE = (byte) 0xf0;
    private static final byte LOW_NYBLE  = (byte) 0x0f;
    private static final byte ZONED_POSITIVE_NYBLE_OR = (byte) 0xCF;
    private static final byte ZONED_NEGATIVE_NYBLE_OR = (byte) 0xDF;
    private static final byte ZONED_NEGATIVE_NYBLE_VALUE = (byte) 0xD0;                        

    signByte = bytes[bytes.length - 1];

    negative = false;
    if (((byte) (signByte & HIGH_NYBLE)) == ZONED_NEGATIVE_NYBLE_VALUE) {
        negative = true;
    }

    long result = 0;
    for (int i = 0; i < bytes.length; i++) {
        result = result * 10 + (bytes[i] & LOW_NYBLE);
    }

    if (negative) {
       result = -1 * result;
    }