用Java解压缩COMP-3数据（嵌入Pentaho） [英] COMP-3 data unpacking in Java (Embedded in Pentaho)

问题描述

我们在阅读Pentaho ETL中嵌入的Java中的COMP-3数据时遇到了挑战。在平面文件中存在少量Float值作为压缩小数存储以及其他纯文本。虽然普通文本正在被正确阅读，但我们尝试使用 Charset.forName（CP500）; ，但它从未奏效。我们仍然得到垃圾字符。

We are facing a challenge in reading the COMP-3 data in Java embedded inside Pentaho ETL. There are few Float values stored as packed decimals in a flat file along with other plain text. While the plain texts are getting read properly, we tried using Charset.forName("CP500");, but it never worked. We still get junk characters.

由于Pentaho脚本不支持COMP-3，因此在他们的论坛中他们建议使用用户定义的Java类。如果你碰到并解决了这个问题，有没有人可以帮助我们？

Since Pentaho scripts doesn't support COMP-3, in their forums they suggested to go with User Defined Java class. Could anyone help us if you have come across and solved such?

推荐答案

这是一个Cobol文件???，你有吗？ Cobol Copybook ???
可能的选项包括

Is it a Cobol File ???, Do you have a Cobol Copybook ???. Possible options include

1. 正如Bill所说，将Comp-3转换为源机器上的文本


2. 编写您自己的转换代码


3. 使用像 JRecord这样的库。 注意：我是JRecord的作者

1. As Bill said Convert the Comp-3 to Text on the source machine
2. Write your own Conversion Code
3. Use a library like JRecord. Note: I am the author of JRecord

---

转换Comp-3

in Comp-3，

---

Converting Comp-3

in Comp-3,

Value    Comp-3 (signed)   Comp-3 (Unsigned)   Zoned-Decimal
 123     x'123c'           x'123f' ??            "12C"
-123     x'123d'                                 "12L" 

不止一个将comp-3转换为十进制整数的方法。单程
是

There is more than one way to convert a comp-3 to a decimal integer. One way is to

1. Connvert x'123c' - >> String123c


2. 删除最后一个字符并测试符号

转换comp3的Java代码（来自字节数组：

Java Code to convert comp3 (from a byte array:

        public static String getMainframePackedDecimal(final byte[] record,
                                               final int start,
                                               final int len) {  

            String hex  = getDecimal(record, start, start + len);
                //Long.toHexString(toBigInt(start, len).longValue());
            String ret  = "";
            String sign = "";

            if (! "".equals(hex)) {
                switch (hex.substring(hex.length() - 1).toLowerCase().charAt(0)) {
                    case 'd' : sign = "-";
                        case 'a' :
                        case 'b' :
                        case 'c' :
                        case 'e' :
                        case 'f' :
                            ret = sign + hex.substring(0, hex.length() - 1);
                        break;
                        default:
                            ret = hex;
                }
            }

            if ("".equals(ret)) {
                ret = "0";
            }
        }

        public static String getDecimal(final byte[] record, final int start, final int fin) {
            int i;
            String s;
            StringBuffer ret = new StringBuffer("");
            int b;

            for (i = start; i < fin; i++) {
                b = toPostiveByte(record[i]);
                s = Integer.toHexString(b);
                if (s.length() == 1) {
                    ret.append('0');
                }
                ret.append(s);

            }

            return ret.toString();
        }

---

JRecord

在 JRecord 中，如果您有Cobol Copybook，
有

---

JRecord

In JRecord, if you have a Cobol Copybook, there is

• Cobol2Csv 使用Cobol Copybook将Cobol-Data文件转换为CSV的程序


• Data2Xml 使用Cobol Copybook将Cobol数据文件转换为Xml。


• 阅读带有Cobol Copybook的Cobol数据文件。


• 读取带有Xml的固定宽度文件描述


• 用Java定义字段

• Cobol2Csv a program to convert a Cobol-Data file to CSV using a Cobol Copybook
• Data2Xml convert a Cobol Data file to Xml using a Cobol Copybook.
• Read Cobol-Data File with a Cobol Copybook.
• Read a Fixed width file with a Xml Description
• Define the Fields in Java

        ICobolIOBuilder ioBldr = JRecordInterface1.COBOL
                .newIOBuilder(copybookName)
                    .setDialect( ICopybookDialects.FMT_MAINFRAME)
                    .setFont("cp037")
                    .setFileOrganization(Constants.IO_FIXED_LENGTH)
                .setDropCopybookNameFromFields(true);
        AbstractLine saleRecord;

        AbstractLineReader reader  = ioBldr.newReader(salesFile);
        while ((saleRecord = reader.read()) != null) {
            ....
        }

        reader.close();

使用JRecord在Java中定义文件

Defining the File in Java with JRecord

        AbstractLineReader reader = JRecordInterface1.FIXED_WIDTH.newIOBuilder()
                                .defineFieldsByLength()
                                    .addFieldByLength("Sku"  , Type.ftChar,   8, 0)
                                    .addFieldByLength("Store", Type.ftNumRightJustified, 3, 0)
                                    .addFieldByLength("Date" , Type.ftNumRightJustified, 6, 0)
                                    .addFieldByLength("Dept" , Type.ftNumRightJustified, 3, 0)
                                    .addFieldByLength("Qty"  , Type.ftNumRightJustified, 2, 0)
                                    .addFieldByLength("Price", Type.ftNumRightJustified, 6, 2)
                                .endOfRecord()
                                .newReader(this.getClass().getResource("DTAR020_tst1.bin.txt").getFile());
        AbstractLine saleRecord;

        while ((saleRecord = reader.read()) != null) {
        }

---

分区十进制

另一个Mainframe-Cobol数字格式为Zoned-Decimal。它是一种文本格式，其中最后一位数字的符号为 Over-typed 。在分区十进制 123 是 12C ，而 -123 是 12L 。

---

Zoned Decimal

Another Mainframe-Cobol numeric format is Zoned-Decimal. It is a text format where the sign is Over-typed on the last digit. In zoned-decimal 123 is "12C" while -123 is "12L".

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