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我在解压缩从遗留系统(主机)提取的文件中的 comp3 数字时遇到问题。我尝试了由堆栈溢出成员@Jose Ventura 给出的代码,但它没有用。我试图打印解压后的数据,但没有打印出来。我对这个概念完全陌生(comp 3)。所以你们能帮我完成这个任务吗

下面是我的代码


    import java.io.IOException;
    import java.nio.file.Files;
    import java.nio.file.Path;
    import java.nio.file.Paths;
    import org.apache.commons.io.FileUtils;

    public class TestComp3 {
        private static String unpackData(byte[] packedData) {

            int decimals = 2;
            String unpackedData = "";
            final int negativeSign = 13;
            int lengthPack = packedData.length;
            int numDigits = lengthPack * 2 - 1;

            int raw = (packedData[lengthPack - 1] & 0xFF);
            int firstDigit = (raw >> 4);
            int secondDigit = (packedData[lengthPack - 1] & 0x0F);
            boolean negative = (secondDigit == negativeSign);
            int lastDigit = firstDigit;
            for (int i = 0; i < lengthPack - 1; i++) {
                raw = (packedData[i] & 0xFF);
                firstDigit = (raw >> 4);
                secondDigit = (packedData[i] & 0x0F);
                unpackedData += String.valueOf(firstDigit);
                unpackedData += String.valueOf(secondDigit);

            }
            unpackedData += String.valueOf(lastDigit);
            if (decimals > 0) {
                unpackedData = unpackedData.substring(0, numDigits - decimals) + "."
                        + unpackedData.substring(numDigits - decimals);
            }
            if (negative) {
                // System.out.println("unpacked data :-"+unpackedData);
                System.out.println("-" + unpackedData);
                return '-' + unpackedData;

            }
            System.out.println(unpackedData);
            return unpackedData;
        }
    public static void main(String[] args) {

            Path path = Paths.get("C:\\Users\\AV00499269\\Desktop\\Comp3 data file\\KYC.txt");

            try {
                byte[] data = Files.readAllBytes(path);
                TestComp3.unpackData(data);
            } catch (IOException e1) {
                // TODO Auto-generated catch block

                e1.printStackTrace();
            }

        }

    }
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1 回答 1

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您的问题是您试图获取未打包的半字节的字符串值,而这些将是不可打印的控制字符。

将您的打包数字视为一个字节数组,对于每个字节:

int endValue = 0;

for (int I = 0, I< packed.length; I++) {
  byte high = packed[I] & 0xF0;
  byte low  = packed[I] & 0x0F;
  endValue = (endValue * 10) + (high * 10) + low;
}

System.out.println("The int value is: " + endValue)

根据源系统,您需要对符号半字节进行特殊处理,如果它是负数,则乘以 -1,但我将把它作为一个特殊的练习留给读者。

于 2019-02-19T04:23:32.557 回答