java - 将c#函数代码转换为java

Question

我正在尝试将 c# 代码转换为 java。下面是函数 在 C# 中，他们使用以下值调用此函数

FFFFFF7A0007E90300000164200401010220537769706520477269646B6579206F7200000000000000000020696E70757420796F75722063656C6C2023000000000000000020666F72206672656520747269616C00000000000000000000002000000000000000000000000000000000000000000000000000000002

他们正在将上面由十六进制值组成的字符串转换为字节数组，并且长度为124

Calculate_Checksum(convertedByteArray,0, 124);

它返回的校验和值为“A8”(返回值)

static public byte Calculate_Checksum(ref byte[] data, ushort byteToStart, UInt16 length)
{
    /* CRC Checksum Lookup Table */
    byte[] crc_lookup_table = new byte[256]
        {
          0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
          157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
          35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
          190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
          70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
          219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
          101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
          248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
          140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
          17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
          175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
          50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
          202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
          87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
          233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
          116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
        };
    ushort x;
    byte CRC_data;

    CRC_data = 0;
    for (x = byteToStart; x < length; x++)
    {
        CRC_data = crc_lookup_table[(byte)(CRC_data ^ data[x])];
    }

    return (CRC_data);
}

我已通过逗号分隔符将该值分配给字符串，例如

String checkSum = "0,94,188,226,......... 

并尝试转换为字节数组

String[] bytesString = checkSum.split(","); 
byte[] bytes = new byte[bytesString.length]; 

for(int i = 0 ; i < bytes.length ; ++i) 
{ 
    crc_lookup_table[i] = Byte.parseByte(bytesString[i]); 
} 

我在线程“main”中收到以下错误异常

java.lang.NumberFormatException: Value out of range. Value:"188" Radix:10 at java.lang.Byte.parseByte(Byte.java:150) at java.lang.Byte.parseByte(Byte.java:174) at com.axxera.tellus.gridbot.CalculatingChecksum.Calculate_Checksum1(CalculatingChe‌​cksum.java:68) at com.axxera.tellus.gridbot.CalculatingChecksum.main(CalculatingChecksum.java:18)

下面是完整的Java代码

public static void main(String[] args) {

    CalculatingChecksum checksum = new CalculatingChecksum();

    String originalMessage =     "FFFFFF7A0007E90300000164200401010220537769706520477269646B6579206F7200000000000000000020696E70757420796F75722063656C6C2023000000000000000020666F72206672656520747269616C00000000000000000000002000000000000000000000000000000000000000000000000000000002";//A8

    byte[] array = checksum.hexStringToByteArray(originalMessage);

    System.out.println("byte length--"+array.length);

    byte checksumValue = checksum.Calculate_Checksum1(array, 0, 124);

        System.out.println("Checksum value---"+checksumValue);

}
public byte[] hexStringToByteArray(String s) {
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                + Character.digit(s.charAt(i+1), 16));
    }
    return data;
}


public byte Calculate_Checksum1(byte[] data, int byteToStart, int length)  {
    /* CRC Checksum Lookup Table */
    System.out.println("before array declaration");

    byte[] crc_lookup_table = new byte[]{
        0, 94, (byte)188,(byte) 226, 97, 63,(byte) 221, (byte)131,(byte) 194,(byte) 156, 126, 32,(byte) 163,(byte) 253, 31, 65,
        (byte) 157,(byte) 195, 33, 127,(byte) 252,(byte) 162, 64, 30, 95, 1,(byte) 227,(byte) 189, 62, 96, (byte)130,(byte) 220,
        35, 125,(byte) 159,(byte) 193, 66, 28,(byte) 254,(byte) 160,(byte) 225,(byte) 191, 93, 3,(byte) 128,(byte) 222, 60, 98,
        (byte) 190,(byte) 224, 2, 92,(byte) 223,(byte) 129, 99, 61, 124, 34,(byte) 192,(byte) 158, 29, 67,(byte) 161,(byte) 255,
        70, 24,(byte) 250,(byte) 164, 39, 121,(byte) 155,(byte) 197,(byte) 132,(byte) 218, 56, 102,(byte) 229,(byte) 187, 89, 7,
        (byte) 219,(byte) 133, 103, 57,(byte) 186,(byte) 228, 6, 88, 25, 71,(byte) 165,(byte) 251, 120, 38,(byte) 196,(byte) 154,
        101, 59,(byte) 217,(byte) 135, 4, 90,(byte) 184,(byte) 230,(byte) 167,(byte) 249, 27, 69,(byte) 198,(byte) 152, 122, 36,
        (byte) 248,(byte) 166, 68, 26,(byte) 153,(byte) 199, 37, 123, 58, 100,(byte) 134,(byte) 216, 91, 5,(byte) 231,(byte) 185,
        (byte) 140,(byte) 210, 48, 110,(byte) 237,(byte) 179, 81, 15, 78, 16,(byte) 242,(byte) 172, 47, 113,(byte) 147,(byte) 205,
        17, 79,(byte) 173,(byte) 243, 112, 46,(byte) 204,(byte) 146,(byte) 211,(byte) 141, 111, 49,(byte) 178,(byte) 236, 14, 80,
        (byte) 175,(byte) 241, 19, 77,(byte) 206,(byte) 144, 114, 44, 109, 51,(byte) 209,(byte) 143, 12, 82,(byte) 176,(byte) 238,
        50, 108,(byte) 142,(byte) 208, 83, 13,(byte) 239,(byte) 177,(byte) 240,(byte) 174, 76, 18,(byte) 145,(byte) 207, 45, 115,
        (byte) 202,(byte) 148, 118, 40,(byte) 171,(byte) 245, 23, 73, 8, 86,(byte) 180,(byte) 234, 105, 55,(byte) 213,(byte) 139,
        87, 9,(byte) 235,(byte) 181, 54, 104,(byte) 138,(byte) 212,(byte) 149,(byte) 203, 41, 119,(byte) 244,(byte) 170, 72, 22,
        (byte) 233,(byte) 183, 85, 11,(byte) 136,(byte) 214, 52, 106, 43, 117,(byte) 151,(byte) 201, 74, 20,(byte) 246,(byte) 168,
        116, 42,(byte) 200,(byte) 150, 21, 75,(byte) 169,(byte) 247,(byte) 182,(byte) 232, 10, 84,(byte) 215,(byte) 137, 107, 53
      };                

    System.out.println("after array declaration");

    /*String[] bytesString = checkSum.split(",");
    byte[] bytes = new byte[bytesString.length];
    for(int i = 0 ; i < bytes.length ; ++i) {
        crc_lookup_table[i] = Byte.parseByte(bytesString[i]);
    }*/

    int x;
            byte CRC_data;

            CRC_data = 0;
            for (x = 1; x < length; x++)
            {
                System.out.println("X value"+(byte)(CRC_data ^ data[x]));
                CRC_data = crc_lookup_table[(byte)(CRC_data ^ data[x])];
            }

            return (CRC_data);
}

}

并且显示以下错误

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at com.axxera.sample.dto.CalculatingChecksum.Calculate_Checksum1(CalculatingChecksum.java:81)
at com.axxera.sample.dto.CalculatingChecksum.main(CalculatingChecksum.java:18)

Answer 1

我认为存在几个问题，并且您一直在尝试解决一个又一个问题。最后一个错误显示 ArrayIndexOutOfBoundsException: -1因为在

CRC_data = crc_lookup_table[(byte)(CRC_data ^ data[x])];

当 (byte)(CRC_data ^ data[x])是 0xFF ，这意味着-1在byte .

byte范围介于 -128 之间至127 。您需要注意负值。像这样的东西:

byte b = (byte)(CRC_data ^ data[x]);
CRC_data = crc_lookup_table[(b < 0) ? 256+b : b];

顺便说一句，你for循环从 x = 1 开始。在原始版本中它是 x = byteToStart .