CRC 校验

最新推荐文章于 2023-10-18 16:35:47 发布

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本文介绍了一种常用的数据通信差错校验方法——CRC（循环冗余校验），并提供了详细的CRC校验类的Java代码实现。该算法适用于各种通信场景，能够有效检测数据传输过程中的错误。

CRC即循环冗余校验码（Cyclic Redundancy Check）：是数据通信领域中最常用的一种差错校验码，其特征是信息字段和校验字段的长度可以任意选定。

import java.util.Arrays;

/**
 * @说明 CRC校验类
 * @author cuisuqiang
 * @version 1.0
 * @since
 */
public class CRCCheck {
	
	public static void main(String[] args) {
		byte[] btm = new byte[] { 12, 13, 1, 0, 0, 1, 0, 31, -19, 0, 8,
				0, 1 };
		byte[] btl = CRCCheck.getCRCByteValue(btm);
		System.out.println(Arrays.toString(btl));
	}

	/**
	 * 入口方法
	 * @param bt 需要校验的字节流
	 * @return
	 */
	public static byte[] getCRCByteValue(byte[] bt){
		char ch = caluCRC(bt);
		return charToByte(ch);
	}

	public static char[] crc_tb = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084,
			0x50a5, 0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c,
			0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5,
			0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd,
			0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6,
			0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee,
			0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7,
			0x66f6, 0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df,
			0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840,
			0x1861, 0x2802, 0x3823, 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948,
			0x9969, 0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71,
			0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79,
			0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22,
			0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a,
			0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13,
			0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b,
			0xaf3a, 0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c,
			0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004,
			0x4025, 0x7046, 0x6067, 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d,
			0xd31c, 0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235,
			0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e,
			0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466,
			0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f,
			0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657,
			0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8,
			0x89e9, 0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0,
			0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9,
			0x9bd8, 0xabbb, 0xbb9a, 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1,
			0x1ad0, 0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa,
			0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2,
			0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b,
			0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93,
			0x3eb2, 0x0ed1, 0x1ef0 };

	/**
	 * 获得CRC验证码
	 */
	public static char caluCRC(byte[] pByte) {
		int len = pByte.length;
		char crc;
		byte da;
		crc = 0x0;
		int i = 0;
		while (len-- != 0) {
			da = (byte) (crc / 256);
			crc <<= 8;
			int num = da ^ pByte[i];
			if (num < 0)
				num += 256;
			crc ^= crc_tb[num];
			++i;
		}
		return crc;
	}

	/**
	 * char 转byte
	 */
	public static byte[] charToByte(char c) {
		byte[] b = new byte[2];
		b[0] = (byte) ((c & 0xFF00) >> 8);
		b[1] = (byte) (c & 0xFF);
		return b;
	}
	
}

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