<a href="#_3">写此文档的原因</a>    <a href="#_6">参考资料</a>    <a href="#_12">简洁代码实现方式</a>    <a href="#_22">实现代码</a>    
 
  <a href="#_25">核心转码代码</a>      <a href="#_68">转换的工具类：</a>      <a href="#_169">结束</a>            

/**
    * MODBUS转码
    * （不支持小数转码）
    *
    * @param byte1 待转码数据（高位）
    * @param byte2 待转码数据（低位）
    */
   public Double byteToInt(byte byte1,byte byte2){
      //高位在前，低位在后
      //byte[] bs1 = new byte[]{(byte) 0xFF,(byte) 0x3D};      //测试数据：负数   -195
      //byte[] bs1 = new byte[]{(byte) 0x00,(byte) 0xC3};      //测试数据：正数   195
      int number = 0;
      //1、取出高位符号
      if(byte1<0){
         //负数先高位左移8位和低位拼接，再取反
         number =~(byte1<<8 | byte2);
         //补码并赋值符号位
         number =-(number+1);
      }else{
         //正数直接转成16位字符（主要为拼接字符串）
         String s = XmByteUtils.toHexAscii(new byte[]{byte1,byte2});
         //直接把16进制字符转int
         number = Integer.parseInt(s, 16);
      }
      //把已取出的数据做额外处理
      return (double) number / 10;      //具体数据处理
   }

package com.system.xiaoma.util;

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;

public class XmByteUtils {

   /**
    * MODBUS报文字符串（不带空格）转 byte可发送的HEX格式
    * @param s MODBUS报文字符串
    */
   public static byte[] fromHexAscii(String s) throws NumberFormatException {
      try {
         int len = s.length();
         if ((len % 2) != 0)
            throw new NumberFormatException("Hex ascii must be exactly two digits per byte.");

         int out_len = len / 2;
         byte[] out = new byte[out_len];
         int i = 0;
         StringReader sr = new StringReader(s);
         while (i < out_len) {
            int val = (16 * fromHexDigit(sr.read())) + fromHexDigit(sr.read());
            out[i++] = (byte) val;
         }
         return out;
      } catch (IOException e) {
         throw new InternalError("IOException reading from StringReader?!?!");
      }
   }

   /**
    *
    * @param c 需发送命令的16位数值转换
    * @return
    * @throws NumberFormatException
    */
   private static int fromHexDigit(int c) throws NumberFormatException {
      if (c >= 0x30 && c < 0x3A)
         return c - 0x30;
      else if (c >= 0x41 && c < 0x47)
         return c - 0x37;
      else if (c >= 0x61 && c < 0x67)
         return c - 0x57;
      else
         throw new NumberFormatException('\'' + c + "' is not a valid hexadecimal digit.");
   }

   /**
    * byte数组转十六位字符串（不带空格）
    * @param bytes 待转换的byte数组
    */
   public static String toHexAscii(byte[] bytes) {
      int len = bytes.length;
      StringWriter sw = new StringWriter(len * 2);
      for (int i = 0; i < len; ++i)
         addHexAscii(bytes[i], sw);
      return sw.toString();
   }

   /**
    * byte转16位并拼接
    * @param b    数组
    * @param sw   字符串
    */
   static void addHexAscii(byte b, StringWriter sw) {
      int ub = unsignedPromote(b);
      int h1 = ub / 16;
      int h2 = ub % 16;
      sw.write(toHexDigit(h1));
      sw.write(toHexDigit(h2));
   }

   /**
    * byte取补位数据
    * @param b 数组
    * @return
    */
   public static int unsignedPromote(byte b) {
      return b & 0xff;
   }

   /* note: we do no arg. checking, because    */
   /* we only ever call this from addHexAscii() */
   /* above, and we are sure the args are okay  */
   private static char toHexDigit(int h) {
      char out;
      if (h <= 9) out = (char) (h + 0x30);
      else out = (char) (h + 0x37);
      //System.err.println(h + ": " + out);
      return out;
   }
}