java中String\十六进制String\byte[]之间相互转换函数

 public static String stringToHexString(String strPart) {
        String hexString = "";
        for (int i = 0; i < strPart.length(); i++) {
            int ch = (int) strPart.charAt(i);
            String strHex = Integer.toHexString(ch);
            hexString = hexString + strHex;
        }
        return hexString;
    }

private static String hexString="0123456789ABCDEF";

public static String encode(String str)
{
// 根据默认编码获取字节数组
byte[] bytes=str.getBytes();
StringBuilder sb=new StringBuilder(bytes.length*2);
// 将字节数组中每个字节拆解成2位16进制整数
for(int i=0;i<bytes.length;i++)
{
sb.append(hexString.charAt((bytes[i]&0xf0)>>4));
sb.append(hexString.charAt((bytes[i]&0x0f)>>0));
}
return sb.toString();
}

public static String decode(String bytes)
{
ByteArrayOutputStream baos=new ByteArrayOutputStream(bytes.length()/2);
// 将每2位16进制整数组装成一个字节
for(int i=0;i<bytes.length();i+=2)
baos.write((hexString.indexOf(bytes.charAt(i))<<4 |hexString.indexOf(bytes.charAt(i+1))));
return new String(baos.toByteArray());
}

private static byte uniteBytes(byte src0, byte src1) {
     byte _b0 = Byte.decode("0x" + new String(new byte[] {src0})).byteValue();
     _b0 = (byte) (_b0 << 4);
     byte _b1 = Byte.decode("0x" + new String(new byte[] {src1})).byteValue();
     byte ret = (byte) (_b0 | _b1);
     return ret;

public static byte[] HexString2Bytes(String src)
{
   byte[] ret = new byte[6];
   byte[] tmp = src.getBytes();
   for(int i=0; i<6; ++i )
   {
    ret[i] = uniteBytes(tmp[i*2], tmp[i*2+1]);
      }
   return ret;
}

 
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java 格式化输出十六进制数
   // 以16进制输出文件内容, 每16个数换行一次
   for(int i = 0; i < nLen; i++)
   {
    if(i % 16 == 0)
     System.out.println();
    String strHex = new String();
    strHex = Integer.toHexString(chBuf[i]).toUpperCase();
    if(strHex.length() > 3)
     System.out.print(strHex.substring(6));
    else
     if(strHex.length() < 2)
      System.out.print("0" + strHex);
     else
      System.out.print(strHex);
   
    System.out.print(" ");
   }
 输出结果
-----------------------------------------------------------------------
FF D8 FF E0 00 10 4A 46 49 46 00 01 01 00 00 01
00 01 00 00 FF E1 00 E6 45 78 69 66 00 00 49 49
2A 00 08 00 00 00 05 00 12 01 03 00 01 00 00 00
01 00 00 00 31 01 02 00 1C 00 00 00 4A 00 00 00
32 01 02 00 14 00 00 00 66 00 00 00 13 02 03 00
01 00 00 00 01 00 00 00 69 87 04 00 01 00 00 00
7A 00 00 00
 =================================
当我们把string字符串转成byte[]后，要再转成string 通过String.valueof()是实现不了的，只能new string(byte [])。