十六进制编码解码，java

public class ByteHexMain {

    public static void main(String[] args) throws Exception {

        String source = "study hard and make progress everyday";

        System.out.println("source : "+source);

        String hexStr = bytes2HexStr(source.getBytes("utf8"));  //编码

        System.out.println("encode result : "+ hexStr);

        String rawSource = new String(hexStr2Bytes(hexStr),"utf8");  //解码

        System.out.println("decode result : "+rawSource);

    }

    //byte转为hex串

    static String bytes2HexStr(byte[] byteArr) {

        if (null == byteArr || byteArr.length < 1) return "";

        StringBuilder sb = new StringBuilder();

        for (byte t : byteArr) {

            if ((t & 0xF0) == 0) sb.append("0");

            sb.append(Integer.toHexString(t & 0xFF));  //t & 0xFF 操作是为去除Integer高位多余的符号位（java数据是用补码表示）

        }

        return sb.toString();

    }

    //hex串转为byte

    static byte[] hexStr2Bytes(String hexStr) {

        if (null == hexStr || hexStr.length() < 1) return null;

        int byteLen = hexStr.length() / 2;

        byte[] result = new byte[byteLen];

        char[] hexChar = hexStr.toCharArray();

        for(int i=0 ;i<byteLen;i++){

          result[i] = (byte)(Character.digit(hexChar[i*2],16)<<4 | Character.digit(hexChar[i*2+1],16));

        }

        return result;

    }

}

运行结果：

source : study hard and make progress everyday

encode result : 7374756479206861726420616e64206d616b652070726f6772657373206576657279646179

decode result : study hard and make progress everyday

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