java util - Hex轉換工具

測試代碼

package cn.java.codec.hex;

public class Test {

    public static void main(String[] args) {
        String str = "test";
        System.out.println("test string : "+str);

        String hexEncode = HexUtil.encode(str.getBytes());
        System.out.println("HexUtil.encode Result : "+hexEncode);

        byte[] bytes = HexUtil.decode(hexEncode);
        System.out.println("HexUtil.decode Result : "+new String(bytes));
        
    }

}

輸出內容

test string : test
HexUtil.encode Result : 74657374
HexUtil.decode Result : test

 

工具類

package cn.java.codec.hex;

public class HexUtil {
    
    /**
     * 字節流轉成十六進制表示
     */
    public static String encode(byte[] src) {
        String strHex = "";
        StringBuilder sb = new StringBuilder("");
        for (int n = 0; n < src.length; n++) {
            strHex = Integer.toHexString(src[n] & 0xFF);
            sb.append((strHex.length() == 1) ? "0" + strHex : strHex); // 每個字節由兩個字符表示，位數不夠，高位補0
        }
        return sb.toString().trim();
    }
    
    /**
     * 字符串轉成字節流
     */
    public static byte[] decode(String src) {
        int m = 0, n = 0;
        int byteLen = src.length() / 2; // 每兩個字符描述一個字節
        byte[] ret = new byte[byteLen];
        for (int i = 0; i < byteLen; i++) {
            m = i * 2 + 1;
            n = m + 1;
            int intVal = Integer.decode("0x" + src.substring(i * 2, m) + src.substring(m, n));
            ret[i] = Byte.valueOf((byte)intVal);
        }
        return ret;
    }
    
}