JAVA計算文字列UTF 8文字値

public class getUTF8Charset{

    /**
     *     UTF-8  
     * @param str        
     * @return    UTF8 
     */
    public String stringToUTF8(String str){
        return this.byteToUTF8(str.getBytes());    
    }

    /**
     * byte   16  
     */
    public String byteToUTF8(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < bytes.length; i++) {
            String hex = Integer.toHexString(bytes[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

}