Controller:
byteArr = ConversionUtil.file2Byte(filePath); result = new String(byteArr,"utf-8");
filter:
String content = wrapResponse.getContent();
responseBodyMw = new BASE64Encoder().encode(content.getBytes("utf-8"));
/**
 * @Author: kiki
 * @Date: 2018/12/26
 */
public class ByteConvertUtil {
    public static String bytesToHexString(byte[] bArr) {
        StringBuffer sb = new StringBuffer(bArr.length);
        String sTmp;
        for (int i = 0; i < bArr.length; i++) {
            sTmp = Integer.toHexString(0xFF & bArr[i]);
            if (sTmp.length() < 2){
                sb.append(0);
            }
            sb.append(sTmp.toUpperCase());
        }
        return sb.toString();
    }
    /**
     * hex字符串转byte数组
     * @param inHex 待转换的Hex字符串
     * @return  转换后的byte数组结果
     */
    public static byte[] hexToByteArray(String inHex){
        int hexlen = inHex.length();
        byte[] result;
        if (hexlen % 2 == 1){
            //奇数
            hexlen++;
            result = new byte[(hexlen/2)];
            inHex="0"+inHex;
        }else {
            //偶数
            result = new byte[(hexlen/2)];
        }
        int j=0;
        for (int i = 0; i < hexlen; i+=2){
            result[j]=(byte)Integer.parseInt(inHex.substring(i,i+2),16);
            j++;
        }
        return result;
    }
}
原文:https://www.cnblogs.com/kaile/p/10197272.html