public static String encodeToBase64String(byte[] sArr, boolean lineSep) {
        // Reuse char[] since we can't create a String incrementally anyway and StringBuffer/Builder would be slower.
        return new String(encodeToChar(sArr, lineSep));
    }
Encodes a raw byte array into a BASE64 <code>String</code> representation i accordance with RFC 2045.

@param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
@param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a little faster.
@return A BASE64 encoded array. Never <code>null</code>.
fastjson1-compatible/src/test/java/com/alibaba/fastjson/TestUtils.java