final Base64.Decoder decoder = Base64.getDecoder();

final Base64.Encoder encoder = Base64.getEncoder();

final String text = "字串文字";

final byte[] textByte = text.getBytes("UTF-8");

//编码

final String encodedText = encoder.encodeToString(textByte);

System.out.println(encodedText);

//解码

System.out.println(new String(decoder.decode(encodedText), "UTF-8"));