//import java.util.Base64;
private static String toBase64v2(String str) throws UnsupportedEncodingException {
//编码
Base64.Encoder encoder = Base64.getEncoder();
String s = encoder.encodeToString(str.getBytes());
System.out.println(s);
//解码
Base64.Decoder decoder = Base64.getDecoder();
String s1 = new String(decoder.decode(s), "UTF-8");
System.out.println(s1);
return "";
}