Servlet uses cookies to realize the last login time of users

problem ： Exception encountered

An invalid character [32] was present in the Cookie value

reason ：

A space appears when formatting the time ,cookie Spaces are not allowed in the value of

//  Get the current time 
long currentTimeMillis = System.currentTimeMillis();
String pattern = "yyyy-MM-dd HH:mm:ss";
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern, Locale.getDefault());
String time = simpleDateFormat.format(currentTimeMillis);

terms of settlement ：

Send... To the client cookie Time to time utf-8 code , Decode it when you use it

//  hold time Encoding 
time = URLEncoder.encode(time, "utf-8");

// Take from cookie Get the time to decode 
value = URLDecoder.decode(value, "utf-8");