Cookie usage Issues in Java (message:invalid character [+] is present in the cookie value)

1, problem description

The following code is executed in the servlet:

 Public voidDoget (HttpServletRequest request, httpservletresponse response)throwsservletexception, IOException {response.setcontenttype ("Text/html;charset=utf-8"); System.out.println (NewDate (). toString ()); Cookie Cookie=NewCookie ("Lasttime",NewDate (). toString ());        Response.addcookie (cookie); String s= "You are welcome to visit this website for the first time!" ~"; Cookie[] Cookies=request.getcookies (); if(Cookies! =NULL)             for(Cookie cs:cookies) {if(Cs.getname (). Equals ("Lasttime") ) {s= "The last time you logged in was:" + cs.getvalue (). Replace ("-", "");    }} response.getwriter (). print (s); }

Throws the following exception:

2, traced

It is strange to have the above problem, because the program compiles through, at least proves that there is no syntax error, according to the compiler hint, locate the problem to:

Cookie cookie = new Cookie ("Lasttime",  new Date (). toString ()); Response.addcookie (cookie);

View Javaee-api and find the following

Go back and look at the code and find

input:    New Date (). toString ());

output:   21:56:39 CST 2018

It is obvious that there are spaces in the output string, so the program will error and there are invalid characters.

3. Solutions

The solution to the problem is very simple, as long as there is no space in the string can be successful, the following will give a few specific solutions, the program is modified as follows:

Fayi

Idea: With "-" instead", then remember to change back, the program runs successfully.  Public voidDoget (HttpServletRequest request, httpservletresponse response)throwsservletexception, IOException {response.setcontenttype ("Text/html;charset=utf-8"); System.out.println (NewDate (). toString ()); Cookie Cookie=NewCookie ("Lasttime",NewDate (). ToString (). Replace ("", "-")); Cookie.setmaxage (60*60);        Response.addcookie (cookie); String s= "You are welcome to visit this website for the first time!" ~"; Cookie[] Cookies=request.getcookies (); if(Cookies! =NULL)             for(Cookie cs:cookies) {if(Cs.getname (). Equals ("Lasttime") ) {s= "The last time you logged in was:" + cs.getvalue (). Replace ("-", "" ");    }} response.getwriter (). print (s); }

Law II

idea: URL encoding, and then put the encoded string into a cookie, then URL decoding can be.  Public voiddoget (httpservletrequest request, httpservletresponse response) throws Servletexception, IOException { Response.setcontenttype ("Text/html;charset=utf-8"); System. out. println (NewDate (). toString ()); Cookie Cookie=NewCookies ("Lasttime",Urlencoder.encode (new Date (). toString (), "UTF-8" )); Cookie.setmaxage ( -* -);        Response.addcookie (cookie); String s="you are welcome to visit this website for the first time! ~"; Cookie[] Cookies=request.getcookies (); if(Cookies! =NULL)             for(Cookie cs:cookies) {if(Cs.getname (). Equals ("Lasttime") ) {s="the last time you logged in was:"+Urldecoder.decode (Cs.getvalue (), "UTF-8" );    }} response.getwriter (). print (s); }

The program runs normally and meets the expected value.

Cookie usage Issues in Java (message:invalid character [+] is present in the cookie value)