How to solve the problem that Servlet Cookie cannot get the value in java

This article mainly introduces the relevant information on the solutions to the reasons why the value cannot be obtained in Servlet Cookie in java. Friends who need it can refer to it

Solution to the reason why Servlet Cookie cannot get the value in java

Phenomena:

When testing the HTTP request with Cookie, it was found that the server used request. getHeader("cookie") can get the value; but request.getCookies() cannot

Reason:

I checked the specific cookie value of the browser and found

http://localhost:8080/

When accessing, the cookie value is placed under localhost, and the SESSIONID automatically generated by the server is also stored under the localhost path.

http://127.0.0.1:8080/

When accessing, the cookie uid value is placed under 127.0.0.1:8080, and the cookie under 127.0.0.1:8080 The Servlet on the server side can never get it; and the SESSIONID automatically generated by the server is under 127.0.0.1, which is different from the uid storage location. So when the server sends a cookie,

 Cookie mycookies[] = request.getCookies();

needs to be changed to

String host=request.getHeader("host");

or abandon the setting

if(host.indexOf(":")>-1){
  host=host.split(":")[0];
  }

so that the cookie value is also saved at 127.0 Under .0.1, it is not related to the port number

Of course, if the server already has a domain name, there will be no cookie value that cannot be obtained under the port number

Solution ：

mycookie.setDomain(host);

Add the previous line to get it,

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