Cookies are commonly used for session management, tracking user's browsing activity (ad clicks, page visits), storing stateful information (items added to the shopping cart), and much more. They provide a way to persist data that is needed across HTTP requests. Cookies are automatically sent with each HTTP request (visiting a web page, submitting a form, making an asynchronous Ajax request, etc.) by the client.
In this short tutorial, you will learn how to read cookies in a Spring Boot web application. There are multiple ways available to read cookies.
Using @CookieValue
Annotation
The simplest way to read a cookie value in Spring Boot is by using the @CookieValue
annotation. It indicates that the controller's method parameter is bound to an HTTP cookie. Here is an example:
@GetMapping("/profile")
public String profilePage(@CookieValue(name = "color") String color) {
return "You are using " + color + " mode.";
}
The @CookieValue
annotation takes several parameters:
name
— The name of the cookie to bind the method's parameter.required
— Whether the cookie is required. Defaults totrue
, leading to an exception if the cookie is missing in the request. Switching this tofalse
will set the cookie value tonull
if the cookie is absent from the request.defaultValue
— The default value to use as a fallback. Passing a default value will automatically setrequired
to false.
In the example above if a cookie with the name color is present in the HTTP request, the variable color
will contain its value. Otherwise, if the cookie is missing from the request, you will get an exception.
Let us supply a defaultValue
to avoid the runtime exception:
@GetMapping("/profile")
public String profilePage(@CookieValue(name = "color", defaultValue = "dark") String color) {
return "You are using " + color + " mode.";
}
You can also bind multiple cookies to method's parameters by using the @CookieValue
annotation:
@GetMapping("/profile")
public String profilePage(@CookieValue(name = "name", defaultValue = "Atta") String name,
@CookieValue(name = "country", defaultValue = "PK") String country) {
return "I'm " + name + " from " + country;
}
Using WebUtils
Class
The WebUtils class provides built-in utilities for web applications to manipulate the incoming HTTP requests. Using this utility class, we can easily fetch information from the request object.
The getCookie()
method from WebUtils
class returns the first cookie with the given name. If no cookie is found in the request, it will return a null
value. Let us have an example:
@GetMapping("/profile")
public String profilePage(HttpServletRequest request) {
Cookie name = WebUtils.getCookie(request, "name");
if (name != null) {
return "My name is " + name.getValue();
} else {
return "Not found!";
}
}
Using HttpServletRequest
Class
The HttpServletRequest
class provides request information for HTTP servlets. You can call the getCookies()
method on its object to retrieve an array of Cookie
objects that the client sent with this request. This method returns null
if no cookies were sent.
@GetMapping("/preferences")
public String preferencesPage(HttpServletRequest request) {
Cookie[] cookies = request.getCookies();
if (cookies != null) {
return Arrays.stream(cookies)
.map(c -> c.getName() + "=" + c.getValue())
.collect(Collectors.joining(", "));
}
return "No preferences found!";
}
Check out how to use cookies in Spring Boot tutorial to find out more examples for reading and writing cookies in Spring Boot.
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