70.10 Use Tomcat’s LegacyCookieProcessor

The embedded Tomcat used by Spring Boot does not support "Version 0" of the Cookie format out of the box, and you may see the following error:

java.lang.IllegalArgumentException: An invalid character [32] was present in the Cookie value

If at all possible, you should consider updating your code to only store values compliant with later Cookie specifications. If, however, you’re unable to change the way that cookies are written, you can instead configure Tomcat to use a LegacyCookieProcessor. To switch to the LegacyCookieProcessor use an EmbeddedServletContainerCustomizer bean that adds a TomcatContextCustomizer:

_@Bean_
public EmbeddedServletContainerCustomizer cookieProcessorCustomizer() {
    return new EmbeddedServletContainerCustomizer() {

        _@Override_
        public void customize(ConfigurableEmbeddedServletContainer container) {
            if (container instanceof TomcatEmbeddedServletContainerFactory) {
                ((TomcatEmbeddedServletContainerFactory) container)
                        .addContextCustomizers(new TomcatContextCustomizer() {

                    _@Override_
                    public void customize(Context context) {
                        context.setCookieProcessor(new LegacyCookieProcessor());
                    }

                });
            }
        }

    };
}