Change JWT Filter with optional Authentication

JWTFilter.java

package com.seelix.api.security.jwt;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.GenericFilterBean;

/**
 * Filters incoming requests and installs a Spring Security principal if a
 * header corresponding to a valid user is found.
 */
public class JWTFilter extends GenericFilterBean {

	private TokenProvider tokenProvider;

	public JWTFilter(TokenProvider tokenProvider) {
		this.tokenProvider = tokenProvider;
	}

	@Override
	public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
			throws IOException, ServletException {
		HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
		String jwt = resolveToken(httpServletRequest);
		if (StringUtils.hasText(jwt)) {
			this.tokenProvider.getAuthentication(jwt)
					.ifPresent(authentication -> SecurityContextHolder.getContext().setAuthentication(authentication));
		}
		filterChain.doFilter(servletRequest, servletResponse);
	}

	private String resolveToken(HttpServletRequest request) {
		String bearerToken = request.getHeader(JWTConfigurer.AUTHORIZATION_HEADER);
		if (StringUtils.hasText(bearerToken) && bearerToken.startsWith("Bearer ")) {
			return bearerToken.substring(7, bearerToken.length());
		}
		return null;
	}
}