IndexDotHtmlFilter.java

import lombok.val;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
class IndexDotHtmlFilter extends OncePerRequestFilter {
    @Override
    protected void doFilterInternal(
        HttpServletRequest request,
        HttpServletResponse response,
        FilterChain filterChain
    ) throws ServletException, IOException {
        val path = request.getRequestURI().substring(request.getContextPath().length());
        if (
                !path.startsWith("/api") &&
                !path.startsWith("/wss") &&
                !path.startsWith("/ctl") &&
                !path.contains(".") &&
                 path.matches("/(.*)")
        ) {
            request.getRequestDispatcher("/index.html").forward(request, response);
        } else {
            filterChain.doFilter(request, response);
        }
    }
}