server.servlet.context-path: /api

import org.apache.commons.lang.StringUtils;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
@Configuration
@Order(1)
@WebFilter(filterName = "urlFilter", urlPatterns = "/api/*")
public class UrlFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        String servletPath = httpRequest.getServletPath();
        if (StringUtils.isNotBlank(servletPath) && servletPath.startsWith("/api")) {
            String newPath = servletPath.substring(4);
            request.getRequestDispatcher(newPath).forward(request, response);
        } else {
            chain.doFilter(request, response);
        }
    }
    @Override
    public void destroy() {
    }
}

server.port: 8081
server.context-path: /demo