如何为Spring Boot应用添加根上下文，排除/login路径？

首先明确：Spring Boot没有server.servlet.context-path-exclude这个配置项，你之前的配置自然不会生效。下面提供几种可行的解决思路：

方案1：注册多个DispatcherServlet #

通过自定义Servlet注册Bean，让主应用处理带/applicationName前缀的路径，同时单独注册一个DispatcherServlet处理/login路径，共享同一个Spring上下文：

@Configuration
public class ServletConfig {

    // 主应用DispatcherServlet：处理/applicationName/**路径
    @Bean
    public ServletRegistrationBean<DispatcherServlet> mainDispatcherServlet(ApplicationContext context) {
        DispatcherServlet servlet = new DispatcherServlet(context);
        ServletRegistrationBean<DispatcherServlet> registration = new ServletRegistrationBean<>(servlet, "/applicationName/**");
        registration.setName("mainDispatcher");
        registration.setLoadOnStartup(1);
        return registration;
    }

    // 登录路径DispatcherServlet：处理/login路径
    @Bean
    public ServletRegistrationBean<DispatcherServlet> loginDispatcherServlet(ApplicationContext context) {
        DispatcherServlet servlet = new DispatcherServlet(context);
        ServletRegistrationBean<DispatcherServlet> registration = new ServletRegistrationBean<>(servlet, "/login");
        registration.setName("loginDispatcher");
        registration.setLoadOnStartup(2);
        return registration;
    }
}

配置完成后，需删除application.properties中的server.servlet.context-path配置，避免冲突。

方案2：用Servlet转发登录请求 #

保持server.servlet.context-path=/applicationName配置，编写一个Servlet负责转发/login请求到主应用的登录路径：

@WebServlet("/login")
public class LoginForwardServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.getRequestDispatcher("/applicationName/login").forward(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

然后在Spring Boot启动类上添加@ServletComponentScan注解，让框架扫描到这个自定义Servlet。用户访问/login时，会自动转发到/applicationName/login的处理逻辑。

方案3：通过Filter重写路径 #

编写一个Filter，将/login请求的路径重写为带根上下文的路径，交给主应用处理：

@Component
public class LoginPathRewriteFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        String path = req.getRequestURI();
        
        if ("/login".equals(path)) {
            HttpServletRequest wrappedReq = new HttpServletRequestWrapper(req) {
                @Override
                public String getRequestURI() {
                    return "/applicationName/login";
                }

                @Override
                public String getServletPath() {
                    return "/applicationName/login";
                }
            };
            chain.doFilter(wrappedReq, response);
        } else {
            chain.doFilter(request, response);
        }
    }
}

这种方式无需额外注册Servlet，仅通过路径重写实现需求，适合简单场景。

内容的提问来源于stack exchange，提问作者Raja