spring boot的拦截器

spring boot的拦截器 1.写一个拦截类需要继承HandlerInterceptor

public class MyInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        String username = (String) session.getAttribute("username");
        if (username != null){
            System.out.println(username);
            return true;
        }
        request.getRequestDispatcher("/toLogin").forward(request,response);
        return false;
    }

2.写一个配置类，把自己写的拦截器，在配置类加上，如何需要拦截的路径和放行的路径

@Configuration
public class MyConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor())
                .addPathPatterns("/**")  //拦截的路径
                .excludePathPatterns("/toLogin","/login"); //放行的路径
    }
}