1、
首先先写一个拦截器类：需要实现HandlerInterceptor

public class MineIntegerceptor implements HandlerInterceptor

2、
重写preHandle等方法，实现功能：登录验证、权限验证等

public class MineIntegerceptor implements HandlerInterceptor {
	@Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        logger.info("====>  Start: " + request.getRequestURI());
        //判断用户ID是否存在，不存在就跳转到登录界面
		Object user = request.getSession.getAttribute("loginUser");
		if(user == null){
			request.getRequestDispatcher("/login").forward(requset,response);
			request.setAttribute("msg","登录失效，请重新登录");
			return false;
		}
        return true;
    }
}

3、
创建一个扩展Mvc配置类
在自己写的MvcConfig中，addInterceptors()添加自定义的拦截器

@Configuration
public class MyMvcConfig implements WebMvcConfigurer{
	@Override
	public void addInterceptors(InterceptorRegistry registry){
		//addInterceptor 添加拦截器
		//addPathPatterns 添加拦截的路径
		//excludePathPatterns 添加拦截路径中 特殊放行的路径
		registry.addInterceptor(new MineIntegerceptor())
				.addPathPatterns("/**") 
				.excludePathPatterns("/custom");
	}
}