import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** 自定义拦截器，如身份验证、权限控制、登录拦截等、* 1、实现HandlerInterceptor* 2、实现Spring的WebRequestInterceptor*/
public class HttpInterceptor implements HandlerInterceptor {/*** 请求执行之前进行调用,对请求进行预处理，* 返回true之后可继续往下执行调用下一个Interceptor。或者Controller* ,返回false终止请求*/@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("请求前拦截");return true;}/*** 执行完Controller之后 && DispatcherServlet进行视图渲染之前执行*/@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("请求完成后的操作...");}/*** DispatcherServlet渲染之后取执行。可以用于资源清理等工作*/@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("视图渲染之后...");}
}

/*** WebMvcConfigurerAdapter 自定义拦截器集成WebMvcConfigurerAdapter，SpringBoot 2.0 后，该类被标记为@Deprecated.后的版本中会被取消* 解决办法* 1、实现WebMvcConfigurer （推荐）* 2、继承WebMvcConfigurationSupport*/
// 该注解表示将类交给spring进行管理
@Configuration
public class WebAppConfig implements WebMvcConfigurer {@Overridepublic void addInterceptors(InterceptorRegistry registry) {/*** 可以添加多个拦截器*/registry.addInterceptor(new HttpInterceptor()).addPathPatterns("/**");/*** 也可以添加多个拦截器* registry.addInterceptor(new HttpInterceptor1());*/}
}

 /*** RequestMapping 将Http请求映射到方法上*/@RequestMapping("/")public String HelloWorld() {System.out.println("Http请求已发出");return "Hello World";}

2019-01-06 00:32:32.168  INFO 69288 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-01-06 00:32:32.168  INFO 69288 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2019-01-06 00:32:32.173  INFO 69288 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 5 ms
请求前拦截
Http请求已发出
请求完成后的操作...
视图渲染之后...