切面，你会了吗？"/>

(十六)ATP应用测试平台——java应用中的过滤器Filter、拦截器Interceptor、参数解析器Resolver、Aop切面，你会了吗？

前言

过滤器Filter、拦截器Interceptor、参数解析器Resolver、Aop切面是我们应用开发中经常使用到的技术，到底该如何使用这些web附属功能， 本小节我们就分别介绍一下其各自的用法及其应用场景。

正文

过滤器

• 过滤器Filter是依赖于servlet存在的一种对web资源预处理的一种手段，不依赖于spring容器启动，是一种独立的web资源预处理器。能够对动静态资源统一拦截，统一过滤，springsecurity中就有用到过滤器的统一拦截功能，实现访问权限资源的控制。其是一种粗粒度的资源访问管理器，主要用来实现一些统一编码设置、用户访问控制等功能。
• 使用步骤

①创建一个过滤器并集成filter实现其接口，init()方法只会在项目启动时执行一次，doFilter（）方法是拦截器具体实现对资源的处理过程，destroy（）方法是在项目销毁时执行一次。

package com.yundi.atp.platform.filter;import lombok.extern.slf4j.Slf4j;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;/*** @Author: 北溟溟* @Description: 过滤器：设置编码* 优先级：过滤器>拦截器>AOP切面* 粒度：过滤器<拦截器<AOP切面* @Date: 2022/1/25 18:33* @Version: 1.0.0*/
@Slf4j
public class ParamFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) {log.info("【过滤器】init只会初始化时执行一次");}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {//设置编码HttpServletRequest request = (HttpServletRequest) servletRequest;HttpServletResponse response = (HttpServletResponse) servletResponse;request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");//记录请求花费的时间long startTime = System.currentTimeMillis();filterChain.doFilter(servletRequest, servletResponse);log.info("【过滤器】spend total time:{}ms", System.currentTimeMillis() - startTime);}@Overridepublic void destroy() {log.info("【过滤器】destroy只会销毁时执行一次");}
}

②将filter注册到FilterRegistrationBean实例中

package com.yundi.atp.platform.config;import com.yundi.atp.platform.filter.ParamFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** @Author: 北溟溟* @Description: 过滤器注册:Servlet容器级别的过滤器* @Date: 2022/1/25 18:38* @Version: 1.0.0*/
@Configuration
public class FilterConfiguration {@Beanpublic FilterRegistrationBean filterRegistrationBean() {FilterRegistrationBean registration = new FilterRegistrationBean();registration.setFilter(new ParamFilter());registration.addUrlPatterns("/*");registration.setName("paramFilter");// 设置过滤器被调用的顺序registration.setOrder(1);return registration;}
}

拦截器

• 拦截器是springmvc中对于web请求资源的处理手段之一，拦截器可以实现动态资源的拦截处理，主要用于登录认证，token校验，程序执行时间统计等等，是DispatcherServlet中对应用请求的预处理手段。能够获取到spring容器实例，实现拦截结果业务处理。
• 使用步骤

①创建一个auth注解，实现controller方法的拦截与放行，有auth注解的放行

package com.yundi.atp.platform.annotation;import java.lang.annotation.*;/*** @Author: 北溟溟* @Description: 授权注解* @Date: 2022/1/25 16:30* @Version: 1.0.0*/
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface Auth {
}

 ②创建拦截器AuthHandlerInterceptor

package com.yundi.atp.platform.interceptor;import com.yundi.atp.platform.annotation.Auth;
import com.yundi.atp.platform.module.sys.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.core.NamedThreadLocal;
import org.springframework.stereotype.Component;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** @Author: 北溟溟* @Description: 通过拦截器鉴权* @Date: 2022/1/25 16:53* @Version: 1.0.0*/
@Slf4j
@Component
public class AuthHandlerInterceptor implements HandlerInterceptor {private NamedThreadLocal<Long> startTimeThreadLocal = new NamedThreadLocal<Long>("StopWatch-StartTime");@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {//注入serviceUserService userService = this.getBean(UserService.class, request);log.info("注入service:" + userService);//设置当前时间startTimeThreadLocal.set(System.currentTimeMillis());log.info("【拦截器】方法在Controller方法执行前。。。");if ((handler instanceof HandlerMethod) && (((HandlerMethod) handler).getMethodAnnotation(Auth.class) != null)) {return true;}return verifyToken(request);}private boolean verifyToken(HttpServletRequest request) {String token = request.getHeader("token");if (StringUtils.isNotBlank(token)) {//todo 解析token,不通过返回false}return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {log.info("【拦截器】方法在Controller方法执行结束后执行。。。");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {log.info("【拦截器】在view视图渲染完成后执行。。。");log.info("【拦截器】spend total time:{}ms", System.currentTimeMillis() - startTimeThreadLocal.get());}/*** 获取容器对象实例* @param clazz* @param request* @param <T>* @return*/private <T> T getBean(Class<T> clazz, HttpServletRequest request) {WebApplicationContext applicationContext = WebApplicationContextUtils.getRequiredWebApplicationContext(request.getServletContext());return applicationContext.getBean(clazz);}
}

 ③注册拦截器

package com.yundi.atp.platform.config;import com.yundi.atp.platform.interceptor.AuthHandlerInterceptor;
import com.yundi.atp.platform.resolver.AuthHandlerMethodArgumentResolver;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;import java.util.List;/*** @Author: 北溟溟* @Description: 添加静态资源文件，外部可以直接访问地址* @Date: 2021/5/18 10:54* @Version: 1.0.0*/
@Configuration
public class MyWebMvcConfig implements WebMvcConfigurer {@Overridepublic void addResourceHandlers(ResourceHandlerRegistry registry) {registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");registry.addResourceHandler("/tinymce/**").addResourceLocations("classpath:/tinymce/");}@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new AuthHandlerInterceptor()).addPathPatterns("/**").order(1);}@Overridepublic void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {resolvers.add(new AuthHandlerMethodArgumentResolver());}
}

参数解析器

• 参数解析器HandlerMethodArgumentResolver将web请求中的参数解析为标准的数据并绑定到controller中接收，类似于@RequestBody注解，实现数据的统一处理。
• 使用步骤

①创建一个参数解析器注解

package com.yundi.atp.platform.annotation;import java.lang.annotation.*;/*** @Author: 北溟溟* @Description: 授权注解* @Date: 2022/1/25 16:30* @Version: 1.0.0*/
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface Param {
}

 ②创建一个参数解析器ParamHandlerMethodArgumentResolver

package com.yundi.atp.platform.resolver;import com.yundi.atp.platform.annotation.Param;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;import javax.servlet.http.HttpServletRequest;/*** @Author: 北溟溟* @Description: 参数解析器鉴权:其功能就是解析request请求参数并绑定数据到Controller的入参上* @Date: 2022/1/25 17:47* @Version: 1.0.0*/
@Slf4j
@Component
public class ParamHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {@Overridepublic boolean supportsParameter(MethodParameter methodParameter) {log.info("【方法解析器】参数解析器鉴权2！");return methodParameter.hasParameterAnnotation(Param.class);}@Overridepublic Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) {if (methodParameter.getParameterType().equals(String.class)) {HttpServletRequest request = nativeWebRequest.getNativeRequest(HttpServletRequest.class);String token = request.getHeader("token");return token;}return null;}
}

③注册参数解析器

/** ******************************************************************************************************************************************* Copyright (c) 2021 .* All rights reserved.* 项目名称：atp-platform* 项目描述：应用测试平台管理端* 版权说明：本软件属云嘀科技有限公司所有，在未获得云嘀科技有限公司正式授权情况下，任何企业和个人，不能获取、阅读、安装、传播本软件涉及的任何受知识产权保护的内容。* ********************************************************************************************************************************************/
package com.yundi.atp.platform.config;import com.yundi.atp.platform.interceptor.AuthHandlerInterceptor;
import com.yundi.atp.platform.resolver.ParamHandlerMethodArgumentResolver;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;import java.util.List;/*** @Author: 北溟溟* @Description: 添加静态资源文件，外部可以直接访问地址* @Date: 2021/5/18 10:54* @Version: 1.0.0*/
@Configuration
public class MyWebMvcConfig implements WebMvcConfigurer {@Overridepublic void addResourceHandlers(ResourceHandlerRegistry registry) {registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");registry.addResourceHandler("/tinymce/**").addResourceLocations("classpath:/tinymce/");}@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new AuthHandlerInterceptor()).addPathPatterns("/**").order(1);}@Overridepublic void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {resolvers.add(new ParamHandlerMethodArgumentResolver());}
}

④绑定参数解析器到controller

 @ApiOperation(value = "查询全部用户信息详情测试")@GetMapping(value = "/findAllUserInfoTest")public Result findAllUserInfoTest(@Param String id) {return Result.success(id);}

aop切面

• aop切面是spring框架的重要组件之一，在项目应用中我们主要用来做操作日志的记录，它能够获取到方法级别的入参、出参，可用作低粒度级别的web资源处理器。
• 使用步骤

①创建切面注解

package com.yundi.atp.platform.annotation;import java.lang.annotation.*;/*** @Author: 北溟溟* @Description: 日志注解* @Date: 2022/1/25 16:30* @Version: 1.0.0*/
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface OperationLog {
}

②创建日志切面OperationLogAspect

package com.yundi.atp.platform.aspect;import com.yundi.atp.platform.annotation.OperationLog;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.context.annotation.Configuration;/*** @Author: 北溟溟* @Description: 通过切面鉴权* @Date: 2022/1/25 16:34* @Version: 1.0.0*/
@Aspect
@Slf4j
@Configuration
public class OperationLogAspect {/*** 切点*/@Pointcut("@annotation(com.yundi.atp.platform.annotation.OperationLog)")public void logPointCut() {}@Around(value = "logPointCut() && @annotation(operationLog)")public void operationLogStore(JoinPoint joinPoint, OperationLog operationLog) {//todo 日志处理log.info("【切面】这是一个切面的使用！");}}

③ 应用

@Auth
@OperationLog
@ApiOperation(value = "查询全部用户信息详情")
@GetMapping(value = "/findAllUserInfo")
public Result findAllUserInfo() {List<User> userList = userService.findAllUserInfo();return Result.success(userList);
}    

结语

OK，本期内容到这里就结束了，我们下期见。。。