SpringMVC--过滤器/拦截器/AOP

一时失言乱红尘 2022-12-03 09:22 213阅读 0赞

# 其他网址 #

> [spring boot 过滤器、拦截器的区别与使用\_hwm的专栏-CSDN博客][spring boot _hwm_-CSDN]

# 简介 #

执行顺序为：监听器 => 过滤器=> 拦截器

# 过滤器/拦截器/AOP #

**其他网址**

> [spring boot 过滤器、拦截器的区别与使用\_hwm的专栏-CSDN博客][spring boot _hwm_-CSDN]  
> [Spring Interceptor vs Filter 拦截器和过滤器区别 | ASPIRE][Spring Interceptor vs Filter _ _ ASPIRE]
> 
> 过滤器：《JSP&Servlet学习笔记》=> 5.3过滤器  
> 拦截器：《深入浅出Spring Boot2.x》

**简介**

>  *  过滤器：Filter。拦截器：Interceptor 。
>  *  在Spring构架的程序中，要优先使用拦截器。几乎所有 Filter 能够做的事情，interceptor 都能够轻松的实现。
>  *  AOP:可以自定义切入的点，有方法的参数，但拿不到http请求，可以通过RequestContextHolder等方式获得。  
>     AOP用法见：[SpringAOP系列--AOP+注解 实例\_feiying0canglang的博客-CSDN博客][SpringAOP_--AOP_ _feiying0canglang_-CSDN]

**调用顺序**

> 过滤前=> 拦截前=> AOP=> Controller=> AOP=> 拦截后=> 过滤后
> 
> ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NjY0OTA2_size_16_color_FFFFFF_t_70][]
> 
> ![70][]

**不同点**

> <table> 
> <tbody> 
> <tr> 
> <td style="width:124px;">项</td> 
> <td style="width:169px;">过滤器</td> 
> <td style="width:267px;">拦截器</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">使用场景</td> 
> <td style="width:169px;">对请求/响应进行修改、判断等。一般用于过滤参数、登录权限验证、资源访问权限控制、敏感词汇过滤、字符编码转换。</td> 
> <td style="width:267px;">在service或者一个方法前/后调用一个方法，或者在方法后调用一个方法。</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">能力</td> 
> <td style="width:169px;"> 可以拿到原始的http请求与响应，拿不到请求的控制器和请求控制器中的方法的信息。 可以修改请求、响应、参数：比如：修改字符编码、删除低俗文字、删除危险字符、修改参数 </td> 
> <td style="width:267px;">可以拿到你请求的控制器和方法，却拿不到请求与响应。</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">顺序</td> 
> <td style="width:169px;">可指定顺序。</td> 
> <td style="width:267px;">可指定顺序。</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">实现方式</td> 
> <td style="width:169px;">回调函数</td> 
> <td style="width:267px;">AOP</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">使用范围</td> 
> <td style="width:169px;">只能用于Web</td> 
> <td style="width:267px;">可用于Web、Application、Swing</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">作用范围</td> 
> <td style="width:169px;">所有请求。</td> 
> <td style="width:267px;">只能是controller请求。静态资源无法控制。</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">使用位置</td> 
> <td style="width:169px;">controller前后、dispaterServlet前后</td> 
> <td style="width:267px;">controller前后</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">规范定义</td> 
> <td style="width:169px;"> Servlet 规范定义，Servlet 容器支持。 Filter 接口定义在 javax.servlet 包 </td> 
> <td style="width:267px;"> Spring容器内，Spring框架支持。 HandlerInterceptor 接口 定义在org.springframework.web.servlet 包 </td> 
> </tr> 
> <tr> 
> <td style="width:124px;">灵活性/粒度</td> 
> <td style="width:169px;"> 灵活性差（粒度大）。 不能够使用 Spring 容器资源 </td> 
> <td style="width:267px;"> 灵活性好（粒度小）。 能使用Spring里的任何资源、对象，例如 Service对象、数据源、事务管理等，通过IoC注入到拦截器即可。 </td> 
> </tr> 
> <tr> 
> <td style="width:124px;">打断链路</td> 
> <td style="width:169px;">打断方法：处理请求和响应对象来引发中断，需要额外的动作，比如将用户重定向到错误页面。</td> 
> <td style="width:267px;">打断方法：preHandle方法内返回 false</td> 
> </tr> 
> <tr> 
> <td style="width:124px;">执行次数</td> 
> <td style="width:169px;"> 一个controller周期只调用一次：一个过滤器实例只能在容器初始化时调用一次。 </td> 
> <td style="width:267px;">一个controller周期可调用多次</td> 
> </tr> 
> </tbody> 
> </table>

# 公共代码 #

package com.example.controller;
    
    import com.example.entity.User;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/hello")
    public class HelloController {
        @RequestMapping("/test1")
        public User test1(User user) {
            System.out.println("HelloController.test1");
            return user;
        }
    }

# 过滤器 #

**其他网址**

> [servlet过滤器][servlet]

## 简介 ##

**说明**

> Filter可以有多个。一个filter执行完之后会执行另外一个。

**JavaDoc对过滤器使用场景的描述**

> Examples that have been identified for this design are 
> (1) Authentication Filters, //用户访问权限过滤 
> (2) Logging and Auditing Filters, //日志过滤，可以记录特殊用户的特殊请求的记录等 
> (3) Image conversion Filters 
> (4) Data compression Filters 
> (5) Encryption Filters 
> (6) Tokenizing Filters //过滤Token 
> (7) Filters that trigger resource access events 
> (8) XSL/T filters 
> (9) Mime-type chain Filter

## 实例（单过滤器） ##

> 两种方式注册filter（两种方式的本质都是一样的，都是去FilterRegistrationBean注册自定义Filter ）：  
> 1、使用spring boot提供的FilterRegistrationBean注册Filter  
> 2、使用原生servlet注解定义Filter。缺点：无法指定过滤器顺序

**注册方式1：FilterRegistrationBean**

> **定义Filter**
> 
>     package com.example.filter;
>     
>     import javax.servlet.*;
>     import javax.servlet.http.HttpServletRequest;
>     import java.io.IOException;
>     
>     public class MyFilter implements Filter {
>         @Override
>         public void init(javax.servlet.FilterConfig filterConfig) throws ServletException {
>             System.out.println("MyFilter.init");
>             System.out.println("  过滤器名：" + filterConfig.getFilterName());
>         }
>     
>         @Override
>         public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
>             // do something 处理request 或response
>             System.out.println("MyFilter.doFilter");
>     
>             if (servletRequest instanceof HttpServletRequest) {
>                 System.out.println("  URL:" + ((HttpServletRequest)servletRequest).getRequestURL());
>             }
>     
>             // 调用filter链中的下一个filter
>             filterChain.doFilter(servletRequest,servletResponse);
>         }
>     
>         @Override
>         public void destroy() {
>             System.out.println("MyFilter.destroy");
>         }
>     }

> 注册自定义Filter
> 
>     package com.example.filter;
>     
>     import org.springframework.boot.web.servlet.FilterRegistrationBean;
>     import org.springframework.context.annotation.Bean;
>     import org.springframework.context.annotation.Configuration;
>     
>     @Configuration
>     public class FilterConfig {
>     
>         @Bean
>         public FilterRegistrationBean registrationBean() {
>             FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter());
>             filterRegistrationBean.addUrlPatterns("/*");
>             return filterRegistrationBean;
>         }
>     }

**注册方式2：@WebFilter**

>     package com.example.filter;
>     
>     import org.springframework.stereotype.Component;
>     
>     import javax.servlet.*;
>     import javax.servlet.annotation.WebFilter;
>     import javax.servlet.http.HttpServletRequest;
>     import java.io.IOException;
>     
>     @Component
>     // 定义filterName 和过滤的url
>     @WebFilter(filterName = "myFilter" ,urlPatterns = "/*")
>     public class MyFilter implements Filter {
>         @Override
>         public void init(FilterConfig filterConfig) throws ServletException {
>             System.out.println("MyFilter.init");
>             System.out.println("  过滤器名：" + filterConfig.getFilterName());
>         }
>         @Override
>         public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
>             // do something 处理request 或response
>             System.out.println("MyFilter.doFilter");
>     
>             if (servletRequest instanceof HttpServletRequest) {
>                 System.out.println("  URL:" + ((HttpServletRequest)servletRequest).getRequestURL());
>             }
>     
>             // 调用filter链中的下一个filter
>             filterChain.doFilter(servletRequest,servletResponse);
>         }
>         @Override
>         public void destroy() {
>             System.out.println("MyFilter.destroy");
>         }
>     }

**测试结果**

> 启动SpringBoot
> 
>     2020-09-04 23:25:27.216  INFO 16948 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
>     2020-09-04 23:25:27.216  INFO 16948 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 781 ms
>     MyFilter.init
>       过滤器名：myFilter
>     2020-09-04 23:25:27.361  INFO 16948 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
>     2020-09-04 23:25:27.493  INFO 16948 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
>     2020-09-04 23:25:27.501  INFO 16948 --- [           main] com.example.DemoApplication              : Started DemoApplication in 1.44 seconds (JVM running for 2.276)
>     2020-09-04 23:25:40.252  INFO 16948 --- [nio-8080-exec-2] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
>     2020-09-04 23:25:40.253  INFO 16948 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
>     2020-09-04 23:25:40.257  INFO 16948 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Completed initialization in 4 ms

> postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果：
> 
>     MyFilter.doFilter
>       URL:http://localhost:8080/hello/test1
>     HelloController.test1
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

> 关闭SpringBoot
> 
>     Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'
>     MyFilter.destroy
>     2020-09-04 23:26:00.810  INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

## 实例（多过滤器） ##

**过滤器1**

package com.example.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import java.io.IOException;
    
    public class MyFilter1 implements Filter {
        @Override
        public void init(javax.servlet.FilterConfig filterConfig) throws ServletException {
            System.out.println("MyFilter1.init");
            System.out.println("  过滤器名：" + filterConfig.getFilterName());
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, 
                FilterChain filterChain) throws IOException, ServletException {
            // do something 处理request 或response
            System.out.println("MyFilter1.doFilter");
    
            if (servletRequest instanceof HttpServletRequest) {
                System.out.println("  URL:" + ((HttpServletRequest)servletRequest).getRequestURL());
            }
    
            // 调用filter链中的下一个filter
            filterChain.doFilter(servletRequest,servletResponse);
        }
    
        @Override
        public void destroy() {
            System.out.println("MyFilter1.destroy");
        }
    }

**过滤器2**

package com.example.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import java.io.IOException;
    
    public class MyFilter2 implements Filter {
    
        @Override
        public void init(javax.servlet.FilterConfig filterConfig) throws ServletException {
            System.out.println("MyFilter2.init");
            System.out.println("  过滤器名：" + filterConfig.getFilterName());
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, 
                             FilterChain filterChain) throws IOException, ServletException {
            // do something 处理request 或response
            System.out.println("MyFilter2.doFilter");
    
            if (servletRequest instanceof HttpServletRequest) {
                System.out.println("  URL:" + ((HttpServletRequest)servletRequest).getRequestURL());
            }
    
            // 调用filter链中的下一个filter
            filterChain.doFilter(servletRequest,servletResponse);
        }
    
        @Override
        public void destroy() {
            System.out.println("MyFilter2.destroy");
        }
    }

**配置类**

package com.example.filter;
    
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class FilterConfig {
    
        @Bean
        public FilterRegistrationBean registrationBean1() {
            FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter1());
            filterRegistrationBean.addUrlPatterns("/*");
    //        filterRegistrationBean.setName("xxx");  //可设置过滤器名字
    
            //过滤器执行顺序。（决定doFilter顺序，不决定init和destroy顺序）
            filterRegistrationBean.setOrder(1);
            return filterRegistrationBean;
        }
    
        @Bean
        public FilterRegistrationBean registrationBean2() {
            FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter2());
            filterRegistrationBean.addUrlPatterns("/*");
    //        filterRegistrationBean.setName("xxx");  //可设置过滤器名字
    
            //过滤器执行顺序（决定doFilter顺序，不决定init和destroy顺序）
            filterRegistrationBean.setOrder(2);
            return filterRegistrationBean;
        }
    }

**执行结果**

> 启动SpringBoot
> 
>     MyFilter2.init
>       过滤器名：myFilter2
>     MyFilter1.init
>       过滤器名：myFilter1
> 
> postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果
> 
>     MyFilter1.doFilter
>       URL:http://localhost:8080/hello/test1
>     MyFilter2.doFilter
>       URL:http://localhost:8080/hello/test1
>     HelloController.test1
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }
> 
> **关闭SpringBoot** 
> 
>     Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'
>     MyFilter2.destroy
>     MyFilter1.destroy
>     2020-09-04 23:26:00.810  INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

**测试结果（配置类setOrder的值调换顺序）**

> 配置类：
> 
>     package com.example.filter;
>     
>     import org.springframework.boot.web.servlet.FilterRegistrationBean;
>     import org.springframework.context.annotation.Bean;
>     import org.springframework.context.annotation.Configuration;
>     
>     @Configuration
>     public class FilterConfig {
>     
>         @Bean
>         public FilterRegistrationBean registrationBean1() {
>             FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter1());
>             filterRegistrationBean.addUrlPatterns("/*");
>     //        filterRegistrationBean.setName("xxx");  //可设置过滤器名字
>     
>             //过滤器执行顺序。（决定doFilter顺序，不决定init和destroy顺序）
>             filterRegistrationBean.setOrder(2);
>             return filterRegistrationBean;
>         }
>     
>         @Bean
>         public FilterRegistrationBean registrationBean2() {
>             FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter2());
>             filterRegistrationBean.addUrlPatterns("/*");
>     //        filterRegistrationBean.setName("xxx");  //可设置过滤器名字
>     
>             //过滤器执行顺序（决定doFilter顺序，不决定init和destroy顺序）
>             filterRegistrationBean.setOrder(1);
>             return filterRegistrationBean;
>         }
>     }

> **测试：** 
> 
> **启动SpringBoot**
> 
>     MyFilter2.init
>       过滤器名：myFilter2
>     MyFilter1.init
>       过滤器名：myFilter1
> 
> **postman访问**：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果
> 
>     MyFilter2.doFilter
>       URL:http://localhost:8080/hello/test1
>     MyFilter1.doFilter
>       URL:http://localhost:8080/hello/test1
>     HelloController.test1
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }
> 
> **关闭SpringBoot**
> 
>     Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'
>     MyFilter2.destroy
>     MyFilter1.destroy
>     2020-09-04 23:26:00.810  INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

# 拦截器 #

**其他网址**

> [Spring Boot 优雅的配置拦截器方式 - GIT猿【边鹏】博客 - OSCHINA][Spring Boot _ - GIT_ - OSCHINA]  
> [Spring Boot拦截器(Interceptor)详解 - 掘金][Spring Boot_Interceptor_ -]

## 简介 ##

**使用场景**

>  *  日志记录：记录请求信息的日志，以便进行信息监控、信息统计、计算PV（Page View）等
>  *  权限检查：如登录检测，进入处理器检测检测是否登录
>  *  性能监控：通过拦截器在进入处理器之前记录开始时间，在处理完后记录结束时间，从而得到该请求的处理时间。（反向代理，如apache也可以自动记录）；
>  *  通用行为：读取cookie得到用户信息并将用户对象放入请求，从而方便后续流程使用，还有如提取Locale、Theme信息等，只要是多个处理器都需要的即可使用拦截器实现。

**Interceptor 的相关方法**

> Spring 中主要通过 HandlerInterceptor 接口来实现请求的拦截，实现 HandlerInterceptor 接口需要实现下面三个方法：
> 
> 1.  **preHandle()** – 在handler执行之前，返回 boolean 值，true 表示继续执行，false 为停止执行并返回。
> 2.  **postHandle()**  – 在handler执行之后, 可以在返回之前对返回的结果进行修改
> 3.  **afterCompletion()** – 在请求完全结束后调用，可以用来统计请求耗时等等

**注意事项**

> **推荐写法**
> 
>  *  实现WebMvcConfigurer接口是官方推荐的
> 
> **不推荐写法**
> 
>  *  实现WebMvcConfigurerAdapter：Spring5.0之后是废弃的。
>  *  继承WebMvcConfigurationSupport：会导致yml的配置失效。原因：WebMvcAutoConfiguration有个条件注解：@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)

## 实例（单拦截器拦截所有） ##

**拦截器类**

>     package com.example.interceptor;
>     
>     import org.springframework.lang.Nullable;
>     import org.springframework.web.servlet.HandlerInterceptor;
>     import org.springframework.web.servlet.ModelAndView;
>     
>     import javax.servlet.http.HttpServletRequest;
>     import javax.servlet.http.HttpServletResponse;
>     
>     public class MyInterceptor implements HandlerInterceptor {
>     
>         @Override
>         public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
>                                  Object handler) throws Exception {
>             System.out.println("MyInterceptor.preHandle");
>             return true;
>         }
>     
>         @Override
>         public void postHandle(HttpServletRequest request, HttpServletResponse response,
>                                Object handler, @Nullable ModelAndView modelAndView) throws Exception {
>             System.out.println("MyInterceptor.postHandle");
>         }
>     
>         @Override
>         public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
>                                     Object handler, @Nullable Exception ex) throws Exception {
>             System.out.println("MyInterceptor.afterCompletion");
>         }
>     }

**配置类**

>     package com.example.interceptor;
>     
>     import org.springframework.context.annotation.Configuration;
>     import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
>     import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
>     
>     @Configuration
>     public class InterceptorConfig implements WebMvcConfigurer {
>     
>         @Override
>         public void addInterceptors(InterceptorRegistry registry) {
>             registry.addInterceptor(new MyInterceptor());
>     //        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/hello/test2");
>         }
>     }

**测试结果**

> **postman访问**：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果：
> 
>     MyInterceptor.preHandle
>     HelloController.test1
>     MyInterceptor.postHandle
>     MyInterceptor.afterCompletion
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

## 实例（单拦截器拦截特定URL） ##

**拦截器类**

**配置类**

>     package com.example.interceptor;
>     
>     import org.springframework.context.annotation.Configuration;
>     import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
>     import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
>     
>     @Configuration
>     public class InterceptorConfig implements WebMvcConfigurer {
>     
>         @Override
>         public void addInterceptors(InterceptorRegistry registry) {
>     //        registry.addInterceptor(new MyInterceptor());
>            registry.addInterceptor(new MyInterceptor()).addPathPatterns("/hello/test2");
>         }
>     }

**测试结果**

> postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果：
> 
>     HelloController.test1
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

## 实例（单拦截器结合注解） ##

使用场景示例：在需要登录验证的Controller的方法上使用注解。当然，也可以直接通过HttpServletRequest获得URI来判断。

**注解类**

>     package com.example.interceptor;
>     
>     import java.lang.annotation.ElementType;
>     import java.lang.annotation.Retention;
>     import java.lang.annotation.RetentionPolicy;
>     import java.lang.annotation.Target;
>     
>     /**
>      * 在需要登录验证的Controller的方法上使用此注解
>      */
>     @Target({ElementType.METHOD})      // 可用在方法名上
>     @Retention(RetentionPolicy.RUNTIME)// 运行时有效
>     public @interface LoginRequired {
>     	
>     }

**拦截器类**

>     package com.example.interceptor;
>     
>     import org.springframework.lang.Nullable;
>     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;
>     import java.lang.reflect.Method;
>     
>     public class MyInterceptor3 implements HandlerInterceptor {
>     
>         @Override
>         public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
>                                  Object handler) throws Exception {
>             System.out.println("MyInterceptor3.preHandle");
>             // 如果不是映射到方法直接通过
>             if (!(handler instanceof HandlerMethod)) {
>                 return true;
>             }
>     
>             // 方法注解级拦截器
>             HandlerMethod handlerMethod = (HandlerMethod) handler;
>             Method method = handlerMethod.getMethod();
>     
>             // 判断接口是否需要登录。也可用method.isAnnotationPresent(LoginRequired.class)
>             LoginRequired methodAnnotation = method.getAnnotation(LoginRequired.class);
>             // 有 @LoginRequired 注解，需要认证
>             if (methodAnnotation != null) {
>                 // 取缓存，SESSION，权限判断等
>                 System.out.println("   权限判断等");
>                 return true;
>             }
>             return true;
>         }
>     
>         @Override
>         public void postHandle(HttpServletRequest request, HttpServletResponse response,
>                                Object handler, @Nullable ModelAndView modelAndView) throws Exception {
>             System.out.println("MyInterceptor3.postHandle");
>         }
>     
>         @Override
>         public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
>                                     Object handler, @Nullable Exception ex) throws Exception {
>             System.out.println("MyInterceptor3.afterCompletion");
>         }
>     }

**拦截器配置**

>     package com.example.interceptor;
>     
>     import org.springframework.context.annotation.Configuration;
>     import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
>     import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
>     
>     @Configuration
>     public class InterceptorConfig implements WebMvcConfigurer {
>     
>         @Override
>         public void addInterceptors(InterceptorRegistry registry) {
>             //这个顺序会决定拦截器执行顺序
>             registry.addInterceptor(new MyInterceptor3());
>     //        registry.addInterceptor(new MyInterceptor2());
>     //        registry.addInterceptor(new MyInterceptor1());
>     //        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/hello/test2");
>         }
>     }

**controller**

>     package com.example.controller;
>     
>     import com.example.entity.User;
>     import com.example.interceptor.LoginRequired;
>     import org.springframework.web.bind.annotation.RequestMapping;
>     import org.springframework.web.bind.annotation.RestController;
>     
>     @RestController
>     @RequestMapping("/hello")
>     public class HelloController {
>     
>         @LoginRequired
>         @RequestMapping("/test1")
>         public User test1(User user) {
>             System.out.println("HelloController.test1");
>             return user;
>         }
>     }

**测试结果**

> **postman访问**：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果
> 
>     MyInterceptor3.preHandle
>        权限判断等
>     HelloController.test1
>     MyInterceptor3.postHandle
>     MyInterceptor3.afterCompletion
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

## 实例（多个拦截器拦截所有） ##

**拦截器1**

>     package com.example.interceptor;
>     
>     import org.springframework.lang.Nullable;
>     import org.springframework.web.servlet.HandlerInterceptor;
>     import org.springframework.web.servlet.ModelAndView;
>     
>     import javax.servlet.http.HttpServletRequest;
>     import javax.servlet.http.HttpServletResponse;
>     
>     public class MyInterceptor1 implements HandlerInterceptor {
>     
>         @Override
>         public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
>                                  Object handler) throws Exception {
>             System.out.println("MyInterceptor1.preHandle");
>             return true;
>         }
>     
>         @Override
>         public void postHandle(HttpServletRequest request, HttpServletResponse response,
>                                Object handler, @Nullable ModelAndView modelAndView) throws Exception {
>             System.out.println("MyInterceptor1.postHandle");
>         }
>     
>         @Override
>         public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
>                                     Object handler, @Nullable Exception ex) throws Exception {
>             System.out.println("MyInterceptor1.afterCompletion");
>         }
>     }

**拦截器2**

>     package com.example.interceptor;
>     
>     import org.springframework.lang.Nullable;
>     import org.springframework.web.servlet.HandlerInterceptor;
>     import org.springframework.web.servlet.ModelAndView;
>     
>     import javax.servlet.http.HttpServletRequest;
>     import javax.servlet.http.HttpServletResponse;
>     
>     public class MyInterceptor2 implements HandlerInterceptor {
>     
>         @Override
>         public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
>                                  Object handler) throws Exception {
>             System.out.println("MyInterceptor2.preHandle");
>             return true;
>         }
>     
>         @Override
>         public void postHandle(HttpServletRequest request, HttpServletResponse response,
>                                Object handler, @Nullable ModelAndView modelAndView) throws Exception {
>             System.out.println("MyInterceptor2.postHandle");
>         }
>     
>         @Override
>         public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
>                                     Object handler, @Nullable Exception ex) throws Exception {
>             System.out.println("MyInterceptor2.afterCompletion");
>         }
>     }

**配置类**

>     package com.example.interceptor;
>     
>     import org.springframework.context.annotation.Configuration;
>     import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
>     import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
>     
>     @Configuration
>     public class InterceptorConfig implements WebMvcConfigurer {
>     
>         @Override
>         public void addInterceptors(InterceptorRegistry registry) {
>             //如果不写.order，则按照先后顺序
>             registry.addInterceptor(new MyInterceptor1()).order(0);
>             registry.addInterceptor(new MyInterceptor2()).order(1);
>         }
>     }

**测试结果**

> postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果
> 
>     MyInterceptor1.preHandle
>     MyInterceptor2.preHandle
>     HelloController.test1
>     MyInterceptor2.postHandle
>     MyInterceptor1.postHandle
>     MyInterceptor2.afterCompletion
>     MyInterceptor1.afterCompletion
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

**配置类（颠倒顺序）**

>     package com.example.interceptor;
>     
>     import org.springframework.context.annotation.Configuration;
>     import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
>     import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
>     
>     @Configuration
>     public class InterceptorConfig implements WebMvcConfigurer {
>     
>         @Override
>         public void addInterceptors(InterceptorRegistry registry) {
>             //如果不写.order，则按照先后顺序
>             registry.addInterceptor(new MyInterceptor2()).order(0);
>             registry.addInterceptor(new MyInterceptor1()).order(1);
>         }
>     }

**测试结果（颠倒顺序后）**

> postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]
> 
> 后端结果
> 
>     MyInterceptor2.preHandle
>     MyInterceptor1.preHandle
>     HelloController.test1
>     MyInterceptor1.postHandle
>     MyInterceptor2.postHandle
>     MyInterceptor1.afterCompletion
>     MyInterceptor2.afterCompletion
> 
> postman结果
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

# 联合实例：过滤/拦截/@ControllerAdvice/AOP #

**实体类**

package com.example.entity;
    
    import lombok.Data;
    
    @Data
    public class User {
        private Integer id;
        private String name;
        private Integer age;
    }

**控制器**

package com.example.controller;
    
    import com.example.entity.User;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/hello")
    public class HelloController {
    
        @RequestMapping("/test1")
        public User test1(User user) {
            System.out.println("HelloController.test1");
            return user;
        }
    }

**过滤器**

package com.example.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import java.io.IOException;
    
    public class MyFilter implements Filter {
        @Override
        public void init(javax.servlet.FilterConfig filterConfig) throws ServletException {
            System.out.println("MyFilter.init");
            System.out.println("  过滤器名：" + filterConfig.getFilterName());
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,
                             FilterChain filterChain) throws IOException, ServletException {
            // do something 处理request 或response
            System.out.println("MyFilter.doFilter");
    
            if (servletRequest instanceof HttpServletRequest) {
                System.out.println("  URL:" + ((HttpServletRequest)servletRequest).getRequestURL());
            }
    
            // 调用filter链中的下一个filter
            filterChain.doFilter(servletRequest,servletResponse);
        }
    
        @Override
        public void destroy() {
            System.out.println("MyFilter.destroy");
        }
    }

**拦截器**

package com.example.interceptor;
    
    import org.springframework.lang.Nullable;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class MyInterceptor implements HandlerInterceptor {
    
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                                 Object handler) throws Exception {
            System.out.println("MyInterceptor.preHandle");
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response,
                               Object handler, @Nullable ModelAndView modelAndView) throws Exception {
            System.out.println("MyInterceptor.postHandle");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
                                    Object handler, @Nullable Exception ex) throws Exception {
            System.out.println("MyInterceptor.afterCompletion");
        }
    }

package com.example.interceptor;
    
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    @Configuration
    public class InterceptorConfig implements WebMvcConfigurer {
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(new MyInterceptor());
        }
    }

**@ControllerAdvice**

package com.example.advice;
    
    import org.springframework.web.bind.annotation.ControllerAdvice;
    import org.springframework.web.bind.annotation.ModelAttribute;
    
    @ControllerAdvice
    public class GlobalControllerAdvice {
        @ModelAttribute
        public void authenticationUser() {
            System.out.println("GlobalControllerAdvice.authenticationUser");
        }
    }

**对@RequestMapping的AOP**

package com.example.aspect;
    
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class RequestMappingAspect {
        @Pointcut("@annotation(org.springframework.web.bind.annotation.RequestMapping)")
        public void pointcut() {
    
        }
    
        @Around("pointcut()")
        public Object around1(ProceedingJoinPoint joinPoint) throws Throwable {
            System.out.println("[RequestMappingAspect.around1]: around before");
            Object object = joinPoint.proceed();
            System.out.println("[RequestMappingAspect.around1]: around after");
    
            return object;
        }
    }

**测试**

> **启动SpringBoot**
> 
>     MyFilter.init
>       过滤器名：myFilter

postman访问：[http://localhost:8080/hello/test1?name=Tony][http_localhost_8080_hello_test1_name_Tony]

> **后端结果**
> 
>     MyFilter.doFilter
>       URL:http://localhost:8080/hello/test1
>     MyInterceptor.preHandle
>     GlobalControllerAdvice.authenticationUser
>     [RequestMappingAspect.around1]: around before
>     HelloController.test1
>     [RequestMappingAspect.around1]: around after
>     MyInterceptor.postHandle
>     MyInterceptor.afterCompletion
> 
> ![70 1][]

> **postman结果**
> 
>     {
>         "id": null,
>         "name": "Tony",
>         "age": null
>     }

> **关闭SpringBoot**
> 
>     Disconnected from the target VM, address: '127.0.0.1:61631', transport: 'socket'
>     MyFilter.destroy
>     2020-09-05 17:49:01.499  INFO 17144 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

[spring boot _hwm_-CSDN]: https://blog.csdn.net/heweimingming/article/details/79993591
[Spring Interceptor vs Filter _ _ ASPIRE]: https://ixyzero.com/blog/archives/3855.html
[SpringAOP_--AOP_ _feiying0canglang_-CSDN]: https://blog.csdn.net/feiying0canglang/article/details/108395605
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NjY0OTA2_size_16_color_FFFFFF_t_70]: /images/20221123/a48b0b69236044cf8c406ac3456a9346.png
[70]: /images/20221123/8403c83ab99946238a18af7ca46dbc37.png
[servlet]: http://www.51gjie.com/javaweb/867.html
[http_localhost_8080_hello_test1_name_Tony]: http://localhost:8080/hello/test1?name=Tony
[Spring Boot _ - GIT_ - OSCHINA]: https://my.oschina.net/bianxin/blog/2876640
[Spring Boot_Interceptor_ -]: https://juejin.im/post/6844904020675559432
[70 1]: /images/20221123/2d27f83bd81b4b949a38154ac1d74121.png