1.场景

web程序中，对用户请求，经常会对请求进行拦截处理，常用的处理方式如下：

• Filter
• Interceptor
• AOP

在此基于SpringBoot的web程序，进行这三种拦截方式的说明。

2.区别

三种拦截方式的区别如下：

3.请求顺序

基于SpringBoot的web程序，Filter、Interceptor、Aop的请求顺序如下：

Filter -> Interceptor ->AOP -> Controller

image-20210512172914548.png

4.版本

4.1 maven依赖

Filter和Interceptor有spring-boot-starter-web依赖即可：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

AOP依赖的aspectJ需要额外的maven依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
    <version>2.2.9.RELEASE</version>
</dependency>

4.2 测试Controller

package com.wangcp.intercept.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

/**
* 测试类
* @author wangcp
* @date 2021/05/12 15:45
**/
@RestController
@RequestMapping(value = "/my")
public class MyController {

    @GetMapping(value = "/test")
    public Map<String,Object> test(String userName , String age){
        String message = "[Controller Action]：userName=" + userName + "；age=" + age;
        System.out.println(message);
        Map<String,Object> map = new HashMap<>();
        map.put("success",true);
        map.put("message",message);
        return map;
    }

}

5.Filter代码实现

5.1 说明

1.实现接口

实现接口：javax.servlet.Filter

2.核心方法

public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {}

5.2 定义

1.定义Filter

package com.wangcp.intercept.filter;


import javax.servlet.*;
import java.io.IOException;
import java.util.Date;

/**
* 计算执行时间Filter
* @author wangcp
* @date 2021/05/12 15:50
**/
public class TimerFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        long begin = new Date().getTime();
        System.out.println("[Filter-Time]：进入Filter");
        // 执行servlet方法（如拦截请求，不执行servlet，可不执行此方法）
        filterChain.doFilter(servletRequest , servletResponse);
        long end = new Date().getTime();
        System.out.println("[Filter-Time]：结束Filter，共" + (end - begin) + "毫秒");
    }
}

2.配置

package com.wangcp.intercept.filter.config;

import com.wangcp.intercept.filter.TimerFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Arrays;

/**
* filter配置类
* @author wangcp
* @date 2021/05/12 15:54
**/
@Configuration
public class WebFilterConfig {

    @Bean
    public FilterRegistrationBean timerFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        // 设置：实现类
        registrationBean.setFilter(new TimerFilter());
        // 设置：UrlPatterns (要拦截的url)
        registrationBean.setUrlPatterns(Arrays.asList("/*"));
        // 设置：优先级
        registrationBean.setOrder(1);
        return registrationBean;
    }

}

5.3 测试

1.测试请求

http://localhost:8080/my/test?userName=wangcp&age=18

2.输出结果

[Filter-Time]：进入Filter
[Controller Action]：userName=wangcp；age=18
[Filter-Time]：结束Filter，共40毫秒

5.4 配置顺序

// 设置：优先级
registrationBean.setOrder(1);

6.HandlerInterceptor 代码实现

6.1 说明

1.实现接口

实现接口：org.springframework.web.servlet.HandlerInterceptor

2.核心方法

各方法详细介绍可查看： https://blog.csdn.net/weixin_41767154/article/details/84648873

// 调用Controller方法之前
boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception;

// 在当前这个Interceptor的preHandle方法返回值为true的时候才会执行
void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,@Nullable ModelAndView modelAndView) throws Exception;

// 也是需要当前对应的Interceptor的preHandle方法的返回值为true时才会执行
void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,@Nullable Exception ex) throws Exception;

6.2 定义

1.定义Interceptor

package com.wangcp.intercept.interceptor;

import com.alibaba.fastjson.JSONObject;
import org.springframework.stereotype.Component;
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.io.PrintWriter;

/**
* 鉴权拦截器
* @author wangcp
* @date 2021/05/12 16:05
 * https://blog.csdn.net/weixin_41767154/article/details/84648873
**/
@Component
public class AuthInterceptor implements HandlerInterceptor {

    /**
    * 调用Controller方法之前
    * @author wangcp
    * @date 2021/05/12 16:06
     * @param request
     * @param response
     * @param handler
    * @return boolean
    */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("[Interceptor-auth]：进入preHandle");
        if(handler instanceof HandlerMethod){
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            System.out.println("[Interceptor-auth]：访问信息=" + handlerMethod.getShortLogMessage());
            // 获取head鉴权信息
            String sign = request.getHeader("sign");
            if (!"123456".equals(sign)) {
                // 鉴权不通过
                response.setCharacterEncoding("utf-8");
                response.setContentType("application/json; charset=utf-8");
                PrintWriter writer = response.getWriter();
                JSONObject jsonObject = new JSONObject();
                jsonObject.put("success", false);
                jsonObject.put("message", "鉴权失败");
                writer.write(jsonObject.toJSONString());
                writer.flush();
                writer.close();
                System.out.println("[Interceptor-auth]：----------鉴权不通过----------");
                System.out.println("[Interceptor-auth]：结束preHandle");
                return false;
            } else {
                // 鉴权通过
                System.out.println("[Interceptor-auth]：----------鉴权通过----------");
                System.out.println("[Interceptor-auth]：结束preHandle");
                return true;
            }
        }
        System.out.println("[Interceptor-auth]：结束preHandle");
        // 返回true为通过校验，返回false为不通过校验
        return true;
    }

    /**
    * 在当前这个Interceptor的preHandle方法返回值为true的时候才会执行
     * 执行时机：在DispatcherServlet进行视图的渲染之前执行，也就是说在这个方法中你可以对ModelAndView进行操作
    * @author wangcp
    * @date 2021/05/12 16:07
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
    * @return void
    */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("[Interceptor-auth]：postHandle ModelAndView=" + JSONObject.toJSONString(modelAndView));
    }

    /**
     * 也是需要当前对应的Interceptor的preHandle方法的返回值为true时才会执行
     * 执行时机：该方法将在整个请求完成之后，也就是DispatcherServlet渲染了视图执行
     * （这个方法的主要作用是用于清理资源的）
    * @author wangcp
    * @date 2021/05/12 16:07
     * @param request
     * @param response
     * @param handler
     * @param ex
    * @return void
    */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("[Interceptor-auth]：afterCompletion Exception=" + JSONObject.toJSONString(ex));
    }
}

2.配置

package com.wangcp.intercept.interceptor.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
* WEB统一配置
* @author wangcp
* @date 2021/05/12 16:20
**/
@Component
public class GlobalWebMvcConfigurer implements WebMvcConfigurer {

    @Autowired
    private HandlerInterceptor authInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(authInterceptor).addPathPatterns("/**");

        // 支持定义多个PathPattern和excludePathPatterns
//        registry.addInterceptor(authInterceptor).addPathPatterns("/xxx","/**").excludePathPatterns("/yyy","/zzz");
    }
}

6.3 测试

1.正向测试

请求：

http://localhost:8080/my/test?userName=wangcp&age=18
请求head：sign=123456

输出结果：

[Interceptor-auth]：进入preHandle
[Interceptor-auth]：访问信息=com.wangcp.intercept.controller.MyController#test[2 args]
[Interceptor-auth]：----------鉴权通过----------
[Interceptor-auth]：结束preHandle
[Controller Action]：userName=wangcp；age=18
[Interceptor-auth]：postHandle ModelAndView=null
[Interceptor-auth]：afterCompletion Exception=null

请求结果：

{
    "success": true,
    "message": "[Controller Action]：userName=wangcp；age=18"
}

2.逆向测试

请求：

http://localhost:8080/my/test?userName=wangcp&age=18
请求head：sign=8888

输出结果：

[Interceptor-auth]：进入preHandle
[Interceptor-auth]：访问信息=com.wangcp.intercept.controller.MyController#test[2 args]
[Interceptor-auth]：----------鉴权不通过----------
[Interceptor-auth]：结束preHandle

请求结果：

{
    "success": false,
    "message": "鉴权失败"
}

7.AOP代码实现

7.1 说明

相关注解

各注解详细介绍可参考：https://blog.csdn.net/qq_45515432/article/details/104187326

org.aspectj.lang.annotation.Aspect
org.aspectj.lang.annotation.Pointcut
org.aspectj.lang.annotation.Before
org.aspectj.lang.annotation.After
org.aspectj.lang.annotation.Around

7.2 定义

package com.wangcp.intercept.aop;

import com.alibaba.fastjson.JSONObject;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
* AOP实现拦截请求
* @author wangcp
* @date 2021/05/12 16:34
 * https://blog.csdn.net/qq_45515432/article/details/104187326
**/
@Component
@Order(1)
@Aspect
public class LogApp {

    @Pointcut("execution(public * com.wangcp..controller..*(..))")
    public void log() {
        
    }

    @Before("log()")
    public void doBefore(JoinPoint joinPoint) {
        System.out.println("[AOP-log]：Before");
    }

    @After("log()")
    public void doAfter(JoinPoint joinPoint) {
        System.out.println("[AOP-log]：After");
    }

    @Around("log()")
    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("[AOP-log]：Around-进入");
        // 请求参数
        System.out.println("[AOP-log]：Around-请求参数="+ JSONObject.toJSONString(joinPoint.getArgs()));

        // 执行切面方法
        Object object = joinPoint.proceed();

        // 执行结果
        System.out.println("[AOP-log]：Around-执行结果="+ JSONObject.toJSONString(object));
        System.out.println("[AOP-log]：Around-结束");
        return object;
    }
}

7.3 测试

1.测试请求

http://localhost:8080/my/test?userName=wangcp&age=18

2.输出结果

[AOP-log]：Around-进入
[AOP-log]：Around-请求参数=["wangcp","18"]
[AOP-log]：Before
[Controller Action]：userName=wangcp；age=18
[AOP-log]：After
[AOP-log]：Around-执行结果={"success":true,"message":"[Controller Action]：userName=wangcp；age=18"}
[AOP-log]：Around-结束

3.请求结果

{"success":true,"message":"[Controller Action]：userName=wangcp；age=18"}

8.汇总测试

同时打开上述的Filter，Interceptor，AOP，一起来拦截请求。

1.测试请求

http://localhost:8080/my/test?userName=wangcp&age=18
请求head：sign=123456

2.输出结果

[Filter-Time]：进入Filter
[Interceptor-auth]：进入preHandle
[Interceptor-auth]：访问信息=com.wangcp.intercept.controller.MyController#test[2 args]
[Interceptor-auth]：----------鉴权通过----------
[Interceptor-auth]：结束preHandle
[AOP-log]：Around-进入
[AOP-log]：Around-请求参数=["wangcp","18"]
[AOP-log]：Before
[Controller Action]：userName=wangcp；age=18
[AOP-log]：After
[AOP-log]：Around-执行结果={"success":true,"message":"[Controller Action]：userName=wangcp；age=18"}
[AOP-log]：Around-结束
[Interceptor-auth]：postHandle ModelAndView=null
[Interceptor-auth]：afterCompletion Exception=null
[Filter-Time]：结束Filter，共1毫秒

输出顺序与文章开头请求顺序讲解一致。

3.请求结果

{
    "success": true,
    "message": "[Controller Action]：userName=wangcp；age=18"
}