拦截器与过滤器

流程图

拦截器vs过滤器

拦截器是SpringMVC的技术

过滤器的Servlet的技术

先过过滤器，过滤器过完才到DispatcherServlet；

拦截器归属于SpringMVC，只可能拦SpringMVC的东西；

拦截器说白了就是为了增强，可以在请求前进行增强，也可以在请求后进行增强，但是不一定同时在前后都增强。

区别

SpringMVC技术架构图

项目Demo

项目地址

依赖

    <parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.2.7.RELEASE</version></parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency></dependencies>

Interceptor拦截器

package com.test.filtertest.inter;import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** 拦截器** @author: zhangzengxiu* @createDate: 2022/4/22*/
@Component
public class TestInter1 implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("TestInter1 preHandle...");return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("TestInter1 postHandle...");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("TestInter1 afterCompletion...");}
}

Interceptor拦截器要注册

package com.test.filtertest.config;import com.test.filtertest.inter.TestInter1;
import com.test.filtertest.inter.TestInter2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;/*** @author zhangzengxiu* @date 2022/4/22*/
@Configuration
public class WebConfig implements WebMvcConfigurer {@Autowiredprivate TestInter1 testInter1;@Autowiredprivate TestInter2 testInter2;@Overridepublic void addInterceptors(InterceptorRegistry registry) {//默认/** 拦截所有请求registry.addInterceptor(testInter1).addPathPatterns("/**");registry.addInterceptor(testInter2);}
}

拦截顺序

多拦截器拦截顺序取决于registry的注册顺序

package com.test.filtertest.filter;import org.springframework.core.annotation.Order;import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;/*** @author zhangzengxiu* @date 2022/4/22*/
@WebFilter(filterName = "TestFilter1", urlPatterns = "/*")
//@Order(2) //filter这样定义拦截顺序无效，还是会按照类名去拦截
public class TestFilter1 implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {System.out.println("TestFilter1 filter before ...");filterChain.doFilter(servletRequest, servletResponse);System.out.println("TestFilter1 filter after ...");}@Overridepublic void destroy() {}
}

package com.test.config;import com.test.filter.TestFilter1;
import com.test.filter.TestFilter2;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import javax.servlet.Filter;/*** filter过滤器配置** @author: zhangzengxiu* @createDate: 2022/4/24*/
@Configuration
public class FilterConfig {@Beanpublic FilterRegistrationBean testFilter1() {FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();Filter testFilter1 = new TestFilter1();filterRegistrationBean.setFilter(testFilter1);filterRegistrationBean.addUrlPatterns("/*");filterRegistrationBean.setName("testFilter1");filterRegistrationBean.setOrder(2);//指定过滤顺序，数值越小优先级越高return filterRegistrationBean;}@Beanpublic FilterRegistrationBean testFilter2() {FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();Filter testFilter2 = new TestFilter2();filterRegistrationBean.setFilter(testFilter2);filterRegistrationBean.setName("testFilter2");filterRegistrationBean.addUrlPatterns("/*");filterRegistrationBean.setOrder(1);//指定过滤顺序，数值越小优先级越高return filterRegistrationBean;}
}