一文详解Java拦截器与过滤器的使用一文详解Java拦截器与过滤器的

流程图
拦截器vs过滤器

区别

SpringMVC技术架构图

项目Demo

依赖

Interceptor拦截器

Filter过滤器

1、多Filter不指定过滤顺序

流程图

文章图片

拦截器vs过滤器 【一文详解Java拦截器与过滤器的使用】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

文章图片

SpringMVC技术架构图

文章图片

项目Demo 项目地址

文章图片

依赖

org.springframework.bootspring-boot-starter-parent2.2.7.RELEASEorg.springframework.bootspring-boot-starter-web

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 */@Componentpublic 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 */@Configurationpublic 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

Filter过滤器
1、多Filter不指定过滤顺序

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() {}}

加了@WebFilter注解的过滤器要生效，需要在启动类上加一个注解@ServletComponentScan
2、多Filter指定过滤顺序
如果要设置过滤顺序的话，在Filter上添加@Order 不会生效，还是会默认根据Filter过滤器的类名去进行过滤。
如果想要指定拦截顺序，需要添加一个配置类，通过设置Order的值去设置过滤顺序，Order数值越小优先级越高

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 */@Configurationpublic 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; }}

1、同时原本Filter过滤器上的@WebFilter(filterName = “TestFilter1”, urlPatterns = “/*”)
这个注解最好去掉，否则bean重复会报错，要么bean名称不要重复，换个名称。但是不去掉的话@ServletComponentScan也要被保留，最好统一格式，只使用config配置。
2、启动类上的@ServletComponentScan 注解也不需要了，可以去掉了，因为不用扫描@WebFilter注解了。但是如果@WebFilter还保留了，那么就不能去掉了。不然加了@WebFilter的过滤器就不会生效了，因为没扫到。