Spring Boot 实现过滤器（Filter）三种常用方式-尧图网络科技

Filter 是 Java Web 原生组件，优先级早于 Interceptor，可拦截所有请求，下面分三种主流实现方式，附完整代码、配置、执行顺序。

一、前置说明

过滤器基于javax.servlet.Filter（Servlet 规范）
Spring Boot 无需手动配置web.xml，注解/注册 Bean即可生效
执行顺序：Filter → DispatcherServlet → Interceptor → Controller

方式一：注解方式（最简，推荐简单场景）

使用@WebFilter+ 启动类开启 Servlet 注解扫描，零配置。

1. 编写自定义过滤器

importjavax.servlet.*;importjavax.servlet.annotation.WebFilter;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importjava.io.IOException;// 拦截所有请求 /*@WebFilter(filterName="MyFilter",urlPatterns="/*")publicclassMyFilterimplementsFilter{// 初始化（容器启动执行一次）@Overridepublicvoidinit(FilterConfigfilterConfig)throwsServletException{System.out.println("过滤器初始化");}// 核心拦截逻辑（每次请求都会执行）@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{HttpServletRequestreq=(HttpServletRequest)request;HttpServletResponseresp=(HttpServletResponse)response;// 放行前逻辑（前置处理）System.out.println("请求地址："+req.getRequestURI());// 放行，执行后续过滤器/接口chain.doFilter(request,response);// 放行后逻辑（后置处理，响应返回客户端前）System.out.println("请求结束");}// 销毁（容器关闭执行一次）@Overridepublicvoiddestroy(){System.out.println("过滤器销毁");}}

2. 启动类开启注解支持

启动类添加@ServletComponentScan，扫描@WebFilter：

importorg.springframework.boot.SpringApplication;importorg.springframework.boot.autoconfigure.SpringBootApplication;importorg.springframework.boot.web.servlet.ServletComponentScan;@SpringBootApplication@ServletComponentScan// 关键注解：扫描 Servlet、Filter、ListenerpublicclassDemoApplication{publicstaticvoidmain(String[]args){SpringApplication.run(DemoApplication.class,args);}}

优缺点

✅ 简单快捷，适合单过滤器、简单项目
❌无法手动指定多个过滤器执行顺序

方式二：注册 FilterRegistrationBean（推荐，可控制顺序）

Spring Boot 官方推荐方式，支持排序、指定拦截路径、禁用原生注解，多过滤器首选。

1. 先写过滤器（普通 Java 类，不加 @WebFilter）

importjavax.servlet.*;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importjava.io.IOException;publicclassOrderFilter1implementsFilter{@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{System.out.println("【过滤器1】执行");chain.doFilter(request,response);System.out.println("【过滤器1】结束");}@Overridepublicvoidinit(FilterConfigfilterConfig){}@Overridepublicvoiddestroy(){}}

publicclassOrderFilter2implementsFilter{@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{System.out.println("【过滤器2】执行");chain.doFilter(request,response);System.out.println("【过滤器2】结束");}@Overridepublicvoidinit(FilterConfigfilterConfig){}@Overridepublicvoiddestroy(){}}

2. 编写配置类，注册过滤器 + 排序

order值越小，优先级越高，越先执行。

importorg.springframework.boot.web.servlet.FilterRegistrationBean;importorg.springframework.context.annotation.Bean;importorg.springframework.context.annotation.Configuration;@ConfigurationpublicclassFilterConfig{@BeanpublicFilterRegistrationBean<OrderFilter1>filter1(){FilterRegistrationBean<OrderFilter1>bean=newFilterRegistrationBean<>();bean.setFilter(newOrderFilter1());bean.addUrlPatterns("/*");// 拦截路径bean.setOrder(1);// 执行顺序：1 > 2returnbean;}@BeanpublicFilterRegistrationBean<OrderFilter2>filter2(){FilterRegistrationBean<OrderFilter2>bean=newFilterRegistrationBean<>();bean.setFilter(newOrderFilter2());bean.addUrlPatterns("/*");bean.setOrder(2);// 顺序靠后returnbean;}}

执行顺序

请求进来：Filter1 → Filter2 → 接口 → Filter2后置 → Filter1后置

常用配置扩展

// 排除指定路径bean.addInitParameter("exclusions","/login,/static/*");// 设置过滤器名称bean.setName("customFilter");

方式三：直接将 Filter 交给 Spring 容器（简单排序）

直接在 Filter 上加@Component，Spring 自动注册为过滤器。

代码示例

importorg.springframework.stereotype.Component;importjavax.servlet.*;importjava.io.IOException;@ComponentpublicclassBeanFilterimplementsFilter{@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{System.out.println("Spring Bean 过滤器执行");chain.doFilter(request,response);}@Overridepublicvoidinit(FilterConfigfilterConfig){}@Overridepublicvoiddestroy(){}}

控制顺序

配合@Order(数值)，数值越小越先执行：

@Component@Order(0)publicclassBeanFilter1implementsFilter{...}@Component@Order(1)publicclassBeanFilter2implementsFilter{...}

优缺点

✅ 写法简洁
❌ 部分场景路径配置不如FilterRegistrationBean灵活

四、常见实战场景示例（跨域、编码）

统一编码过滤器

@ComponentpublicclassEncodingFilterimplementsFilter{@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{request.setCharacterEncoding("UTF-8");response.setContentType("text/html;charset=UTF-8");chain.doFilter(request,response);}}

简单跨域过滤器

@ComponentpublicclassCorsFilterimplementsFilter{@OverridepublicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain)throwsIOException,ServletException{HttpServletResponseresp=(HttpServletResponse)response;resp.setHeader("Access-Control-Allow-Origin","*");resp.setHeader("Access-Control-Allow-Methods","GET,POST,PUT,DELETE");resp.setHeader("Access-Control-Max-Age","3600");resp.setHeader("Access-Control-Allow-Headers","*");chain.doFilter(request,response);}}