一、@WebFilter注解方式

使用@WebFilter注解为声明当前类为filter，第一个参数为该filter起一个名字，第二个参数为说明要拦截的请求地址，当前类需要实现Filter接口，里面有三个方法，分别为过滤器初始化、过滤方法和过滤器销毁。

@Slf4j@WebFilter(filterName = "myFilter1", urlPatterns = "/*")public class MyFilter1 implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { log.info(filterConfig.getFilterName() + " init"); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) { log.info("myFilter1 begin"); try {  log.info("业务方法执行");  chain.doFilter(request, response); } catch (Exception e) {  log.error("error!", e); } log.info("myFilter1 end"); } @Override public void destroy() { }}

启动类添加@ServletComponentScan注解，@ServletComponentScan注解所扫描的包路径必须包含该Filter，代码如下：

@SpringBootApplication@ServletComponentScan(basePackages = "com.example.demo.filter")public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); }}

二、@Bean注解方式

新建MyFilter2.java类，不要加注解@WebFilter，代码如下：

@Slf4jpublic class MyFilter2 implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { log.info(filterConfig.getFilterName() + " init"); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) { log.info("myFilter2 begin"); try {  log.info("业务方法执行");  chain.doFilter(request, response); } catch (Exception e) {  log.error("error!", e); } log.info("myFilter2 end"); } @Override public void destroy() { }}

新建配置类WebConfig.java，配置bean，代码如下：

@Configurationpublic class WebConfig { @Bean public FilterRegistrationBean testFilterRegistration() { FilterRegistrationBean registration = new FilterRegistrationBean(new MyFilter2()); registration.addUrlPatterns("/test"); // registration.setName("myFilter2"); return registration; }}

三、查看运行效果

项目启动后浏览器访问http://localhost:8080/test，可以看到过滤器已生效，后台打印日志如下：

[nio-8080-exec-1] com.example.demo.filter.MyFilter1 : myFilter1 begin[nio-8080-exec-1] com.example.demo.filter.MyFilter1 : 业务方法执行[nio-8080-exec-1] com.example.demo.filter.MyFilter1 : myFilter1 end