一、使用注解方式实现

1、使用Servlet3注解过滤器

@WebFilter(urlPatterns = "/*")
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("进入Filter过滤器。。");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {

    }
}

2、在main方法添加注解

@ServletComponentScan(basePackages = {"com.example.springboot.servlet","com.example.springboot.filter"})

二、通过SpringBoot配置类实现

1、编写一个普通servlet类

public class HeFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("he filter 进入Filter过滤器。。");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {

    }
}

2、编写一个springboot配置类

@Bean
    public FilterRegistrationBean heFilterRegistrationBean() {
        FilterRegistrationBean registration = new FilterRegistrationBean(new HeFilter());
        registration.addUrlPatterns("/*");
        return registration;
    }