servlet三大组件包括：Servlet本身、Filter过滤器、Listener监听器。 **1. 实现过滤器接口Filter** ```java public class CustomFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { servletRequest.setCharacterEncoding("UTF-8"); servletResponse.setCharacterEncoding("UTF-8"); servletResponse.setContentType("text/html;charset=UTF-8"); System.out.println("CustomFilter-> 过滤器执行了"); // 放行 filterChain.doFilter(servletRequest, servletResponse); } @Override public void destroy() { } } ``` **2. 注册过滤器** ```java @Configuration public class CustomServerConfig{ @Bean public FilterRegistrationBean filterRegistrationBean() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); //安装过滤器 filterRegistrationBean.setFilter(new CustomFilter()); //对下面这些请求进行拦截并过滤 filterRegistrationBean.setUrlPatterns(Arrays.asList("/", "/index", "/myServlet")); return filterRegistrationBean; } } ```