Servlet

1、创建servlet

（1）创建自定义类

• 并且使用注解@WebServlet匹配路径

  @WebServlet(urlPatterns = "/my") //匹配路径
  public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("我是自定义的");
    }
  }

  （2）使用@ServletComponentScan添加servlet包扫描 ```java @ServletComponentScan(basePackages = “com.daijunyi.springbootthymeleaftest”) @SpringBootApplication public class SpringBootThymeleafTestApplication {

  public static void main(String[] args) {

    SpringApplication.run(SpringBootThymeleafTestApplication.class, args);
  

  }

}

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## 2、Filter过滤器
也需要先添加一个 包扫描@ServletComponentScan<br />（1）创建过滤器

- urlPatterns中匹配路径需要用*不能用** **是spring中使用的
```java
@Slf4j
@WebFilter(urlPatterns = {"/css/*"})
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("MyFilter初始化");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        log.info("doFilter");
    }

    @Override
    public void destroy() {
        log.info("myFilter销毁");
    }
}

3、监听器

• @ServletComponentScan+@WebListener+实现ServletContextListener接口

  @Slf4j
  @WebListener
  public class MyServletContextListener implements ServletContextListener {
  
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        log.info("项目启动");
    }
  
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        log.info("项目结束");
    }
  }
  

  4、另外的方式注册到容器里，RegisterBean方式

  @Configuration
  public class MyConfig {
  
    @Bean
    public ServletRegistrationBean myServlet(){
        MyServlet myServlet = new MyServlet();
        return new ServletRegistrationBean(myServlet,"/my");
    }
  
    @Bean
    public FilterRegistrationBean myFilter(){
        MyFilter myFilter = new MyFilter();
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(myFilter);
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/css/*"));
        return filterRegistrationBean;
    }
  
    @Bean
    public ServletListenerRegistrationBean myListener(){
        MyServletContextListener myServletContextListener = new MyServletContextListener();
        return new ServletListenerRegistrationBean(myServletContextListener);
    }
  }