Spring Boot 整合Web三大基础组件

小半 • 2022年5月26日上午11:49 • 后端开发 • 阅读 171

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🌟 一、Web三大基础组件

Servlet
Listener
Filter

🌟🌟 1.1、编写MyServlet

@WebServlet(urlPatterns = "/hello")//注解非常重要
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("Servlet");
    }
}

🌟🌟 1.2、编写MyFilter

@WebFilter(urlPatterns = "/*")//拦截所有请求
public class WebFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("WebFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        System.out.println("destroy");
    }
}

🌟🌟 1.3、编写MyListener

@WebListener()
public class WebListener extends RequestContextListener {
    @Override//请求初始化
    public void requestInitialized(ServletRequestEvent requestEvent) {
        System.out.println("requestInitialized");
    }

    @Override//请求销毁
    public void requestDestroyed(ServletRequestEvent requestEvent) {
        System.out.println("requestDestroyed");
    }
}

拥有这三个类显然是不够的，必须要将这几个类都扫描进容器中，否则不起任何作用，需要一个非常重要的注解@ServletComponentScan加在启动类的上面，其中填入Web组件的目录包的位置，就可以正常使用

@SpringBootApplication
@ServletComponentScan("com.dong.webcomponent")
public class WebComponentApplication {

    public static void main(String[] args) {
        SpringApplication.run(WebComponentApplication.class, args);
    }

}