springboot整合Servlet

Posted 2021-11-29 wangshuang123

一.整合servlet

1.通过注解扫描完成Servlet组件的注解

1.1 编写servlet

/**
 * SpringBoot整合servlet方式一
 * 以往实在web.xml配置
 * <servlet>
 * <servlet-name>FirstServlet</servlet-name>
 * <servlet-class>com.demo.servlet.FirstServlet</servlet-class>
 * </servlet>
 * <p>
 * <sevlet-mapping>
 * <servlet-name>FirstServlet</servlet-name>
 * <url-patter>/first</url-patter>
 * </sevlet-mapping>
 */
//注意继承的是 import javax.servlet.http.HttpServlet;
@WebServlet(name = "FirstServlet", urlPatterns = "/first")
public class FirstServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       System.out.println("FirstServlet........................");
    }
}

1.2 编写启动类

/**
 * springboot整合servlet方式一
 */
@SpringBootApplication
@ServletComponentScan //在springboot启动时会扫描@WebServlet注解，并将该类实例化
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class,args);
    }
}

1.3启动 运行main方法  在浏览器输入http://localhost:8080/ifrst 返回控制台

2.通过方法完成servlet组件的注解

2.1 编写servlet

/**
 * springboot整合servlet方式二
 */
public class SecondServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet...........");

    }
}

2.2编写启动器

/**
 * springboot整合servlet方式二
 */
@SpringBootApplication
public class App2 {
    public static void main(String[] args) {
        SpringApplication.run(App2.class,args);
    }

    /**
     * ServletRegistrationBean是注册servlet的对象
     *
     * @return
     */
    @Bean
    public ServletRegistrationBean getServletRegistrationBean() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
        bean.addUrlMappings("/second");
        return bean;
    }
}

以下如上

小结： springboot整合servlet有两种方式：

1.注解：@WebServlet @SpringBootApplication @ServletComponentScan

2.方法：@Application ServletRegisterBean addUrlMapping @Bean