Spring Boot 整合Servlet

冷知识，几乎用不到

在spring boot中使用Servlet有两种实现方法；

方法一：

正常创建servlet,然后只用注解@ServletComponentScan

package clc.user.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * ClassName: FirstServlet<br/>
 * Description:spring boot 整合sevlet <br/>
 * date: 2019/4/1 4:07 PM<br/>
 * <p>
 * 正常创建Servlet
 * 可以使用@WebServlet注解实现
 * 在spring boot启动类加注解@ServletComponentScan,会让spring启动时扫描@WebServlet注解并实例化
 *
 * @author chengluchao
 * @since JDK 1.8
 */

@WebServlet(name = "FirstServlet", urlPatterns = "/FirstServlet")
public class FirstServlet extends HttpServlet {

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

对应的启动类：

@SpringBootApplication
@ServletComponentScan
public class UserServiceApplication {

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

----------

方法二：

正常创建Servlet，但不对其进行配置，放到启动类来操作

package clc.user.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * ClassName: SecondServlet<br/>
 * Description:spring boot 整合sevlet <br/>
 * date: 2019/4/1 4:07 PM<br/>
 * <p>
 *
 * @author chengluchao
 *
 * 需要：
 * @Bean public ServletRegistrationBean getServletRegistrationBean() {
 * ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
 * bean.addUrlMappings("SecondServlet");
 * return bean;
 * }
 * @since JDK 1.8
 */

public class SecondServlet extends HttpServlet {

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

@SpringBootApplication
public class UserServiceApplication2 {

    @Bean
    public ServletRegistrationBean getServletRegistrationBean() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
        bean.addUrlMappings("/SecondServlet");
        return bean;
    }

    public static void main(String[] args) {
        SpringApplication.run(UserServiceApplication2.class, args);
    }
}