springboot整合servlet两种方式

前言：

           springboot与servlet整合的两种方式，整合步骤如下：

springboot整合servlet方式一：

项目结构：

pom.xml:

    4.0.0

    com.lucifer.springboot
    springboot-servlet
    0.0.1-SNAPSHOT
    jar

    springboot-servlet
    Demo project for Spring Boot

    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.5.RELEASE
         
    

    
        UTF-8
        UTF-8
        1.8
    

    
        
            org.springframework.boot
            spring-boot-starter
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

SpringbootServletApplication：

package com.lucifer.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;


/**
 * @ServletComponentScan
 * 在springboot启动时会扫描@WebServlet，并将该类实例化
 */
@SpringBootApplication
@ServletComponentScan
public class SpringbootServletApplication {

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

FirstServet：

启动项目，浏览器输入localhost：8080/first，

ps:整合过程中新手很容易遇坑的地方：原本我的项目结构是这样的，如下图：

这时候启动项目，控制台无报错，浏览器输入地址，404，原因就是因为com.lucifer.springboot.servlet这个包没有扫描到。

 那百度了，按照百度查到的资料，加了扫描包的注解，没用，效果依然凉凉。

因此这里就把启动类放在com.lucifer.springboot包下，FirstServet就包在子包com.lucifer.springboot.servlet下，启动类的扫描默认是扫描与该启动类同包以及其子包下的类。

 

springboot整合servlet方式二：

项目结构：

SecondServlet：

package com.lucifer.springboot.servlet;

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

/**
 * @author: Lucifer
 * @create: 2018-09-19 14:39
 * @description:
 **/
public class SecondServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        resp.getWriter().append("springboot整合servlet成功");
    }
}

SpringbootServletApplication：

package com.lucifer.springboot;

import com.lucifer.springboot.servlet.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;



@SpringBootApplication
public class SpringbootServletApplication {

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

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

}