I think that Spring's web application architecture can be significantly simplified if it were to provided tools and a reference architecture that leveraged the Spring component and configuration model from top to bottom. Embedding and unifying the configuration of those common web container services within a Spring Container bootstrapped from a simple main() method.我认为，如果要提供从上到下充分利用Spring组件和配置模型的工具和参考体系结构，则可以大大简化Spring的Web应用程序体系结构。在通过简单main（）方法引导的Spring容器中嵌入和统一那些通用Web容器服务的配置。

Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run".// 通过Spring Boot可以轻松的创建独立的、生产级别的基于Spring 生态下的应用，你只需要运行即可。We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need minimal Spring configuration.//对于Spring平台和第三方库，我们提供了一个固化的视图，这个视图可以让我们在构建应用是减少很多麻烦。大部分spring boot应用只需要最小的Spring 配置即可。

  <dependency>      <groupId>org.springframework</groupId>      <artifactId>spring-beans</artifactId>      <version>5.2.5.RELEASE</version>  </dependency>  <dependency>      <groupId>commons-logging</groupId>      <artifactId>commons-logging</artifactId>      <version>1.2</version>  </dependency>

  spring-context  spring-context-support  spring-core  spring-expression  spring-web  spring-webmvc

  <context-param><!--配置上下文配置路径-->      <param-name>contextConfigLocation</param-name>      <param-value>classpath:applicationContext.xml</param-value>  </context-param>  <!--配置监听器-->  <listener>      <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  </listener>  <listener>      <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>  </listener>  <!--配置Spring MVC的请求拦截-->  <servlet>      <servlet-name>springmvc</servlet-name>      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>      <init-param>          <param-name>contextConfigLocation</param-name>          <param-value>classpath:dispatcher-servlet.xml</param-value>      </init-param>  </servlet>  <servlet-mapping>      <servlet-name>springmvc</servlet-name>      <url-pattern>/</url-patter>  </servlet-mapping>

  <?xml version="1.0" encoding="UTF-8"?>  <beans xmlns="http://www.springframework.org/schema/beans"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xmlns:context="http://www.springframework.org/schema/context"         xmlns:mvc="http://www.springframework.org/schema/mvc"         xmlns:aop="http://www.springframework.org/schema/aop"         xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd         http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd         http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">    <!-- 扫描 controller -->  <context:component-scan base-package="com.gupaoedu.controller" />  <!--开启注解驱动-->  <mvc:annotation-driven/>  <!-- 定义视图解析器 -->  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">      <property name="prefix" value="/"/>      <property name="suffix" value=".jsp"/>  </bean>

  @Controller  public class HelloController {        @RequestMapping(method = RequestMethod.GET,path = "/index")      public String index(Model model){          model.addAttribute("key","Hello Gupao");          return "index";      }  }

  <%@ page language="java" contentType="text/html; charset=utf-8"           pageEncoding="utf-8" isELIgnored="false" %>  ${key}

<dependency>    <groupId>mysql</groupId>    <artifactId>mysql-connector-java</artifactId></dependency><dependency>    <groupId>org.mybatis.spring.boot</groupId>    <artifactId>mybatis-spring-boot-starter</artifactId>    <version>2.1.2</version></dependency><dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-thymeleaf</artifactId></dependency>

DROP TABLE IF EXISTS `t_user`;CREATE TABLE `t_user` (  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,  `name` varchar(20) DEFAULT NULL,  `address` varchar(80) DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=latin1;

spring:  datasource:    url: jdbc:mysql://192.168.13.106:3306/test_springboot    username: root    password: root    driver-class-name: com.mysql.cj.jdbc.Driver

public class User {    private int id;    private String name;    private String address;}

//@Repository可以支持在你的持久层作为一个标记，可以去自动处理数据库操作产生的异常@Repository@Mapperpublic interface UserMapper {
    User findById(int id);    List<User> list();    int insert(User user);    int delete(int id);    int update(User user);}

<?xml version="1.0" encoding="utf-8" ?><!DOCTYPE mapper PUBLIC        "-//mybatis.org//DTD com.example.Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.example.demo.mapper.UserMapper">    <resultMap id="resultMap" type="com.example.demo.entity.User">        <id property="id" column="id"/>        <result property="name" column="name"/>        <result property="address" column="address"/>    </resultMap>
    <select id="findById" resultMap="resultMap" parameterType="java.lang.Integer">        select * from t_user where id=#{id}    </select>    <select id="list" resultMap="resultMap">        select * from t_user    </select>    <insert id="insert" parameterType="com.example.demo.entity.User" keyProperty="id" useGeneratedKeys="true">        insert into t_user(name,address) values(#{name,jdbcType=VARCHAR},#{address,jdbcType=VARCHAR})    </insert>    <delete id="delete" parameterType="java.lang.Integer">        delete from t_user where id=#{id}    </delete>    <update id="update" parameterType="com.example.demo.entity.User">        update t_user set name=#{name,jdbcType=VARCHAR},address=#{address,jdbcType=VARCHAR} where id=#{id,jdbcType=INTEGER}    </update></mapper>

public interface IUserService {
    User findById(int id);    List<User> list();    int insert(User user);    int delete(int id);    int update(User user);}
@Servicepublic class UserServiceImpl implements IUserService {    @Autowired    private UserMapper userMapper;}

@RestControllerpublic class Controller {
    @Autowired    private IUserService userService;
    @GetMapping("/user/{id}")    public User user(@PathVariable("id") int id){        return userService.findById(id);    }
    @GetMapping("/users")    public List<User> users(){        return userService.list();    }
    @PostMapping("/user")    public String insertUser(User user){        int row=userService.insert(user);        return row>0?"SUCCESS":"FAILED";    }
    @PutMapping("/user")    public String updateUser(User user){        int row=userService.update(user);        return row>0?"SUCCESS":"FAILED";    }    @DeleteMapping("/user/{id}")    public String deleteUser(@PathVariable("id") int id){        return userService.delete(id)>0?"SUCCESS":"FAILED";    }
}

  @MapperScan("com.example.demo.mapper")

  mybatis:    mapper-locations: classpath:*Mapper.xml

  @RestController  class HelloController {        @GetMapping("/hello")      String hello(){          return "Hello World";      }  }

  spring run hello.groovy -- --server.port=9000

    @RestController    class HelloController {            @GetMapping("/hello")        String hello(){            return "Hello World";        }    }

    spring run hello.groovy -- --server.port=9000