idea将maven项目改成Spring boot项目的方法步骤

<!-- 这个parent是springboot的父级依赖，
  它提供相关的starter的maven管理以及版本号管理，还有相关maven插件的公共配置 -->
<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.2.4.RELEASE</version>
  <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependencies>
  <!-- 这是springboot的核心starter，它将完成起步依赖，自动配置，日志，YAML配置等功能 -->
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
  </dependency>
  <!-- 测试依赖 -->
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    <exclusions>
      <exclusion>
        <groupId>org.junit.vintage</groupId>
        <artifactId>junit-vintage-engine</artifactId>
      </exclusion>
    </exclusions>
  </dependency>
</dependencies>

<properties>
  <!-- 指定jdk版本 -->
  <java.version>1.8</java.version>
  <!-- druid连接池版本 -->
  <druid.version>1.1.17</druid.version>
</properties>

<dependencies>
  <!-- alibaba开发的druid连接池 -->
  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <!-- 对应properties中的<druid.version> -->
    <version>${druid.version}</version>
  </dependency>
</dependencies>

<!-- spring boot打包插件，主要将spring boot应用打包成jar文件或者war文件 -->
<build>
  <plugins>
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
    </plugin>
  </plugins>
</build>

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

public static void main(String[] args) {
  //SpringApplication的run方法返回一个上下文的容器实例
  ApplicationContext context = SpringApplication.run(TestApplication.class, args);
  //从容器获取bean对象
  UserService service = context.getBean(UserServiceImpl.class);
  service.say();
}

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Configuration
public @interface SpringBootConfiguration {
  @AliasFor(
    annotation = Configuration.class
  )
  boolean proxyBeanMethods() default true;
}

@SpringbootApplication
@MapperScan({"edu.nf.ch01.user.dao", "edu.nf.ch01.product.dao"})
public class TestApplication(){
  public static void main(String[] args){
    SpringApplication.run(TestApplication.class, args);
  }
}

@SpringBootTest
public class UsersTest(){
  
  @AutoWired
  private UserService service;
  
  @Test
  void testUser(){
    ...
  }
}