使用@Configuration编写自定义配置类

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>www.tszr</groupId>
    <artifactId>chapter021</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

package com.itheima.dao;

public class MyService {

}

package com.itheima.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.itheima.dao.MyService;

@Configuration
public class MyConfig {
    
    @Bean
    public MyService myService() {
        return new MyService();
    }
}

package com.itheima;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
//import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
//@ImportResource("classpath:beans.xml")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

package com.itheima;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;

import com.itheima.domain.Person;
import com.itheima.config.MyPropertiesConfig;

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class ApplicationTest {
    
    @Autowired
    private ApplicationContext applicationContext;
    
    @Test
    public void ioTest() {
        System.out.println("spring容器是否包含了我用Configuration和Bean设置的配置对象呢？");
        System.out.println(applicationContext.containsBean("myService"));
    }
}