一、 編寫starter

二、編寫測試類

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新建springboot專案，刪掉測試檔案，pom裡，只保留3個（自動配置，自動配置處理用來在yml提示），去掉build章節

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

        </dependency>

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

    </dependencies>

編寫HelloProperties

@ConfigurationProperties(prefix = "hello")
public class HelloProperties {
    private String name = "anon";
    private String address = "unname address";

    
 
public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "HelloProperties{" +
                "name='" + name + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

編寫自動配置類HelloServiceAutoConfiguration,

註解匯入上一個配置檔案，注意構造器注入屬性

@Configuration
@EnableConfigurationProperties(HelloProperties.class)
public class HelloServiceAutoConfiguration {

   private HelloProperties helloProperties;

    public HelloServiceAutoConfiguration(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }

    @Bean
    @ConditionalOnMissingBean
    public HelloService helloService(){
        return  new HelloService(helloProperties.getName(),helloProperties.getAddress());
    }
}

編寫業務方法HelloService，注意構造器

public class HelloService {

    private String  name;
    private String address;

    public HelloService(String name, String address) {
        this.name = name;
        this.address = address;
    }

    public String sayHello(){
        return "你好，我i是"+name+"，來自"+address;
    }
}

在resources裡，建立META-INF/spring.factories 檔案，讓springboot自動掃描啟動類

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  cn.taotao.config.HelloServiceAutoConfiguration

然後maven install到本地倉庫

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建立測試檔案 ，新建工程demo

新建測試類

    @Autowired
    private HelloService helloService;

    @Test
    void hello(){
        System.out.println("helloService.sayHello() = " + helloService.sayHello());
    }

可以在application.yml 中測試注入的值