自定义 Spring Boot Starter

1. 命名规范

• 官方的命名方式：spring-boot-starter-xxx
• 第三方命名方式：xxx-spring-boot-starter

2. 功能开发

2.1. 引入基础依赖

pom.xml

<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>
    <optional>true</optional>
</dependency>

2.2. 编写配置信息类

import cn.wanyj.component.dcc.types.common.Constants;
import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "wanyj.component.dcc", ignoreInvalidFields = true)
public class DynamicConfigCenterAutoConfigProperties {

    private String system;

    public String getFinalAttributeName(String attributeName) {
        return this.system + Constants.UNDERLINE + attributeName;
    }

    public String getSystem() {
        return system;
    }

    public void setSystem(String system) {
        this.system = system;
    }
}

这样你就可以在 yml 文件中配置了：

application.yml

wanyj:
  component:
    dcc:
      system: test

2.3. 完成业务逻辑，编写自动配置类

import cn.wanyj.component.dcc.domain.entity.AttributeEntity;
import cn.wanyj.component.dcc.domain.service.DynamicConfigCenterService;
import cn.wanyj.component.dcc.domain.service.DynamicConfigCenterServiceImpl;
import cn.wanyj.component.dcc.listener.DynamicConfigCenterAdjustListener;
import cn.wanyj.component.dcc.types.common.Constants;
import org.redisson.api.RTopic;
import org.redisson.api.RedissonClient;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties(value = DynamicConfigCenterAutoConfigProperties.class)
public class DynamicConfigCenterRegisterAutoConfig {

    @Bean
    public DynamicConfigCenterService dynamicConfigCenterService(
            DynamicConfigCenterAutoConfigProperties properties,
            RedissonClient redissonClient) {
        return new DynamicConfigCenterServiceImpl(properties, redissonClient);
    }

    @Bean
    public DynamicConfigCenterAdjustListener dynamicConfigCenterAdjustListener(
            DynamicConfigCenterService dynamicConfigCenterService) {
        return new DynamicConfigCenterAdjustListener(dynamicConfigCenterService);
    }

    @Bean
    public RTopic dynamicConfigCenterRedisTopic(
            DynamicConfigCenterAutoConfigProperties properties,
            RedissonClient redissonClient,
            DynamicConfigCenterAdjustListener dynamicConfigCenterAdjustListener) {
        RTopic topic = redissonClient.getTopic(Constants.getTopic(properties.getSystem()));
        topic.addListener(AttributeEntity.class, dynamicConfigCenterAdjustListener);
        return topic;
    }
}

2.4. 使 starter 生效

方式一：注解启动

你需要自定义一个启动注解：

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({DynamicConfigCenterRegisterAutoConfig.class})
public @interface EnableDCC {
}

然后使用时需要在启动类添加这个注解：

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

方式二：自动生效

• 通过 SpringBoot 的 SPI 的机制来去加载我们的 Starter
• 需要创建 resource/META-INF/spring.factories 文件
• key 为 org.springframework.boot.autoconfigure.EnableAutoConfiguration
• value 为自动配置类的全限定名（记得去除前后的空格，否则会不生效）

spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=cn.wanyj.component.dcc.config.DynamicConfigCenterRegisterAutoConfig

注意

在 Spring Boot 3+ 版本完全移除了 spring.factories 的方式，需要更改目录结构为：

resource/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

org.springframework.boot.autoconfigure.AutoConfiguration.imports

cn.wanyj.component.dcc.config.DynamicConfigCenterRegisterAutoConfig