在Spring Boot中，创建一个自定义starter可以简化特定功能或组件的配置过程，让其他项目能够轻松地重用这些功能。
这里我们以自定义一个xxl-job的starter为例，介绍下如何简化配置。
添加依赖
<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><!-- 其他需要的依赖 -->
</dependencies>
实现自动配置
import org.springframework.boot.context.properties.ConfigurationProperties;/*** */
@ConfigurationProperties(prefix = XxlJobProperties.PREFIX)
public class XxlJobProperties {public static final String PREFIX = "spring.xxl.job";private boolean enabled;private String adminAddresses;private String accessToken;private String appName;private String ip;private int port;private String logPath;private int logRetentionDays = 30;//getter setter
}
接下来定义Configuration，并且在其中创建需要的bean：
import com.xxl.job.core.executor.impl.XxlJobSpringExecutor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** */
@Configuration
@EnableConfigurationProperties(XxlJobProperties.class)
public class XxlJobConfiguration {private static final Logger logger = LoggerFactory.getLogger(XxlJobConfiguration.class);@Autowiredprivate XxlJobProperties properties;@Bean@ConditionalOnMissingBean@ConditionalOnProperty(prefix = XxlJobProperties.PREFIX, value = "enabled", havingValue = "true")public XxlJobSpringExecutor xxlJobExecutor() {logger.info(">>>>>>>>>>> xxl-job config init.");XxlJobSpringExecutor xxlJobSpringExecutor = new XxlJobSpringExecutor();xxlJobSpringExecutor.setAdminAddresses(properties.getAdminAddresses());xxlJobSpringExecutor.setAppname(properties.getAppName());xxlJobSpringExecutor.setIp(properties.getIp());xxlJobSpringExecutor.setPort(properties.getPort());xxlJobSpringExecutor.setAccessToken(properties.getAccessToken());xxlJobSpringExecutor.setLogPath(properties.getLogPath());xxlJobSpringExecutor.setLogRetentionDays(properties.getLogRetentionDays());return xxlJobSpringExecutor;}
} 这里面用@Bean 注解声明了一个bean，并且使用@ConditionalOnMissingBean类指定这个bean的创建条件，即在确实的时候创建。
@ConditionalOnProperty(prefix = XxlJobProperties.PREFIX, value = "enabled", havingValue = "true")约定了当我们配置了spring.xxl.job.enable=true的时候才会生效。
在你的starter项目的src/main/resources下，创建META-INF/spring目录，并且创建一个
org.springframework.boot.autoconfigure.AutoConfiguration.imports文件，内容如下：
cn.hollis.nft.turbo.job.config.XxlJobConfiguration以上就定义好了一个starter，只需要在需要的地方引入，并且配置上相应的配置项就行了，配置项内容就是我们定义在XxlJobProperties中的。
