springboot学习(六): 创建自定义的springboot starter

缺乏、安全感 2022-05-10 00:26 203阅读 0赞

# 说明 #

在学习中，希望能创建自己的依赖，让springboot通过<dependency>引用。springboot提供了starter来引用，所以通过创建自定义的starter来实现。有关springboot starter的知识详见[Spring Boot Starters][]

# 正文 #

创建自定义的starter，有两个重要的部分，一个是resources/META-INF/spring.factories文件，在springboot启动时通过扫描该文件来自动加载配置类。另一个是\*\*AutoConfigure类，这个类就是自动配置类，在springboot启动时被自动加载配置。  
在本文中，通过创建一个rediscofig starter来实现redis的配置。

## 1.创建Maven项目 ##

引入依赖

<dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-configuration-processor</artifactId>
           <version>2.0.3.RELEASE</version>
           <optional>true</optional>
    </dependency>
    <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-autoconfigure</artifactId>
           <version>2.0.3.RELEASE</version>
    </dependency>

spring-boot-configuration-processor这个依赖可以为配置属性生成元数据，IDE可以自动感知。  
spring-boot-autoconfigure这个依赖可以允许我们使用适当的注释来创建配置类。

## 2.创建RedisProperties ##

@ConfigurationProperties(prefix = "redis.msg")
    public class RedisProperties {
    
        private String host;
    
        private int port;
    
        private int timeout;
    
    	// Getters + Setters
     }

## 3.创建RedisConfig ##

public class RedisConfig {
    
        private static final Logger logger = LoggerFactory.getLogger(RedisConfig.class);
    
        private RedisProperties redisProperties;
    
        public RedisConfig(){}
    
        public RedisConfig(RedisProperties redisProperties){
            this.redisProperties = redisProperties;
        }
    
        @PostConstruct
        private void init(){
            logger.info(String.format("Init Config -- host : %s, port : %d, timeout : %d %n",redisProperties.getHost(),redisProperties.getPort(),redisProperties.getTimeout()));
        }
    }

## 4.创建RedisAutoConfigure ##

@Configuration
    @ConditionalOnClass(RedisConfig.class)
    @EnableConfigurationProperties(RedisProperties.class)
    public class RedisAutoConfigure {
    
        @Autowired
        private RedisProperties redisProperties;
    
        @Bean
        @ConditionalOnMissingBean
        public RedisConfig redisConfig(){
            return new RedisConfig(redisProperties);
        }
    
    }

有关注解：

@ConditionalOnClass       当在classpath发现指定类时进行自动配置
    @ConditionalOnMissingBean 当spring context不存在该bean时进行配置
    @ConditionalOnProperty    当指定的属性有指定的值使进行配置

## 5.创建spring.factories ##

在resources目录下创建META-INF目录，在该目录下创建文件

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.wds.redis.RedisAutoConfigure

## 6.发布引用 ##

使用mvn命令安装到本地的maven仓库

mvn clean install

新建一个springboot项目引入依赖

<dependency>
    	<groupId>com.wds</groupId>
    	<artifactId>redis.config.starter</artifactId>
    	<version>1.0.0</version>
    </dependency>

源码地址：[https://github.com/Edenwds/springboot\_study/tree/master/build\_starter][https_github.com_Edenwds_springboot_study_tree_master_build_starter]  
参考资料：  
[https://www.nosuchfield.com/2017/10/15/Spring-Boot-Starters/][Spring Boot Starters]  
[https://www.cnblogs.com/yuansc/p/9088212.html][https_www.cnblogs.com_yuansc_p_9088212.html]  
[https://g00glen00b.be/writing-spring-boot-starter/][https_g00glen00b.be_writing-spring-boot-starter]  
[https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-developing-auto-configuration.html][https_docs.spring.io_spring-boot_docs_current_reference_html_boot-features-developing-auto-configuration.html]

[Spring Boot Starters]: https://www.nosuchfield.com/2017/10/15/Spring-Boot-Starters/
[https_github.com_Edenwds_springboot_study_tree_master_build_starter]: https://github.com/Edenwds/springboot_study/tree/master/build_starter
[https_www.cnblogs.com_yuansc_p_9088212.html]: https://www.cnblogs.com/yuansc/p/9088212.html
[https_g00glen00b.be_writing-spring-boot-starter]: https://g00glen00b.be/writing-spring-boot-starter/
[https_docs.spring.io_spring-boot_docs_current_reference_html_boot-features-developing-auto-configuration.html]: https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-developing-auto-configuration.html