图文并茂，Spring Boot Starter 万字详解！还有谁不会？

@SpringBootApplication //标注这个类是一个springboot的应用public class CommunityApplication {    public static void main(String[] args) {        //将springboot应用启动        SpringApplication.run(CommunityApplication.class, args);    }}

//表示这是一个配置类，和以前编写的配置文件一样，也可以给容器中添加组件；@Configuration

//将与配置文件绑定好的某个类注入到容器中，使其生效//进入这个HttpProperties查看，将配置文件中对应的值和HttpProperties绑定起来；//并把HttpProperties加入到ioc容器中@EnableConfigurationProperties(HttpProperties.class)

//Spring底层@Conditional注解//根据不同的条件判断，如果满足指定的条件，整个配置类里面的配置就会生效；//这里的意思就是判断当前应用是否是web应用，如果是，当前配置类生效@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)

//判断系统中有没有CharacterEncodingFilter这个类，如果有配置类才生效@ConditionalOnClass(CharacterEncodingFilter.class)

//判断配置文件中是否存在某个配置：spring.http.encoding.enabled；//matchIfMissing = true表明即使我们配置文件中不配置pring.http.encoding.enabled=true，该配置类也是默认生效的；@ConditionalOnProperty(prefix = "spring.http.encoding", value = "enabled", matchIfMissing = true)public class HttpEncodingAutoConfiguration {

  //该类已经与配置文件绑定了private final HttpProperties.Encoding properties;

  //构建该自动配置类时将与配置文件绑定的配置类作为入参传递进去public HttpEncodingAutoConfiguration(HttpProperties properties) {this.properties = properties.getEncoding();}

@Bean@ConditionalOnMissingBeanpublic CharacterEncodingFilter characterEncodingFilter() {CharacterEncodingFilter filter = new OrderedCharacterEncodingFilter();filter.setEncoding(this.properties.getCharset().name()); //注入bean时使用配置类中属性的值进行初始化，相当于将配置文件中的值映射到了组件的某些属性上filter.setForceRequestEncoding(this.properties.shouldForce(Type.REQUEST));filter.setForceResponseEncoding(this.properties.shouldForce(Type.RESPONSE));return filter; //注入配置好的bean}}

//从配置文件中获取指定的值和bean的属性进行绑定@ConfigurationProperties(prefix = "spring.http") public class HttpProperties {    // .....}

#在配置文件中开启springboot的调试类debug=true

Positive matches:-----------------

   AopAutoConfiguration matched:      - @ConditionalOnClass found required classes 'org.springframework.context.annotation.EnableAspectJAutoProxy', 'org.aspectj.lang.annotation.Aspect', 'org.aspectj.lang.reflect.Advice', 'org.aspectj.weaver.AnnotatedElement' (OnClassCondition)      - @ConditionalOnProperty (spring.aop.auto=true) matched (OnPropertyCondition)

   AopAutoConfiguration.CglibAutoProxyConfiguration matched:      - @ConditionalOnProperty (spring.aop.proxy-target-class=true) matched (OnPropertyCondition)

   AuditAutoConfiguration#auditListener matched:      - @ConditionalOnMissingBean (*: org.springframework.boot.actuate.audit.listener.AbstractAuditListener; SearchStrategy: all) did not find any beans (OnBeanCondition)

   AuditAutoConfiguration#authenticationAuditListener matched:      - @ConditionalOnClass found required class 'org.springframework.security.authentication.event.AbstractAuthenticationEvent' (OnClassCondition)      - @ConditionalOnMissingBean (*: org.springframework.boot.actuate.security.AbstractAuthenticationAuditListener; SearchStrategy: all) did not find any beans (OnBeanCondition)

Negative matches:-----------------

   ActiveMQAutoConfiguration:      Did not match:         - @ConditionalOnClass did not find required class 'javax.jms.ConnectionFactory' (OnClassCondition)

   AopAutoConfiguration.JdkDynamicAutoProxyConfiguration:      Did not match:         - @ConditionalOnProperty (spring.aop.proxy-target-class=false) did not find property 'proxy-target-class' (OnPropertyCondition)

   AppOpticsMetricsExportAutoConfiguration:      Did not match:         - @ConditionalOnClass did not find required class 'io.micrometer.appoptics.AppOpticsMeterRegistry' (OnClassCondition)

   ArtemisAutoConfiguration:      Did not match:         - @ConditionalOnClass did not find required class 'javax.jms.ConnectionFactory' (OnClassCondition)

Exclusions:-----------
    org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

Unconditional classes:----------------------
    org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration
    org.springframework.boot.actuate.autoconfigure.endpoint.jmx.JmxEndpointAutoConfiguration
    org.springframework.boot.actuate.autoconfigure.health.HealthIndicatorAutoConfiguration
    org.springframework.boot.actuate.autoconfigure.info.InfoContributorAutoConfiguration

<dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-autoconfigure</artifactId> //包含很多与自动配置相关的注解的定义，必须要引入        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-configuration-processor</artifactId> //非必须的，引入后可以在配置文件中输入我们自定义配置的时候有相应的提示，也可以通过其他.properties文件为相关类进行属性映射（SpringBoot默认使用application.yml)            <optional>true</optional>        </dependency>    <dependencies>

@Configuration @ConditionalOnxxx@ConditionalOnxxx//限定自动配置类生效的一些条件@EnableConfigurationProperties(xxxProperties.class)public class xxxAutoConfiguration {@Autowiredprivate xxxProperties properties;    @Bean    public static BeanYouNeed beanYouNeed() {    BeanYouNeed bean = new BeanYouNeed()    bean.setField(properties.get(field));    bean.setField(properties.get(field));    bean.setField(properties.get(field));        ......    }}

@ConfigurationProperties(prefix = "your properties") //使用@ConfigurationProperties注解绑定配置文件public class xxxProperties {
    private boolean enabled = true;
    private String clientId;
    private String beanName;
    private String scanBasePackage;
    private String path;
    private String token;}

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\com.meituan.xframe.boot.mcc.autoconfigure.xxxAutoConfiguration

<dependencies>    ================================================================    添加了对autoconfigure模块的引用        <dependency>            <groupId>com.test.starter</groupId>            <artifactId>xxx-spring-boot-autoconfigure</artifactId>        </dependency>    ===============================================================    其他的一些必要依赖项        <dependency>            <groupId>commons-collections</groupId>            <artifactId>commons-collections</artifactId>        </dependency>    </dependencies>