Spring Boot在进行SpringApplication对象实例化时会加载META-INF/spring.factories文件，将该配置文件中的配置载入到Spring容器。
1.1.1. Maven下载源码
通过 dependency:sources 该命令可以下载该项目中所有的依赖的包的源码。
1.1.2. 源码分析
org.springframework.boot.SpringApplication：
org.springframework.core.io.support.SpringFactoriesLoader:
由此可见，读取该配置文件来加载内容。
1.1.3. Spring.factories文件
1 # Initializers 2 3 org.springframework.context.ApplicationContextInitializer= 4 5 org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer, 6 7 org.springframework.boot.autoconfigure.logging.AutoConfigurationReportLoggingInitializer 8 9 10 11 # Application Listeners 12 13 org.springframework.context.ApplicationListener= 14 15 org.springframework.boot.autoconfigure.BackgroundPreinitializer 16 17 18 19 # Auto Configuration Import Listeners 20 21 org.springframework.boot.autoconfigure.AutoConfigurationImportListener= 22 23 org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener 24 25 26 27 # Auto Configuration Import Filters 28 29 org.springframework.boot.autoconfigure.AutoConfigurationImportFilter= 30 31 org.springframework.boot.autoconfigure.condition.OnClassCondition 32 33 34 35 # Auto Configure 36 37 org.springframework.boot.autoconfigure.EnableAutoConfiguration= 38 39 org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration, 40 41 org.springframework.boot.autoconfigure.aop.AopAutoConfiguration, 42 43 org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration, 44 45 org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration, 46 47 org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration, 48 49 org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration, 50 51 org.springframework.boot.autoconfigure.cloud.CloudAutoConfiguration, 52 53 org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration, 54 55 org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration, 56 57 org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration, 58 59 org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration, 60 61 org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration, 62 63 org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration, 64 65 org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration, 66 67 org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration, 68 69 org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration, 70 71 org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration, 72 73 org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration, 74 75 org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration, 76 77 org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration, 78 79 org.springframework.boot.autoconfigure.data.ldap.LdapDataAutoConfiguration, 80 81 org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration, 82 83 org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration, 84 85 org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration, 86 87 org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration, 88 89 org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration, 90 91 org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration, 92 93 org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration, 94 95 org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration, 96 97 org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration, 98 99 org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration, 100 101 org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration, 102 103 org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration, 104 105 org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration, 106 107 org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration, 108 109 org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration, 110 111 org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration, 112 113 org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration, 114 115 org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration, 116 117 org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration, 118 119 org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration, 120 121 org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration, 122 123 org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration, 124 125 org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration, 126 127 org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration, 128 129 org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration, 130 131 org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration, 132 133 org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration, 134 135 org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration, 136 137 org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration, 138 139 org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration, 140 141 org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration, 142 143 org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration, 144 145 org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration, 146 147 org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration, 148 149 org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration, 150 151 org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration, 152 153 org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration, 154 155 org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration, 156 157 org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration, 158 159 org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration, 160 161 org.springframework.boot.autoconfigure.mobile.DeviceResolverAutoConfiguration, 162 163 org.springframework.boot.autoconfigure.mobile.DeviceDelegatingViewResolverAutoConfiguration, 164 165 org.springframework.boot.autoconfigure.mobile.SitePreferenceAutoConfiguration, 166 167 org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration, 168 169 org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration, 170 171 org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration, 172 173 org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration, 174 175 org.springframework.boot.autoconfigure.reactor.ReactorAutoConfiguration, 176 177 org.springframework.boot.autoconfigure.security.SecurityAutoConfiguration, 178 179 org.springframework.boot.autoconfigure.security.SecurityFilterAutoConfiguration, 180 181 org.springframework.boot.autoconfigure.security.FallbackWebSecurityAutoConfiguration, 182 183 org.springframework.boot.autoconfigure.security.oauth2.OAuth2AutoConfiguration, 184 185 org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration, 186 187 org.springframework.boot.autoconfigure.session.SessionAutoConfiguration, 188 189 org.springframework.boot.autoconfigure.social.SocialWebAutoConfiguration, 190 191 org.springframework.boot.autoconfigure.social.FacebookAutoConfiguration, 192 193 org.springframework.boot.autoconfigure.social.LinkedInAutoConfiguration, 194 195 org.springframework.boot.autoconfigure.social.TwitterAutoConfiguration, 196 197 org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration, 198 199 org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration, 200 201 org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration, 202 203 org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration, 204 205 org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration, 206 207 org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration, 208 209 org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration, 210 211 org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration, 212 213 org.springframework.boot.autoconfigure.web.HttpEncodingAutoConfiguration, 214 215 org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration, 216 217 org.springframework.boot.autoconfigure.web.MultipartAutoConfiguration, 218 219 org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration, 220 221 org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration, 222 223 org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration, 224 225 org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration, 226 227 org.springframework.boot.autoconfigure.websocket.WebSocketMessagingAutoConfiguration, 228 229 org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration 230 231 232 233 # Failure analyzers 234 235 org.springframework.boot.diagnostics.FailureAnalyzer= 236 237 org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer, 238 239 org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer, 240 241 org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer 242 243 244 245 # Template availability providers 246 247 org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider= 248 249 org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider, 250 251 org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider, 252 253 org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider, 254 255 org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider, 256 257 org.springframework.boot.autoconfigure.web.JspTemplateAvailabilityProvider
1.1.4. 举例：Redis的自动配置
从上述的配置中可以看出，org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration是Redis的自动配置。
内容：
1.1.5. 条件注解
