Spring Boot的自动配置的原理
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
