SpringBoot自动配置的实现原理

@target ({elementtype.type})

@retention (retentionpolicy.runtime)

@documented

@inherited

@autoconfigurationpackage

@import ({enableautoconfigurationimportselector. class })

public @interface enableautoconfiguration {

   string enabled_override_property = "spring.boot.enableautoconfiguration" ;

   class <?>[] exclude() default {};

   string[] excludename() default {};

}

# initializers

org.springframework.context.applicationcontextinitializer=\

org.springframework.boot.autoconfigure.sharedmetadatareaderfactorycontextinitializer,\

org.springframework.boot.autoconfigure.logging.autoconfigurationreportlogginginitializer

# application listeners

org.springframework.context.applicationlistener=\

org.springframework.boot.autoconfigure.backgroundpreinitializer

# auto configuration import listeners

org.springframework.boot.autoconfigure.autoconfigurationimportlistener=\

org.springframework.boot.autoconfigure.condition.conditionevaluationreportautoconfigurationimportlistener

# auto configuration import filters

org.springframework.boot.autoconfigure.autoconfigurationimportfilter=\

org.springframework.boot.autoconfigure.condition.onclasscondition

# auto configure

org.springframework.boot.autoconfigure.enableautoconfiguration=\

org.springframework.boot.autoconfigure.admin.springapplicationadminjmxautoconfiguration,\

org.springframework.boot.autoconfigure.aop.aopautoconfiguration,\

org.springframework.boot.autoconfigure.amqp.rabbitautoconfiguration,\

org.springframework.boot.autoconfigure.batch.batchautoconfiguration,\

org.springframework.boot.autoconfigure.cache.cacheautoconfiguration,\

org.springframework.boot.autoconfigure.cassandra.cassandraautoconfiguration,\

org.springframework.boot.autoconfigure.cloud.cloudautoconfiguration,\

org.springframework.boot.autoconfigure.context.configurationpropertiesautoconfiguration,\

<?xml version= "1.0" encoding= "utf-8" ?>

<project xmlns= "http://maven.apache.org/pom/4.0.0" xmlns:xsi= "http://www.w3.org/2001/xmlschema-instance"

   xsi:schemalocation= "http://maven.apache.org/pom/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

   <modelversion> 4.0 . 0 </modelversion>

   <groupid>cn.miaolovezhen</groupid>

   <artifactid>spring-boot-starter-test</artifactid>

   <version> 0.0 . 1 -snapshot</version>

   <packaging>jar</packaging>

   <name>spring-boot-starter-test</name>

   <description>demo project for spring boot</description>

   <parent>

    <groupid>org.springframework.boot</groupid>

    <artifactid>spring-boot-starter-parent</artifactid>

    <version> 1.5 . 6 .release</version>

    <relativepath/> <!-- lookup parent from repository -->

   </parent>

   <properties>

    <project.build.sourceencoding>utf- 8 </project.build.sourceencoding>

    <project.reporting.outputencoding>utf- 8 </project.reporting.outputencoding>

    <java.version> 1.8 </java.version>

   </properties>

   <dependencies>

    <dependency>

      <groupid>org.springframework.boot</groupid>

      <artifactid>spring-boot-autoconfigure</artifactid>

      <version> 1.5 . 4 .release</version>

    </dependency>

   </dependencies>

</project>

@configurationproperties (prefix = "test" )

public class testproperties {

   private static final string msg = "springboot" ;

   private string msg = msg;

   public string getmsg() {

     return msg;

   }

   public void setmsg(string msg) {

     this .msg = msg;

   }

}

public class testservice {

   private string msg;

   public string sayhello(){

     return "hello " + msg;

   }

   public string getmsg() {

     return msg;

   }

   public void setmsg(string msg) {

     this .msg = msg;

   }

}

@configuration

@enableconfigurationproperties (testproperties. class )

@conditionalonclass (testservice. class )

@conditionalonproperty (prefix = "test" , value = "enabled" , matchifmissing = true )

public class testserviceautoconfiguration {

   @autowired

   testproperties testproperties;

   @bean

   @conditionalonmissingbean (testservice. class )

   public testservice testservice(){

     testservice testservice = new testservice();

     testservice.setmsg(testproperties.getmsg());

     return testservice;

   }

}

org.springframework.boot.autoconfigure.enableautoconfiguration=\

cn.miaolovezhen.testserviceautoconfiguration