Spring Boot Boot configuration principle

Configuration in Meta-inf/spring.factories

There are several main classes

Applicationcontextinitializer Creating Springaplication

Springapplicationrunlistener Start Run process

Applicationrunner

Commandlinerunner

1: Create a Springapplication object

Initialize (sources);Private voidInitialize (object[] sources) {//Saving the master configuration class    if(Sources! =NULL&& sources.length >0) {         This. Sources.addall (arrays.aslist (sources)); }    //determine whether a web app is currently     This. webenvironment =deducewebenvironment (); //Find all the Applicationcontextinitializer of the meta-inf/spring.factories configuration from the Classpath and save it.setinitializers (Collection) getspringfactoriesinstances (Applicationcontextinitializer.class)); //Find all the Applicationlistener of the eta-inf/spring.factories configuration from the ClasspathSetlisteners (Collection) getspringfactoriesinstances (Applicationlistener.class)); //Find the main configuration class with the main method from multiple configuration classes     This. Mainapplicationclass =Deducemainapplicationclass ();}

2 Running the Run method

 PublicConfigurableapplicationcontext Run (String ... args) {StopWatch StopWatch=NewStopWatch ();   Stopwatch.start (); Configurableapplicationcontext Context=NULL; Failureanalyzers Analyzers=NULL;       Configureheadlessproperty (); //get springapplicationrunlisteners; meta-inf/spring.factories from the ClasspathSpringapplicationrunlisteners listeners =getrunlisteners (args); //callback all the Get Springapplicationrunlistener.starting () methodlisteners.starting (); Try {       //encapsulating command-line argumentsApplicationarguments applicationarguments =Newdefaultapplicationarguments (args); //Prepare the EnvironmentConfigurableenvironment environment =prepareenvironment (listeners, applicationarguments); //callback Springapplicationrunlistener.environmentprepared () after the creation of the environment completes, indicating that the environment is ready to completeBanner Printedbanner=Printbanner (Environment); //create ApplicationContext; Decide whether to create an IOC or a normal IOC for the webContext =CreateApplicationContext (); Analyzers=Newfailureanalyzers (context); //Prepare the context, save the environment to the IOC, and Applyinitializers ();//applyinitializers (): Callback before saving all Applicationcontextinitializer Initialize methods//callback all the Springapplicationrunlistener of the contextprepared ();//preparecontext (context, environment, listeners, applicationarguments, Printedbanner); //Preparecontext After the completion of the operation, callback all the Springapplicationrunlistener contextloaded ();//s refreshes the container; IOC container initialization (if the web app also creates embedded tomcat); Spring Annotation edition//Scan, create, load all components in place; (Configuration classes, components, automatic configuration)Refreshcontext (context); //Retrieve all Applicationrunner and Commandlinerunner from the IOC container for callbacks//Applicationrunner First callback, Commandlinerunner callback againAfterRefresh (context, applicationarguments); //all Springapplicationrunlistener callback finished methodsListeners.finished (Context,NULL);      Stopwatch.stop (); if( This. Logstartupinfo) {         NewStartupinfologger ( This. Mainapplicationclass). logstarted (Getapplicationlog (), stopWatch); }       //the entire Springboot application launches after the completion of the launch of the IOC container;      returncontext; }   Catch(Throwable ex) {handlerunfailure (context, listeners, analyzers, ex); Throw NewIllegalStateException (ex); }}

3: Event Monitoring mechanism

Configuration in Meta-inf/spring.factories

Applicationcontextinitializer

 Public class Helloapplicationcontextinitializer Implements Applicationcontextinitializer<configurableapplicationcontext > {    @Override    publicvoid  Initialize (configurableapplicationcontext ApplicationContext) {        System. out. println ("applicationcontextinitializer...initialize ... "+ApplicationContext);}    }

Springapplicationrunlistener

 Public classHellospringapplicationrunlistener implements Springapplicationrunlistener {//Required Constructors     PublicHellospringapplicationrunlistener (springapplication application, string[] args) {} @Override Public voidstarting () {System. out. println ("springapplicationrunlistener...starting ..."); } @Override Public voidenvironmentprepared (configurableenvironment environment) {Object O= Environment.getsystemproperties ().Get("Os.name"); System. out. println ("springapplicationrunlistener...environmentprepared ."+o); } @Override Public voidcontextprepared (Configurableapplicationcontext context) {System. out. println ("springapplicationrunlistener...contextprepared ..."); } @Override Public voidcontextloaded (Configurableapplicationcontext context) {System. out. println ("springapplicationrunlistener...contextloaded ..."); } @Override Public voidfinished (configurableapplicationcontext context, Throwable exception) {System. out. println ("springapplicationrunlistener...finished ..."); }}

Configuration (meta-inf/spring.factories)

Org.springframework.context.applicationcontextinitializer=  Com.atguigu.springboot.listener.HelloApplicationContextInitializerorg.springframework.boot.SpringApplicationRunListener =Com.atguigu.springboot.listener.HelloSpringApplicationRunListener

Applicationrunner

@Component  Public class Helloapplicationrunner implements Applicationrunner {    @Override    publicvoid  Run (applicationarguments args) throws Exception {        System. out. println ("applicationrunner...run .... ") " );    }}

Commandlinerunner

@Component  Public class Hellocommandlinerunner implements Commandlinerunner {    @Override    publicvoid  Run (String ... args) throws Exception {        System. out. println ("commandlinerunner...run ... "+ arrays.aslist (args));}    }

Spring Boot Boot configuration principle