SpringBoot 2.0 系列002 --运行流程分析


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SpringBoot 2.0 系列002 --运行流程分析

SpringBoot 2.0 系列001 -- 入门介绍以及相关概念

1. SpringBoot运行的几种方式

1.1 开发环境,右键配置类main方法运行

配置如下,引入相关pom依赖,运行main方法即可启动简单的SpringBoot web应用。

//开启SpringBoot自动注入配置  等价于原来的SpringBootApplication @EnableAutoConfiguration //开启RestController注解  含有ResponseBody 即非页面形式 @RestController public class SpringBootApplication {      @GetMapping("/")     public String home() {         return "Hello World!";     }      /**      * 开启SpringBoot服务      * @param args      */     public static void main(String[] args) {         //等价于 new SpringApplication(SpringBootApplication.class).run(args);         SpringApplication.run(SpringBootApplication.class,args);     } }

1.2 jar文件运行

其他部分与上述相同,需要注意的是pom文件需要加入

<plugins>             <plugin>                 <groupId>org.springframework.boot</groupId>                 <artifactId>spring-boot-maven-plugin</artifactId>             </plugin>         </plugins>

打包方式选择为jar

<packaging>jar</packaging>

最后mvn package打包 ,idea里面如下

运行方式1,如下

运行方式2,如下

D:\work\ideawork\SpringBootLearn\chapter02\target>java -jar chapter02-2.0.1.RELEASE.jar    .   ____          _            __ _ _  /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \  \\/  ___)| |_)| | | | | || (_| |  ) ) ) )   '  |____| .__|_| |_|_| |_\__, | / / / /  =========|_|==============|___/=/_/_/_/  :: Spring Boot ::        (v2.0.1.RELEASE)  2018-05-11 09:42:52.870  INFO 9720 --- [           main] com.ricky.SpringBootApplication          : Starting SpringBootApplication v2.0.1.RELEASE on jsb-bgt with PID 9720 (D:\work\ideawork\SpringBootLearn\chapter02\target\chapter02-2.0.1.RELEASE.jar started by zdwljs in D:\work\ideawork\SpringBootLearn\chapter02\target) 2018-05-11 09:42:52.877  INFO 9720 --- [           main] com.ricky.SpringBootApplication          : No active profile set, falling back to default profiles: default 2018-05-11 09:42:52.979  INFO 9720 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5f8ed237: startup date [Fri May 11 09:42:52 CST 2018]; root of context hierarchy 2018-05-11 09:42:55.596  INFO 9720 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http) 2018-05-11 09:43:01.810  INFO 9720 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat] 2018-05-11 09:43:01.811  INFO 9720 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.29 2018-05-11 09:43:01.827  INFO 9720 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [D:\Program Files\Java\jdk1.8.0_161\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;d:\work\Git\cmd;C:\Program Files (x86)\MySQL\MySQL Server 5.5\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Users\zdwljs\AppData\Local\Microsoft\WindowsApps;D:\Program Files\Java\jdk1.8.0_161\bin;;.] 2018-05-11 09:43:01.988  INFO 9720 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext 2018-05-11 09:43:01.991  INFO 9720 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 9018 ms 2018-05-11 09:43:02.238  INFO 9720 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/] 2018-05-11 09:43:02.263  INFO 9720 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*] 2018-05-11 09:43:02.264  INFO 9720 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] 2018-05-11 09:43:02.267  INFO 9720 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*] 2018-05-11 09:43:02.271  INFO 9720 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*] 2018-05-11 09:43:02.437  INFO 9720 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-05-11 09:43:02.877  INFO 9720 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5f8ed237: startup date [Fri May 11 09:42:52 CST 2018]; root of context hierarchy 2018-05-11 09:43:03.069  INFO 9720 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public java.lang.String com.ricky.SpringBootApplication.home() 2018-05-11 09:43:03.079  INFO 9720 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest) 2018-05-11 09:43:03.083  INFO 9720 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) 2018-05-11 09:43:03.139  INFO 9720 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-05-11 09:43:03.140  INFO 9720 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-05-11 09:43:03.386  INFO 9720 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup 2018-05-11 09:43:03.457  INFO 9720 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path '' 2018-05-11 09:43:03.466  INFO 9720 --- [           main] com.ricky.SpringBootApplication          : Started SpringBootApplication in 11.232 seconds (JVM running for 11.882)

通过ctrl-c可以退出

1.3 war包方式

1.3.1 war形式基本是使用外部tomcat,则需要将内置tomcat依赖过滤掉,且需要添加开发servlet依赖。

<dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-web</artifactId>             <exclusions>                 <!--排除tomcat依赖-->                 <exclusion>                     <groupId>org.springframework.boot</groupId>                     <artifactId>spring-boot-starter-tomcat</artifactId>                 </exclusion>             </exclusions>         </dependency>         <!--引入servlet支持-->         <!--servlet依赖-->         <!--httpServletRequest等相关文件-->         <dependency>             <groupId>javax.servlet</groupId>             <artifactId>javax.servlet-api</artifactId>             <version>3.1.0</version>             <scope>provided</scope>         </dependency>         <!--引入servlet支持结束-->

1.3.2 注意将打包方式改为war形式

<packaging>war</packaging>

1.3.3 两种加载方式

  • 需要配置启动类 ,如下

继承SpringBootServletInitializer,重写configure方法。

//开启SpringBoot自动注入配置  等价于原来的SpringBootApplication @EnableAutoConfiguration //开启RestController注解  含有ResponseBody 即非页面形式 @RestController public class SpringBootApplicationServletInitializer extends SpringBootServletInitializer{      @GetMapping("/")     public String home(HttpServletRequest request) {         return "Hello World!";     }      @Override     protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {         return builder.sources(SpringBootApplicationServletInitializer.class);     }      }
  • 另一种则是不需要继承SpringBootServletInitializer。保持与jar文件方式一致即可。 虽然也可以正常访问。但是application.yml中的配置不生效。需要通过其他方式进行参数配置。

1.3.3 打包运行

  • 1、 mvn package打包,生成chapter02-2.0.1.RELEASE.war 文件。

  • 2、将war文件放到webapp目录下 

  • 3、启动tomcat。(注意:测试发现是没有spring的日志,但是访问正常)

11-May-2018 11:53:34.687 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server version:        Apache Tomcat/8.5.29 11-May-2018 11:53:34.694 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server built:          Mar 5 2018 13:11:12 UTC 11-May-2018 11:53:34.697 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server number:         8.5.29.0 11-May-2018 11:53:34.698 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name:               Windows 10 11-May-2018 11:53:34.698 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Version:            10.0 11-May-2018 11:53:34.698 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Architecture:          amd64 11-May-2018 11:53:34.699 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java Home:             D:\Program Files\Java\jdk1.8.0_161\jre 11-May-2018 11:53:34.703 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Version:           1.8.0_161-b12 11-May-2018 11:53:34.704 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Vendor:            Oracle Corporation 11-May-2018 11:53:34.706 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:         D:\work\apache-tomcat-8.5.29 11-May-2018 11:53:34.708 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:         D:\work\apache-tomcat-8.5.29 11-May-2018 11:53:34.708 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.config.file=D:\work\apache-tomcat-8.5.29\conf\logging.properties 11-May-2018 11:53:34.709 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager 11-May-2018 11:53:34.710 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djdk.tls.ephemeralDHKeySize=2048 11-May-2018 11:53:34.714 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.webresources 11-May-2018 11:53:34.718 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dignore.endorsed.dirs= 11-May-2018 11:53:34.723 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.base=D:\work\apache-tomcat-8.5.29 11-May-2018 11:53:34.725 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.home=D:\work\apache-tomcat-8.5.29 11-May-2018 11:53:34.731 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.io.tmpdir=D:\work\apache-tomcat-8.5.29\temp 11-May-2018 11:53:34.739 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent Loaded APR based Apache Tomcat Native library [1.2.16] using APR version [1.6.3]. 11-May-2018 11:53:34.740 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true]. 11-May-2018 11:53:34.741 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR/OpenSSL configuration: useAprConnector [false], useOpenSSL [true] 11-May-2018 11:53:35.865 信息 [main] org.apache.catalina.core.AprLifecycleListener.initializeSSL OpenSSL successfully initialized [OpenSSL 1.0.2m  2 Nov 2017] 11-May-2018 11:53:36.129 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["http-nio-8080"] 11-May-2018 11:53:36.509 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read 11-May-2018 11:53:36.519 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["ajp-nio-8009"] 11-May-2018 11:53:36.532 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read 11-May-2018 11:53:36.533 信息 [main] org.apache.catalina.startup.Catalina.load Initialization processed in 2548 ms 11-May-2018 11:53:36.584 信息 [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina] 11-May-2018 11:53:36.584 信息 [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.29 11-May-2018 11:53:36.629 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployWAR Deploying web application archive [D:\work\apache-tomcat-8.5.29\webapps\chapter02-2.0.1.RELEASE.war] 11-May-2018 11:53:40.555 信息 [localhost-startStop-1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. 11-May-2018 11:53:41.025 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployWAR Deployment of web application archive [D:\work\apache-tomcat-8.5.29\webapps\chapter02-2.0.1.RELEASE.war] has finished in [4,393] ms 11-May-2018 11:53:41.148 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\work\apache-tomcat-8.5.29\webapps\docs] 11-May-2018 11:53:41.258 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\work\apache-tomcat-8.5.29\webapps\docs] has finished in [119] ms 11-May-2018 11:53:41.266 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\work\apache-tomcat-8.5.29\webapps\examples] 11-May-2018 11:53:41.987 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\work\apache-tomcat-8.5.29\webapps\examples] has finished in [721] ms 11-May-2018 11:53:42.048 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\work\apache-tomcat-8.5.29\webapps\host-manager] 11-May-2018 11:53:42.114 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\work\apache-tomcat-8.5.29\webapps\host-manager] has finished in [66] ms 11-May-2018 11:53:42.116 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\work\apache-tomcat-8.5.29\webapps\manager] 11-May-2018 11:53:42.175 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\work\apache-tomcat-8.5.29\webapps\manager] has finished in [59] ms 11-May-2018 11:53:42.176 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\work\apache-tomcat-8.5.29\webapps\ROOT] 11-May-2018 11:53:42.240 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\work\apache-tomcat-8.5.29\webapps\ROOT] has finished in [64] ms 11-May-2018 11:53:42.254 信息 [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"] 11-May-2018 11:53:42.274 信息 [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"] 11-May-2018 11:53:42.284 信息 [main] org.apache.catalina.startup.Catalina.start Server startup in 5749 ms

查看tomcat的App服务 http://localhost:8080/manager/html

  • 4、点击chapter02-2.0.1.RELEASE访问 我们部署的项目。

2. SpringBoot是怎么运行起来的?

我们以jar文件方式为例进行讲解。

2.1 jar文件目录结构

  • 切入jar文件所在目录,执行命令:
D:\work\xxxxx\SpringBootLearn\chapter02\target>jar tf chapter02-2.0.1.RELEASE.jar META-INF/ META-INF/MANIFEST.MF org/ org/springframework/ org/springframework/boot/ org/springframework/boot/loader/ org/springframework/boot/loader/util/ org/springframework/boot/loader/util/SystemPropertyUtils.class org/springframework/boot/loader/PropertiesLauncher$1.class org/springframework/boot/loader/PropertiesLauncher$PrefixMatchingArchiveFilter.class org/springframework/boot/loader/Launcher.class org/springframework/boot/loader/PropertiesLauncher$ArchiveEntryFilter.class org/springframework/boot/loader/PropertiesLauncher.class org/springframework/boot/loader/jar/ org/springframework/boot/loader/jar/JarURLConnection.class org/springframework/boot/loader/jar/JarURLConnection$1.class org/springframework/boot/loader/jar/Bytes.class org/springframework/boot/loader/jar/JarURLConnection$JarEntryName.class org/springframework/boot/loader/jar/JarFileEntries$1.class org/springframework/boot/loader/jar/JarEntry.class org/springframework/boot/loader/jar/JarFileEntries.class org/springframework/boot/loader/jar/JarEntryFilter.class org/springframework/boot/loader/jar/ZipInflaterInputStream.class org/springframework/boot/loader/jar/StringSequence.class org/springframework/boot/loader/jar/JarFile$1.class org/springframework/boot/loader/ExecutableArchiveLauncher.class org/springframework/boot/loader/archive/ org/springframework/boot/loader/archive/JarFileArchive$JarFileEntry.class org/springframework/boot/loader/archive/ExplodedArchive$FileEntryIterator.class org/springframework/boot/loader/archive/ExplodedArchive$FileEntry.class org/springframework/boot/loader/archive/ExplodedArchive.class org/springframework/boot/loader/archive/ExplodedArchive$1.class org/springframework/boot/loader/archive/JarFileArchive$EntryIterator.class org/springframework/boot/loader/archive/Archive$Entry.class org/springframework/boot/loader/archive/Archive.class org/springframework/boot/loader/archive/Archive$EntryFilter.class org/springframework/boot/loader/archive/ExplodedArchive$FileEntryIterator$EntryComparator.class org/springframework/boot/loader/archive/JarFileArchive.class org/springframework/boot/loader/data/ org/springframework/boot/loader/data/RandomAccessDataFile$FileAccess.class org/springframework/boot/loader/data/RandomAccessDataFile$DataInputStream.class org/springframework/boot/loader/JarLauncher.class org/springframework/boot/loader/jar/JarFile.class org/springframework/boot/loader/jar/CentralDirectoryParser.class org/springframework/boot/loader/jar/AsciiBytes.class org/springframework/boot/loader/jar/FileHeader.class org/springframework/boot/loader/jar/JarFile$JarFileType.class org/springframework/boot/loader/jar/Handler.class org/springframework/boot/loader/jar/JarFileEntries$EntryIterator.class org/springframework/boot/loader/jar/CentralDirectoryVisitor.class org/springframework/boot/loader/jar/CentralDirectoryEndRecord.class org/springframework/boot/loader/jar/CentralDirectoryFileHeader.class org/springframework/boot/loader/jar/JarFile$2.class org/springframework/boot/loader/LaunchedURLClassLoader.class org/springframework/boot/loader/MainMethodRunner.class org/springframework/boot/loader/data/RandomAccessDataFile.class org/springframework/boot/loader/WarLauncher.class org/springframework/boot/loader/data/RandomAccessDataFile$1.class org/springframework/boot/loader/data/RandomAccessData.class org/springframework/boot/loader/LaunchedURLClassLoader$UseFastConnectionExceptionsEnumeration.class BOOT-INF/ BOOT-INF/classes/ BOOT-INF/classes/com/ BOOT-INF/classes/com/ricky/ META-INF/maven/ META-INF/maven/chapter02/ META-INF/maven/chapter02/chapter02/ BOOT-INF/classes/com/ricky/SpringBootApplication.class META-INF/maven/chapter02/chapter02/pom.properties META-INF/maven/chapter02/chapter02/pom.xml BOOT-INF/lib/ BOOT-INF/lib/spring-boot-starter-web-2.0.1.RELEASE.jar BOOT-INF/lib/spring-boot-starter-2.0.1.RELEASE.jar BOOT-INF/lib/spring-boot-2.0.1.RELEASE.jar BOOT-INF/lib/spring-boot-autoconfigure-2.0.1.RELEASE.jar BOOT-INF/lib/spring-boot-starter-logging-2.0.1.RELEASE.jar BOOT-INF/lib/logback-classic-1.2.3.jar BOOT-INF/lib/logback-core-1.2.3.jar BOOT-INF/lib/slf4j-api-1.7.25.jar BOOT-INF/lib/log4j-to-slf4j-2.10.0.jar BOOT-INF/lib/log4j-api-2.10.0.jar BOOT-INF/lib/jul-to-slf4j-1.7.25.jar BOOT-INF/lib/javax.annotation-api-1.3.2.jar BOOT-INF/lib/spring-core-5.0.5.RELEASE.jar BOOT-INF/lib/spring-jcl-5.0.5.RELEASE.jar BOOT-INF/lib/snakeyaml-1.19.jar BOOT-INF/lib/spring-boot-starter-json-2.0.1.RELEASE.jar BOOT-INF/lib/jackson-databind-2.9.5.jar BOOT-INF/lib/jackson-annotations-2.9.0.jar BOOT-INF/lib/jackson-core-2.9.5.jar BOOT-INF/lib/jackson-datatype-jdk8-2.9.5.jar BOOT-INF/lib/jackson-datatype-jsr310-2.9.5.jar BOOT-INF/lib/jackson-module-parameter-names-2.9.5.jar BOOT-INF/lib/spring-boot-starter-tomcat-2.0.1.RELEASE.jar BOOT-INF/lib/tomcat-embed-core-8.5.29.jar BOOT-INF/lib/tomcat-embed-el-8.5.29.jar BOOT-INF/lib/tomcat-embed-websocket-8.5.29.jar BOOT-INF/lib/hibernate-validator-6.0.9.Final.jar BOOT-INF/lib/validation-api-2.0.1.Final.jar BOOT-INF/lib/jboss-logging-3.3.2.Final.jar BOOT-INF/lib/classmate-1.3.4.jar BOOT-INF/lib/spring-web-5.0.5.RELEASE.jar BOOT-INF/lib/spring-beans-5.0.5.RELEASE.jar BOOT-INF/lib/spring-webmvc-5.0.5.RELEASE.jar BOOT-INF/lib/spring-aop-5.0.5.RELEASE.jar BOOT-INF/lib/spring-context-5.0.5.RELEASE.jar BOOT-INF/lib/spring-expression-5.0.5.RELEASE.jar
  • 打开MANIFEST.MF文件
Manifest-Version: 1.0 Implementation-Title: chapter01 Maven Webapp Implementation-Version: 2.0.1.RELEASE Built-By: zdwljs Implementation-Vendor-Id: chapter02 Spring-Boot-Version: 2.0.1.RELEASE Main-Class: org.springframework.boot.loader.JarLauncher Start-Class: com.ricky.SpringBootApplication Spring-Boot-Classes: BOOT-INF/classes/ Spring-Boot-Lib: BOOT-INF/lib/ Created-By: Apache Maven 3.3.9 Build-Jdk: 1.8.0_161 Implementation-URL: http://www.example.com

Start-class是我们的SpringBootApplication类,即jar文件方式启动 跟开发环境右键main方法运行方式一致

Main-Class则是JarLauncher。如果打包方式是war的话则是WarLauncher。此类工作内容是讲字节码文件加载到jvm中。

2.2 SpringBoot执行

由上述分析可知,com.ricky.SpringBootApplication是我们加载SB的入口。

  • 入口

SpringApplication 的静态run方法。也可以手动new SpringApplication

SpringApplication.run(SpringBootApplication.class,args);
    • 入口调用链1
    /**     * 调用run方法  返回ConfigurableApplicationContext对象 此对象用法在03章节做讲解     */  	public static ConfigurableApplicationContext run(Class<?> primarySource,  			String... args) {  		return run(new Class<?>[] { primarySource }, args);  	}
    • 入口调用链1
    /**         *  此处有两步处理         *   1. 创建SpringApplication 对象         *   2. 执行该对象的run方法         */  		public static ConfigurableApplicationContext run(Class<?>[] primarySources,     			String[] args) {     		return new SpringApplication(primarySources).run(args);     	}
  • 创建SpringApplication 对象的过程

    • 第一步 调用构造方法

      //调用构造方法 	public SpringApplication(Class<?>... primarySources) { 		this(null, primarySources); 	}
    • 第2步 调用构造方法

      //调用构造方法 	public SpringApplication(Class<?>... primarySources) { 		this(null, primarySources); 	}
    • 第3步 具体构造方法解析

      //调用构造方法 	public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) { 	        //默认resourceLoader 为null     		this.resourceLoader = resourceLoader; 	        //校验primarySources不为空     		Assert.notNull(primarySources, "PrimarySources must not be null"); 	        //赋值primarySources集合对象  说明此处是可以传递多个.class对象 当我们的启动类不在同一级包中            // com.ricky/ricky02  我们的启动类在ricky中,默认是只扫描ricky包中的类,如果想扫描ricky02中 可以将需要扫描的类放到此处。     		this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));     		//加载webApplicationType 对象 推断是web环境 还是非web环境 	        this.webApplicationType = deduceWebApplicationType();            //设置实例为ApplicationContextInitializer的Spring工厂实例            //可以通过spring.factories文件注入 继承自ApplicationContextInitializer的类            //也可以调用addInitializer方法手动注入     		setInitializers((Collection) getSpringFactoriesInstances(     				ApplicationContextInitializer.class)); 	        //注入ApplicationListener实例的监听  实现方式类似上边  通过文件或者add方法都可以     		setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class)); 	        // 通过堆栈里获取的方式,判断main函数,找到原始启动的main函数     		this.mainApplicationClass = deduceMainApplicationClass();     	}
    • 第4步 run方法说明

      //执行run方法 返回ConfigurableApplicationContext 对象 public ConfigurableApplicationContext run(String... args) {           //开启执行时间记录器 		StopWatch stopWatch = new StopWatch(); 		stopWatch.start();           //定义context 		ConfigurableApplicationContext context = null;           //定义exceptionReporters 		Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();           //设置java.awt.headless模式 主要是在缺少显示设备和键盘鼠标等下的支持  设置系统变量为true 		configureHeadlessProperty();           //根据传递的参数 加载spirng.factories中的SpringApplicationRunListener实例监听对象 		SpringApplicationRunListeners listeners = getRunListeners(args);           //启动监听 		listeners.starting(); 		try {               // 将传入的参数转换为ApplicationArguments格式 			ApplicationArguments applicationArguments = new DefaultApplicationArguments( 					args);               // 根据applicationArguments准备基础环境变量 监听listeners变量 绑定到Spring中               //如果webApplicationType是0则做下转换处理  最后 attach做些检查判断处理 			ConfigurableEnvironment environment = prepareEnvironment(listeners, 					applicationArguments); 	         // 从环境变量中检查和设置spring.beaninfo.ignore的状态 true或false 			configureIgnoreBeanInfo(environment); 	         // 从环境变量中检查和设置banner.mode的模式  OFF时不打印               // 这部分是sb项目启动时显示几行springboot字符串头像               //自定义配置可参阅 SpringApplicationBannerPrinter 			Banner printedBanner = printBanner(environment); 	         //创建应用上下文环境 检查是web环境还是默认环境等生成相对应环境 			context = createApplicationContext(); 	         // 从spring.factories中获取SpringBootExceptionReporter类型的实例  			exceptionReporters = getSpringFactoriesInstances( 					SpringBootExceptionReporter.class, 					new Class[] { ConfigurableApplicationContext.class }, context); 	         //准备context                // 参阅第五步 			prepareContext(context, environment, listeners, applicationArguments, 					printedBanner); 	         //刷新上下文context  注意根据ServletWeb和ReactiveWeb以及默认的applicationContext的不同来进行具体刷新 			refreshContext(context); 	         // 刷新后的操作  现在是保留方法 			afterRefresh(context, applicationArguments); 	          //结束执行时间记录器 			stopWatch.stop(); 	         // 是否开启启动日志 			if (this.logStartupInfo) { 				new StartupInfoLogger(this.mainApplicationClass) 						.logStarted(getApplicationLog(), stopWatch); 			} 	         // 发布事件  context.publishEvent(ApplicationStartedEvent) 			listeners.started(context); 	         // 将ApplicationRunner和CommandLineRunner类型的回调处理 			callRunners(context, applicationArguments); 		} 		catch (Throwable ex) { 			handleRunFailure(context, ex, exceptionReporters, listeners); 			throw new IllegalStateException(ex); 		}  		try { 	         // context.publishEvent(ApplicationReadyEvent) 发布监听 			listeners.running(context); 		} 		catch (Throwable ex) { 			handleRunFailure(context, ex, exceptionReporters, null); 			throw new IllegalStateException(ex); 		} 		return context; 	}
    • 第5步 准备context

      private void prepareContext(ConfigurableApplicationContext context, 			ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, 			ApplicationArguments applicationArguments, Banner printedBanner) {        // 设置context环境变量 		context.setEnvironment(environment);        // 注册internalConfigurationBeanNameGenerator实例  setResourceLoader 或者setClassLoader 		postProcessApplicationContext(context);         // 执行ApplicationContextInitializer.initialize方法 		applyInitializers(context);         // 设置监听上下文 		listeners.contextPrepared(context);         // 如果启动日志开的话 则启动日志实例 		if (this.logStartupInfo) { 			logStartupInfo(context.getParent() == null); 			logStartupProfileInfo(context); 		} 		// Add boot specific singleton beans         // 通过bean工厂注册springApplicationArguments的单例对象 		context.getBeanFactory().registerSingleton("springApplicationArguments", 				applicationArguments);         // 如果 printedBanner 不为空则通过bean工厂注册springBootBanner的单例对象 		if (printedBanner != null) { 			context.getBeanFactory().registerSingleton("springBootBanner", printedBanner); 		}  		// Load the sources  加载sources 		Set<Object> sources = getAllSources(); 		Assert.notEmpty(sources, "Sources must not be empty"); 		             //通过 createBeanDefinitionLoader方法  获取lBeanDefinitionLoader 并设置beanNameGenerator、environment、resourceLoader        // 最后根据类型进行装载registerbean 常见的类型有xml ,annotation,package,resouces等等 最后返回bean数量 		load(context, sources.toArray(new Object[0])); 		             // 通过SimpleApplicationEventMulticaster的Executor 去invoke是ApplicationListener类型的listener           // 循环执行listener.onApplicationEvent(event); 		listeners.contextLoaded(context); 	}

2.3 总结

通过分析,我们发现sb在启动的时候会校验执行环境(web或者其他),根据args传入参数的不同执行不同逻辑,同时扫描的方式有包类型、resource、注解、xml等(load方法装载bean实例)。 还可以根据spring.factories注入listener 、Initializers、event等等对象。

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  • 作者ricky
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本文发表于2018年05月14日 23:23
(c)注:本文转载自https://my.oschina.net/lt0314/blog/1812299,转载目的在于传递更多信息,并不代表本网赞同其观点和对其真实性负责。如有侵权行为,请联系我们,我们会及时删除.

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