你好世界的例子(Hello World Example)

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2023-12-01

在这个例子中,我们将创建一个基于Spring Boot + MVC + Rest的Web应用程序。

第1步:创建源文件夹

E:\Test folder.创建文件夹FirstApplication E:\Test folder.

第2步:创建源文件

使用以下源代码在E:\Test folder创建FirstApplication.groovy文件 -

@RestController
class FirstApplication {
   @RequestMapping("/")
   String welcome() {
      "Welcome to xnip.cn"
   }
}

第3步:运行应用程序

输入以下命令 -

E:/Test/> spring run FirstApplication.groovy

现在,Spring Boot CLI将开始运行,下载所需的依赖项,运行嵌入式tomcat,部署应用程序并启动它。 您可以在控制台上看到以下输出 -

Resolving dependencies..........................................................
................................................................................
........................
  .   ____          _            __ _ _
 /\\/___'_ __ _ _(_)_ __  __ _\\\\
( ( )\___ | '_ | '_| | '_ \/ _> |\\\\
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, |////
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.8.RELEASE)
2017-11-07 17:36:55.703  INFO 5528 --- [       runner-0] o.s.boot.SpringApplication: 
Starting application on ...
2017-11-07 17:36:55.707  INFO 5528 --- [       runner-0] o.s.boot.SpringApplication: 
No active profile set, falling back to default profiles: default
2017-11-07 17:36:56.067  INFO 5528 --- [       runner-0] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4c108392: startup date [Tue Nov 07 17:36:
56 IST 2017]; root of context hierarchy
2017-11-07 17:36:57.327  INFO 5528 --- [       runner-0] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-11-07 17:36:57.346  INFO 5528 --- [       runner-0] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2017-11-07 17:36:57.354  INFO 5528 --- [       runner-0] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.23
2017-11-07 17:36:57.537  INFO 5528 --- [ost-startStop-1] org.apache.catalina.loader.WebappLoader  : Unknown loader org.springframework.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader@41bfad4f class org.springframew
ork.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader
2017-11-07 17:36:57.567  INFO 5528 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2017-11-07 17:36:57.567  INFO 5528 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1500 ms
2017-11-07 17:36:57.725  INFO 5528 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2017-11-07 17:36:57.730  INFO 5528 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-11-07 17:36:57.730  INFO 5528 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-11-07 17:36:57.730  INFO 5528 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-11-07 17:36:57.730  INFO 5528 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2017-11-07 17:36:58.012  INFO 5528 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4c108392: startup date [Tue Nov 07 17:36:56 IST 2017]; root of context hierarchy
2017-11-07 17:36:58.066  INFO 5528 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String FirstApplication.home()
2017-11-07 17:36:58.070  INFO 5528 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.map java.lang.object="">> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-11-07 17:36:58.071  INFO 5528 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web
.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-11-07 17:36:58.096  INFO 5528 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-07 17:36:58.096  INFO 5528 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-07 17:36:58.129  INFO 5528 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-07 17:36:58.626  INFO 5528 --- [       runner-0] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-11-07 17:36:58.696  INFO 5528 --- [       runner-0] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-11-07 17:36:58.699  INFO 5528 --- [       runner-0] o.s.boot.SpringApplication               : Started application in 3.529 seconds (JVM running for 190.196)
2017-11-07 17:37:20.217  INFO 5528 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2017-11-07 17:37:20.218  INFO 5528 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2017-11-07 17:37:20.238  INFO 5528 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 20 ms
</java.util.map>

第4步:在浏览器中浏览应用程序

我们基于弹簧的休息应用现已准备就绪。 打开网址为“ http://localhost:8080/ ”,您将看到以下输出 -

Hello World

重要的几点 (Important points)

请考虑以下几点以了解Spring CLI的工作原理.-

  • 所有依赖项JAR仅首次下载。

  • Spring CLI根据代码中使用的类和注释自动检测要下载的依赖项JAR。

  • 最后,在编译代码之后,在嵌入式tomcat上部署war文件,并在默认端口8080上启动嵌入式tomcat服务器。