Spring Boot快速入门

本章将演示如何使用Maven和Gradle创建Spring Boot应用程序。

前提条件

系统需要具有以下创建Spring Boot应用程序的最低要求 -

• Java 7
• Maven 3.2
• Gradle 2.5

Spring Boot CLI

Spring Boot CLI是一个命令行工具，它用于运行Groovy脚本。它是使用Spring Boot命令行界面创建Spring Boot应用程序的最简单方法。可以在命令提示符下创建，运行和测试应用程序。

本节介绍手动安装Spring Boot CLI所涉及的步骤。 如需进一步的帮助，可以使用以下链接:

• https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#getting-started-installing-spring-boot

还可以从Spring Software存储库下载Spring CLI发行版:

• https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#getting-started-manual-cli-installation

对于手动安装，需要使用以下两个文件夹 -

• spring-boot-cli-2.0.0.BUILD-SNAPSHOT-bin.zip
• spring-boot-cli-2.0.0.BUILD-SNAPSHOT-bin.tar.gz

下载后，解压缩归档文件并按照install.txt文件中给出的步骤进行操作。 并不是说它不需要任何环境设置。
在Windows中，转到命令提示符下的Spring Boot CLI bin目录并运行命令spring --version以确保正确安装了spring CLI。 执行命令后，可以看到spring CLI版本，如下所示 -

使用Groovy运行Hello World

创建一个包含Rest Endpoint脚本的简单groovy文件：hello.groovy，并使用spring boot CLI运行groovy文件。代码如下所示 -

@Controller
class Example {
   @RequestMapping("/")
   @ResponseBody
   public String hello() {
      "Hello Spring Boot"
   }
}

请注意，在这个示例中，已经配置Spring Boot CLI bin目录到系统环境变量，并把文件：hello.groovy保存到D:/worksp/springboot/目录。使用命令spring run hello.groovy运行应用程序，如下面所示 -

D:\worksp\springboot>spring run hello.groovy

执行结果如下所示：

D:\worksp\springboot>spring run hello.groovy

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.5.RELEASE)

2018-09-26 09:34:13.782  INFO 13908 --- [       runner-0] o.s.boot.SpringApplication               : Starting application on DESKTOP-CAN8JLM with PID 13908 (started by hema in D:\worksp\springboot)
2018-09-26 09:34:13.810  INFO 13908 --- [       runner-0] o.s.boot.SpringApplication               : No active profile set, falling back to default profiles: default
2018-09-26 09:34:14.747  INFO 13908 --- [       runner-0] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@2ec39a62: startup date [Wed Sep 26 09:34:14 CST 2018]; root of context hierarchy
2018-09-26 09:34:18.655  INFO 13908 --- [       runner-0] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2018-09-26 09:34:18.735  INFO 13908 --- [       runner-0] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-09-26 09:34:18.736  INFO 13908 --- [       runner-0] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.34
2018-09-26 09:34:18.756  INFO 13908 --- [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: [C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\PuTTY\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\WINDOWS\System32\OpenSSH\;D:\wamp\bin\php\php7.0.29;C:\Program Files (x86)\nodejs\;D:\software\spring-2.0.5.RELEASE\bin;D:\Program Files\Python3\Scripts\;D:\Program Files\Python3\;C:\Users\hema\AppData\Local\Microsoft\WindowsApps;C:\Users\hema\AppData\Roaming\npm;.]
2018-09-26 09:34:19.030  INFO 13908 --- [ost-startStop-1] org.apache.catalina.loader.WebappLoader  : Unknown loader org.springframework.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader@24ef272d class org.springframework.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader
2018-09-26 09:34:19.140  INFO 13908 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-09-26 09:34:19.140  INFO 13908 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 4398 ms
2018-09-26 09:34:19.303  INFO 13908 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/]
2018-09-26 09:34:19.311  INFO 13908 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-09-26 09:34:19.318  INFO 13908 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-09-26 09:34:19.320  INFO 13908 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-09-26 09:34:19.322  INFO 13908 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-09-26 09:34:19.556  INFO 13908 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-26 09:34:19.831  INFO 13908 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@2ec39a62: startup date [Wed Sep 26 09:34:14 CST 2018]; root of context hierarchy
2018-09-26 09:34:19.998  INFO 13908 --- [       runner-0] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String Example.hello()
2018-09-26 09:34:20.004  INFO 13908 --- [       runner-0] 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)
2018-09-26 09:34:20.006  INFO 13908 --- [       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.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-09-26 09:34:20.050  INFO 13908 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-26 09:34:20.053  INFO 13908 --- [       runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-26 09:34:20.651  INFO 13908 --- [       runner-0] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-09-26 09:34:20.821  INFO 13908 --- [       runner-0] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-09-26 09:34:20.830  INFO 13908 --- [       runner-0] o.s.boot.SpringApplication               : Started application in 9.092 seconds (JVM running for 15.353)

运行groovy文件，所需的依赖项将自动下载，它将在Tomcat 8080端口启动应用程序，如下面给出的屏幕截图所示 -
Tomcat启动后，转到Web浏览器并点击URL => http://localhost:8080/，可以看到输出，如图所示: