Spring Boot CLI（Command Line Interface）是一個命令行工具，您可以用它來快速構建Spring原型應用。通過Spring Boot CLI，我們可以通過編寫Groovy腳本來快速的構建出Spring Boot應用，并通過命令行的方式將其運行起來。下來，我們來學習一下如何安裝和使用Spring Boot CLI。
#安裝Spring Boot CLI
關于Spring Boot CLI的安裝方式有很多，這里根據目前主要主流的開發平臺，具體介紹一下Windows和Mac下的安裝方式：
#通用安裝
先介紹一個所有平臺都可以使用的安裝方法。
第一步：下載Spring Boot CLI的工具包：
- spring-boot-cli-2.0.1.RELEASE-bin.zipopen in new window
- spring-boot-cli-2.0.1.RELEASE-bin.tar.gzopen in new window
第二步：解壓下載內容，可以看到bin目錄下已經有適用于windows和linux平臺的兩個可執行文件了，我們已經可以直接使用它；為了更方便的使用Spring Boot CLI的命令，我們可以將上面bin目錄中對應的可執行文件加入到當前系統的環境變量即可。
#Mac OSX Brew安裝
在Mac OSX系統下面就非常方便了，我們可以通過Brew來進行安裝，只需要分別執行下面的兩條的命令即可：
$ brew tap pivotal/tap
$ brew install springboot
#驗證安裝
不論使用哪種方法安裝，在安裝好之后，我們可以通過下面的命令來驗證一下當前的安裝結果：
$ spring --version
Spring CLI v2.0.0.RELEASE#運行Groovy腳本
在完成了Spring Boot CLI的安裝之后，我們來試試使用它來快速的構建一個Spring Boot應用，方法很簡單，只需要如下操作：
第一步：新建一個Groovy腳本，hello.groovy，內容如下：
@RestController
class ThisWillActuallyRun {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
第二步：使用spring命令運行該Groovy腳本，具體如下：
$ spring run hello.groovy
Resolving dependencies...............................................
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2018-04-04 18:11:20.571 INFO 70477 --- [ runner-0] o.s.boot.SpringApplication : Starting application on zhaiyongchaodeMacBook-Pro.local with PID 70477 (started by zhaiyongchao in /Users/zhaiyongchao/Downloads)
2018-04-04 18:11:20.574 INFO 70477 --- [ runner-0] o.s.boot.SpringApplication : No active profile set, falling back to default profiles: default
2018-04-04 18:11:20.732 INFO 70477 --- [ runner-0] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@3c3ad454: startup date [Wed Apr 04 18:11:20 CST 2018]; root of context hierarchy
2018-04-04 18:11:21.758 INFO 70477 --- [ runner-0] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2018-04-04 18:11:21.783 INFO 70477 --- [ runner-0] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-04-04 18:11:21.784 INFO 70477 --- [ runner-0] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.28
2018-04-04 18:11:21.795 INFO 70477 --- [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: [/Users/zhaiyongchao/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2018-04-04 18:11:21.849 INFO 70477 --- [ost-startStop-1] org.apache.catalina.loader.WebappLoader : Unknown loader org.springframework.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader@5e3b901 class org.springframework.boot.cli.compiler.ExtendedGroovyClassLoader$DefaultScopeParentClassLoader
2018-04-04 18:11:21.884 INFO 70477 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-04-04 18:11:21.885 INFO 70477 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1153 ms
2018-04-04 18:11:22.042 INFO 70477 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-04-04 18:11:22.049 INFO 70477 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-04-04 18:11:22.049 INFO 70477 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-04-04 18:11:22.049 INFO 70477 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-04-04 18:11:22.049 INFO 70477 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-04-04 18:11:22.391 INFO 70477 --- [ runner-0] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@3c3ad454: startup date [Wed Apr 04 18:11:20 CST 2018]; root of context hierarchy
2018-04-04 18:11:22.489 INFO 70477 --- [ runner-0] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String ThisWillActuallyRun.home()
2018-04-04 18:11:22.495 INFO 70477 --- [ 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)
2018-04-04 18:11:22.496 INFO 70477 --- [ 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)
2018-04-04 18:11:22.550 INFO 70477 --- [ runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-04 18:11:22.550 INFO 70477 --- [ runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-04 18:11:22.598 INFO 70477 --- [ runner-0] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-04 18:11:22.955 INFO 70477 --- [ runner-0] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-04-04 18:11:23.004 INFO 70477 --- [ runner-0] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2018-04-04 18:11:23.010 INFO 70477 --- [ runner-0] o.s.boot.SpringApplication : Started application in 17.605 seconds (JVM running for 79.248)
從日志中我們可以看到我們通過Groovy腳本定義的一個簡單web應用就構建成功了，可以通過訪問localhost:8080來驗證一下上面應用提供的接口：
$ curl localhost:8080
Hello World!是不是非常簡單？有木有顛覆您對Java應用的印象？
