Springboot快速入门

Springboot快速入门

简介

在您第1次接触和学习Spring框架的时候，是否因为其繁杂的配置而退却了？在你第n次使用Spring框架的时候，是否觉得一堆反复黏贴的配置有一些厌烦？那么您就不妨来试试使用Spring Boot来让你更易上手，更简单快捷地构建Spring应用！

Spring Boot让我们的Spring应用变的更轻量化。比如：你可以仅仅依靠一个Java类来运行一个Spring引用。你也可以打包你的应用为jar并通过使用java -jar来运行你的Spring Web应用。

Spring Boot的主要优点：

• 为所有Spring开发者更快的入门
• 开箱机用，提供各种默认配置来简化项目配置
• 内嵌式容器，简化web项目
• 没有冗余代码生成和XML配置的要求

---

快速入门

本章主要目标完成Spring Boot基础项目的构建，并且实现一个简单的Http请求处理，通过这个例子对Spring Boot有一个初步的了解，并体验其结构简单、开发快速的特性。

系统要求

Java 7及以上
Spring Framework 4.1.5及以上
本文采用Java 1.8.0_73、Spring Boot 1.5.8调试通过。

使用Maven构建项目

• 1.通过SPRING INITIALIZR工具产生基础项目
  • 1.访问：http://start.spring.io/
  • 2.选择构建工具Maven Project、Spring Boot版本1.3.2以及一些工程基本信息，可参考下图所示SPRING INITIALIZR
    SPRING INITIALIZR
  • 3.点击Generate Project下载项目压缩包
• 2.解压项目包，并用IDE以Maven项目导入，以IntelliJ IDEA 14为例：
  • 1.菜单中选择File–>New–>Project from Existing Sources...
  • 2.选择解压后的项目文件夹，点击OK
  • 3.点击Import project from external model并选择Maven，点击Next到底为止。
  • 4.若你的环境有多个版本的JDK，注意到选择Java SDK的时候请选择Java 7以上的版本

项目结构解析

[图片上传失败...(image-e4796c-1510299088962)]

通过上面步骤完成了基础项目的创建，如上图所示，SpringBoot的基础结构共三个文件（具体路径根据用户生成项目时填写的Group所有差异）：

• src/main/java下的程序入口：SpringbootdemoApplication
• src/main/resources下的配置文件：application.properties
• src/test/下的测试入口：SpringbootdemoApplicationTests

生成的SpringbootdemoApplication和SpringbootdemoApplicationTests类都可以直接运行来启动当前创建的项目，由于目前该项目未配合任何数据访问或Web模块，程序会在加载完Spring之后结束运行。

引入Web模块

当前的pom.xml内容如下，仅引入了两个模块：

• spring-boot-starter：核心模块，包括自动配置支持、日志和YAML
• spring-boot-starter-test：测试模块，包括JUnit、Hamcrest、Mockito

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

引入Web模块Web模块，需添加spring-boot-starter-web模块：

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

编写Hello服务

• 创建HelloController类，内容如下：

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String test(){
        return "hello springboot";
    }
}

• 启动主程序，输入部分日志如下：

      .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.8.RELEASE)

2017-11-10 14:41:25.956  INFO 5186 --- [           main] c.z.s.d.s.SpringbootdemoApplication      : Starting SpringbootdemoApplication on zzydeMBP with PID 5186 (/Users/zzy/Documents/zzy/Idea_workspace/springboot_learn/springbootdemo/target/classes started by zzy in /Users/zzy/Documents/zzy/Idea_workspace/springboot_learn/springbootdemo1)
2017-11-10 14:41:25.961  INFO 5186 --- [           main] c.z.s.d.s.SpringbootdemoApplication      : No active profile set, falling back to default profiles: default
2017-11-10 14:41:26.028  INFO 5186 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@7ff2a664: startup date [Fri Nov 10 14:41:26 CST 2017]; root of context hierarchy
2017-11-10 14:41:27.138  INFO 5186 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-11-10 14:41:27.149  INFO 5186 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2017-11-10 14:41:27.150  INFO 5186 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.23
2017-11-10 14:41:27.230  INFO 5186 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2017-11-10 14:41:27.230  INFO 5186 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1206 ms
2017-11-10 14:41:27.314  INFO 5186 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2017-11-10 14:41:27.317  INFO 5186 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-11-10 14:41:27.317  INFO 5186 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-11-10 14:41:27.318  INFO 5186 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-11-10 14:41:27.318  INFO 5186 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2017-11-10 14:41:27.564  INFO 5186 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@7ff2a664: startup date [Fri Nov 10 14:41:26 CST 2017]; root of context hierarchy
2017-11-10 14:41:27.602  INFO 5186 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto public java.lang.String com.zzy.springboot.demo.springbootdemo.controller.HelloController.test()
2017-11-10 14:41:27.605  INFO 5186 --- [           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.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-11-10 14:41:27.605  INFO 5186 --- [           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.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-11-10 14:41:27.622  INFO 5186 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 14:41:27.622  INFO 5186 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 14:41:27.642  INFO 5186 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 14:41:27.729  INFO 5186 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-11-10 14:41:27.775  INFO 5186 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-11-10 14:41:27.781  INFO 5186 --- [           main] c.z.s.d.s.SpringbootdemoApplication      : Started SpringbootdemoApplication in 2.131 seconds (JVM running for 3.001)
2017-11-10 14:42:09.029  INFO 5186 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2017-11-10 14:42:09.029  INFO 5186 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2017-11-10 14:42:09.045  INFO 5186 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 16 ms

• 打开浏览器访问http://localhost:8080/hello，可以看到页面输出hello springboot
  [图片上传失败...(image-8c79ef-1510299088962)]