文章目录

• 环境准备
• 第一步:创建一个Maven程序
• 第二步:导入SpringBoot相关依赖
• 第三步:编写主程序
• 第四步:编写Controller
• 第五步:将程序跑起来
• 第六步:简化部署

第一个Spring Boot实现的功能：
浏览器发送hello请求，服务器接收请求并处理，响应"HelloWorld!"字符串。

环境准备

第一步:创建一个Maven程序

IDEA整合Maven

创建Maven程序

第二步:导入SpringBoot相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.gql</groupId>
<artifactId>springboot-01-helloworld</artifactId>
<version>1.0-SNAPSHOT</version>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>

</project>

可以看到，此时已经自动导入了相关的jar包

第三步:编写主程序

• @SpringBootApplication： 是一个复合注解，使用该注解告诉Springboot启用自动配置和组件扫描功能。
• SpringApplication.run(HelloWorld.class, args); ：将Spring应用启动起来。

package com.gql;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
* Class description:
* 		主程序中启动SpringBoot
* @guoqianliang
*/
@SpringBootApplication
public class HelloWorld {
public static void main(String[] args) {
SpringApplication.run(HelloWorld.class, args);
}
}

第四步:编写Controller

• @RequestMapping("/hello")：接收浏览器的hello请求。
• @ResponseBody：将"Hello World!"写给浏览器

package com.gql.Controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
* Class description:
* 		Controller控制器
* @guoqianliang
*/
@Controller
public class HelloController {
@ResponseBody
@RequestMapping("/hello")
public String hello() {
return "Hello World!";
}
}

第五步:将程序跑起来

主程序运行Main方法后直接在浏览器访问(Springboot内置了tomcat容器)：

项目工程结构如下:

第六步:简化部署

在pom中添加pom插件后，在Maven选项卡中双击package即可一键打包成jar，在dos中可以直接java -jar进行执行。

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

可以在控制台找到文件打包后放置的位置：

[INFO] Building jar: D:\Program Files\JAVA\workspace_idea\springboot01helloworld\target\springboot-01-helloworld-1.0-SNAPSHOT.jar

也可以在IDEA中直接看到自动生成的jar包

将此jar包copy到桌面，运行dos命令，执行jar包：

• java -jar springboot-01-helloworld-1.0-SNAPSHOT.jar

Microsoft Windows [版本 10.0.18363.720]
(c) 2019 Microsoft Corporation。保留所有权利。

C:\Users\Hudie>C:\Users\Hudie\Desktop
'C:\Users\Hudie\Desktop' 不是内部或外部命令，也不是可运行的程序
或批处理文件。

C:\Users\Hudie>cd C:\Users\Hudie\Desktop

C:\Users\Hudie\Desktop>java -jar springboot-01-helloworld-1.0-SNAPSHOT.jar

.   ____          _            __ _ _
/\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/  ___)| |_)| | | | | || (_| |  ) ) ) )
'  |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot ::        (v1.5.4.RELEASE)

2020-03-21 12:10:53.952  INFO 12048 --- [           main] com.gql.HelloWorld                       : Starting HelloWorld v1.0-SNAPSHOT on LAPTOP-EPI7POB8 with PID 12048 (C:\Users\Hudie\Desktop\springboot-01-helloworld-1.0-SNAPSHOT.jar started by Hudie in C:\Users\Hudie\Desktop)
2020-03-21 12:10:53.956  INFO 12048 --- [           main] com.gql.HelloWorld                       : No active profile set, falling back to default profiles: default
2020-03-21 12:10:54.023  INFO 12048 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@30946e09: startup date [Sat Mar 21 12:10:54 CST 2020]; root of context hierarchy
2020-03-21 12:10:55.958  INFO 12048 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2020-03-21 12:10:56.006  INFO 12048 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-03-21 12:10:56.011  INFO 12048 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.15
2020-03-21 12:10:56.271  INFO 12048 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-03-21 12:10:56.271  INFO 12048 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 2250 ms
2020-03-21 12:10:56.514  INFO 12048 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2020-03-21 12:10:56.522  INFO 12048 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2020-03-21 12:10:56.523  INFO 12048 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2020-03-21 12:10:56.523  INFO 12048 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2020-03-21 12:10:56.523  INFO 12048 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2020-03-21 12:10:57.084  INFO 12048 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@30946e09: startup date [Sat Mar 21 12:10:54 CST 2020]; root of context hierarchy
2020-03-21 12:10:57.200  INFO 12048 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto public java.lang.String com.gql.Controller.HelloController.hello()
2020-03-21 12:10:57.206  INFO 12048 --- [           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)
2020-03-21 12:10:57.206  INFO 12048 --- [           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)
2020-03-21 12:10:57.240  INFO 12048 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2020-03-21 12:10:57.240  INFO 12048 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2020-03-21 12:10:57.292  INFO 12048 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2020-03-21 12:10:57.518  INFO 12048 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2020-03-21 12:10:57.631  INFO 12048 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2020-03-21 12:10:57.637  INFO 12048 --- [           main] com.gql.HelloWorld                       : Started HelloWorld in 4.025 seconds (JVM running for 4.416)
2020-03-21 12:11:06.815  INFO 12048 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2020-03-21 12:11:06.815  INFO 12048 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2020-03-21 12:11:06.837  INFO 12048 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 20 ms

此时项目就启动了，可以在浏览器直接访问了。

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