springBoot 入门（一）—— 使用idea创建第一个springBoot项目
时间:2022-07-25
本文章向大家介绍springBoot 入门（一）—— 使用idea创建第一个springBoot项目，主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项，具有一定的参考价值，需要的朋友可以参考一下。
版本使用说明
idea 为 Idea 2017 jdk 采用1.8 maven 采用 3.5.3
创建项目
配置pom依赖的包，然后更新依赖包，pom.xml内容如下：
<?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.wq</groupId>
<artifactId>beauty</artifactId>
<version>1.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>一般刚写了pom.xml会出现如下报错
其中, spring-boot-starter-web是支持web的模块, spring-boot-starter-test是支持测试的模块.
这时候需要 配置 idea 的 maven 配置
等待引用后，之后就不会报错
配置resources下面的Web资源文件，这里我就配置两个文件，一个是用来存放静态文件夹的static文件，还有一个就是用来存放HTML的资源文件夹templates。这里需要特别主要的是：static文件中一般存放css，js，image等静态资源文件，而templates文件中一般存放各种HTML文件。而且这两个文件都是默认存在的，路径不需要特别的配置就可以直接引用了。aplication.properties是个配置文件，这里面可以配置SpringBoot的相关信息。大家需要注意的是这个文件名千万不要写错，也不要放错位置，不然都不会生效的。书写springBoot入口函数和springMVC控制器测试
DemoApplication.java
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}HelloController.java 如果使用@RestController表示里边的方法都以json格式输出, 无需再添加额外的json配置，此时此处并没有使用。
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HelloController {
@RequestMapping("/index")
public String index(){
return "welcome";
}
} csstest.css
body {
padding: 0px;
margin: auto;
font-family: "黑体", "仿宋", Arial, "Arial Unicode MS", System;
background-color: #00F;
font-size: 20px;
text-align: left;
}welcome.html
<html>
<head>
<title>Title</title>
</head>
<link href="css/csstest.css" rel="stylesheet"/>
<body>
<p>welcome page is login.........</p>
</body>
</html>application.properties
#修改tomcat的默认的端口号，将8080改为8888
server.port=8888 在DemoApplication页面右击然后run。
注意这个运行时不是用的tomcat，而是直接用的application，(使用的是其内嵌默认的tomcat，而不是我配置的 )
看到如下日志，说明快成功了
然而，有没有看到
** WARNING ** : Your ApplicationContext is unlikely to start due to a @ComponentScan of the default package.你不太可能成功，因为没有默认包！ 新建默认包，后如下
再次启动，看到如下，则说明你的 spring boot hello world 已经成功
D:jdk1.8binjava "-javaagent:C:Program FilesJetBrainsIntelliJ IDEA Community Edition 2017.2.6libidea_rt.jar=62993:C:Program FilesJetBrainsIntelliJ IDEA Community Edition 2017.2.6bin" -Dfile.encoding=UTF-8 -classpath D:jdk1.8jrelibcharsets.jar;D:jdk1.8jrelibdeploy.jar;D:jdk1.8jrelibextaccess-bridge-64.jar;D:jdk1.8jrelibextcldrdata.jar;D:jdk1.8jrelibextdnsns.jar;D:jdk1.8jrelibextjaccess.jar;D:jdk1.8jrelibextjfxrt.jar;D:jdk1.8jrelibextlocaledata.jar;D:jdk1.8jrelibextnashorn.jar;D:jdk1.8jrelibextsunec.jar;D:jdk1.8jrelibextsunjce_provider.jar;D:jdk1.8jrelibextsunmscapi.jar;D:jdk1.8jrelibextsunpkcs11.jar;D:jdk1.8jrelibextzipfs.jar;D:jdk1.8jrelibjavaws.jar;D:jdk1.8jrelibjce.jar;D:jdk1.8jrelibjfr.jar;D:jdk1.8jrelibjfxswt.jar;D:jdk1.8jrelibjsse.jar;D:jdk1.8jrelibmanagement-agent.jar;D:jdk1.8jrelibplugin.jar;D:jdk1.8jrelibresources.jar;D:jdk1.8jrelibrt.jar;D:Userszhangqi975workspacebeautytargetclasses;D:mavenlocalrepoorgspringframeworkbootspring-boot-starter-web1.4.0.RELEASEspring-boot-starter-web-1.4.0.RELEASE.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot-starter1.4.0.RELEASEspring-boot-starter-1.4.0.RELEASE.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot1.4.0.RELEASEspring-boot-1.4.0.RELEASE.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot-autoconfigure1.4.0.RELEASEspring-boot-autoconfigure-1.4.0.RELEASE.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot-starter-logging1.4.0.RELEASEspring-boot-starter-logging-1.4.0.RELEASE.jar;D:mavenlocalrepochqoslogbacklogback-classic1.1.7logback-classic-1.1.7.jar;D:mavenlocalrepochqoslogbacklogback-core1.1.7logback-core-1.1.7.jar;D:mavenlocalrepoorgslf4jjcl-over-slf4j1.7.21jcl-over-slf4j-1.7.21.jar;D:mavenlocalrepoorgslf4jjul-to-slf4j1.7.21jul-to-slf4j-1.7.21.jar;D:mavenlocalrepoorgslf4jlog4j-over-slf4j1.7.21log4j-over-slf4j-1.7.21.jar;D:mavenlocalrepoorgyamlsnakeyaml1.17snakeyaml-1.17.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot-starter-tomcat1.4.0.RELEASEspring-boot-starter-tomcat-1.4.0.RELEASE.jar;D:mavenlocalrepoorgapachetomcatembedtomcat-embed-core8.5.4tomcat-embed-core-8.5.4.jar;D:mavenlocalrepoorgapachetomcatembedtomcat-embed-el8.5.4tomcat-embed-el-8.5.4.jar;D:mavenlocalrepoorgapachetomcatembedtomcat-embed-websocket8.5.4tomcat-embed-websocket-8.5.4.jar;D:mavenlocalrepoorghibernatehibernate-validator5.2.4.Finalhibernate-validator-5.2.4.Final.jar;D:mavenlocalrepojavaxvalidationvalidation-api1.1.0.Finalvalidation-api-1.1.0.Final.jar;D:mavenlocalrepoorgjbossloggingjboss-logging3.3.0.Finaljboss-logging-3.3.0.Final.jar;D:mavenlocalrepocomfasterxmlclassmate1.3.1classmate-1.3.1.jar;D:mavenlocalrepocomfasterxmljacksoncorejackson-databind2.8.1jackson-databind-2.8.1.jar;D:mavenlocalrepocomfasterxmljacksoncorejackson-annotations2.8.1jackson-annotations-2.8.1.jar;D:mavenlocalrepocomfasterxmljacksoncorejackson-core2.8.1jackson-core-2.8.1.jar;D:mavenlocalrepoorgspringframeworkspring-web4.3.2.RELEASEspring-web-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkspring-aop4.3.2.RELEASEspring-aop-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkspring-beans4.3.2.RELEASEspring-beans-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkspring-context4.3.2.RELEASEspring-context-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkspring-webmvc4.3.2.RELEASEspring-webmvc-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkspring-expression4.3.2.RELEASEspring-expression-4.3.2.RELEASE.jar;D:mavenlocalrepoorgslf4jslf4j-api1.7.21slf4j-api-1.7.21.jar;D:mavenlocalrepoorgspringframeworkspring-core4.3.2.RELEASEspring-core-4.3.2.RELEASE.jar;D:mavenlocalrepoorgspringframeworkbootspring-boot-starter-thymeleaf1.4.0.RELEASEspring-boot-starter-thymeleaf-1.4.0.RELEASE.jar;D:mavenlocalrepoorgthymeleafthymeleaf-spring42.1.5.RELEASEthymeleaf-spring4-2.1.5.RELEASE.jar;D:mavenlocalrepoorgthymeleafthymeleaf2.1.5.RELEASEthymeleaf-2.1.5.RELEASE.jar;D:mavenlocalrepoognlognl3.0.8ognl-3.0.8.jar;D:mavenlocalrepoorgjavassistjavassist3.20.0-GAjavassist-3.20.0-GA.jar;D:mavenlocalrepoorgunbescapeunbescape1.1.0.RELEASEunbescape-1.1.0.RELEASE.jar;D:mavenlocalreponznetultraqthymeleafthymeleaf-layout-dialect1.4.0thymeleaf-layout-dialect-1.4.0.jar;D:mavenlocalrepoorgcodehausgroovygroovy2.4.7groovy-2.4.7.jar HelloWord.DemoApplication
. ____ _ __ _ _
/\ / ___'_ __ _ _(_)_ __ __ _
( ( )___ | '_ | '_| | '_ / _` |
\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |___, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.4.0.RELEASE)
2018-04-11 18:11:08.824 INFO 8904 --- [ main] HelloWord.DemoApplication : Starting DemoApplication on IQSZ-L3025 with PID 8904 (D:Userszhangqi975workspacebeautytargetclasses started by ZHANGQI975 in D:Userszhangqi975workspacebeauty)
2018-04-11 18:11:08.828 INFO 8904 --- [ main] HelloWord.DemoApplication : No active profile set, falling back to default profiles: default
2018-04-11 18:11:09.840 INFO 8904 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@3f197a46: startup date [Wed Apr 11 18:11:09 CST 2018]; root of context hierarchy
2018-04-11 18:11:15.126 INFO 8904 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8888 (http)
2018-04-11 18:11:15.155 INFO 8904 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
2018-04-11 18:11:15.157 INFO 8904 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.4
2018-04-11 18:11:15.431 INFO 8904 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-04-11 18:11:15.431 INFO 8904 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 5596 ms
2018-04-11 18:11:15.751 INFO 8904 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2018-04-11 18:11:15.763 INFO 8904 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-04-11 18:11:15.763 INFO 8904 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-04-11 18:11:15.764 INFO 8904 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-04-11 18:11:15.764 INFO 8904 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-04-11 18:11:16.335 INFO 8904 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@3f197a46: startup date [Wed Apr 11 18:11:09 CST 2018]; root of context hierarchy
2018-04-11 18:11:16.464 INFO 8904 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/index]}" onto public java.lang.String HelloWord.HelloController.index()
2018-04-11 18:11:16.470 INFO 8904 --- [ 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)
2018-04-11 18:11:16.470 INFO 8904 --- [ 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)
2018-04-11 18:11:16.517 INFO 8904 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-11 18:11:16.517 INFO 8904 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-11 18:11:16.596 INFO 8904 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-04-11 18:11:17.792 INFO 8904 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-04-11 18:11:18.593 INFO 8904 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8888 (http)
2018-04-11 18:11:18.600 INFO 8904 --- [ main] HelloWord.DemoApplication : Started DemoApplication in 10.957 seconds (JVM running for 12.28)打开浏览器，输入： http://localhost:8888/index 出现
则说明成功。
为了证明spring boot 的热部署性，更改DemoApplication.java文件
为
package HelloWord;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
System.out.println("spring boot 启动成功！");
}
}如果再次启动时候，没有停止，那么会报错如下
停止后，再次启动， 查看日志：
关于停止spring boot 内部的Tomcat 有两种方式
- 第一种：借用idea功能
- 第二种，优雅的方式
Maven 增加依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency>配置文件application.properties配置启用shutdown的HTTP访问
#启用 shutdown endpoint的HTTP访问 endpoints.shutdown.enabled=true #不需要用户名密码验证 endpoints.shutdown.sensitive=false 此时，配置文件如下：
#修改tomcat的默认的端口号，将8080改为8888
server.port=8888
#启用shutdown endpoint的HTTP访问
endpoints.shutdown.enabled=true
#不需要用户名密码验证
endpoints.shutdown.sensitive=falsePOST请求到shutdown路径 以上配置完成后，可以使用curl -X POST localhost:port/shutdown发动post请求，即可优雅的停止应用。 如果使用Linux：
curl -X POST localhost:8888/manage/shutdown
{"message":"Shutting down, bye..."}如果使用Windows 则直接在浏览器中输入
http://localhost:8888/shutdown但是报错，
因为 这个是以post请求有效的。 Get请求不支持 后台也同样报错
所以，这条路走不通了（暂时走不通，将来如果发现，或者聪明的你知道，请留言）
至此，spring boot 版本的Hello world 完毕！
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