springboot的简单案例一

JCHJ-131

总结

从字面理解，Boot是引导的意思，因此SpringBoot帮助开发者快速搭建Spring框架；

SpringBoot帮助开发者快速启动一个Web容器；

SpringBoot继承了原有Spring框架的优秀基因；

SpringBoot简化了使用Spring的过程。

SpringBoot使编码变简单，使配置变简单，使部署变简单，使监控变简单

 

 

下面正式开始！！！快速入门！！！

1、构建Maven项目

（1）访问 http://start.spring.io/，填写信息，选择版本

 

（2）点击 Switch to the full version

 

（3）选择适合的 Java Version

 

（4）点击 Generate Project，下载项目，可以得到项目压缩包

（5）解压项目压缩包，然后Import

 

完整的项目结构（除了controller包是下面第2步手动建的之外，其他都是下载后就有的）

 

打开pom.xml，可以看到下列代码

复制代码
<?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.lmei</groupId>
<artifactId>SpringBoot01</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>SpringBoot01</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.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>1.7</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-tomcat</artifactId>
<scope>provided</scope>
</dependency>


<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
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Import项目后，如果pom.xml报错，重新保存，让它重新加载。

加载成功后，pom.xml不再报错，但项目报错“Could not calculate build plan..."

右键项目->Maven->Update Project Configuration

 

 

2、测试

新建一个HelloController.java

复制代码
package com.lmei.SpringBoot01.controller;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
@EnableAutoConfiguration
public class HelloController {
 @RequestMapping("/hello")
@ResponseBody
public String home() {
return "Hello ,spring boot!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(HelloController.class, args);
//运行之后在浏览器中访问：http://localhost:8080/hello
 }
}
复制代码

 

运行，HelloController右键->Run As->Java Application

控制台输出：

复制代码
 . ____ _ __ _ _
/\\ / ___\'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | \'_ | \'_| | \'_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
\' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.4.RELEASE)
2017-07-22 20:10:59.840 INFO 6484 --- [ main] c.l.S.controller.HelloController : Starting HelloController on USER-PC with PID 6484 (D:\workspace_spring\SpringBoot01\target\classes started by USER in D:\workspace_spring\SpringBoot01)
2017-07-22 20:10:59.840 INFO 6484 --- [ main] c.l.S.controller.HelloController : No active profile set, falling back to default profiles: default
2017-07-22 20:10:59.902 INFO 6484 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@524b19: startup date [Sat Jul 22 20:10:59 CST 2017]; root of context hierarchy
2017-07-22 20:11:01.961 INFO 6484 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-07-22 20:11:01.977 INFO 6484 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2017-07-22 20:11:01.977 INFO 6484 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.15
2017-07-22 20:11:02.196 INFO 6484 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-07-22 20:11:02.196 INFO 6484 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2294 ms
2017-07-22 20:11:02.446 INFO 6484 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: \'dispatcherServlet\' to [/]
2017-07-22 20:11:02.462 INFO 6484 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: \'characterEncodingFilter\' to: [/*]
2017-07-22 20:11:02.462 INFO 6484 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: \'hiddenHttpMethodFilter\' to: [/*]
2017-07-22 20:11:02.462 INFO 6484 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: \'httpPutFormContentFilter\' to: [/*]
2017-07-22 20:11:02.462 INFO 6484 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: \'requestContextFilter\' to: [/*]
2017-07-22 20:11:02.898 INFO 6484 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@524b19: startup date [Sat Jul 22 20:10:59 CST 2017]; root of context hierarchy
2017-07-22 20:11:03.008 INFO 6484 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto java.lang.String com.lmei.SpringBoot01.controller.HelloController.home()
2017-07-22 20:11:03.008 INFO 6484 --- [ 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)
2017-07-22 20:11:03.008 INFO 6484 --- [ 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)
2017-07-22 20:11:03.071 INFO 6484 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-07-22 20:11:03.071 INFO 6484 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-07-22 20:11:03.133 INFO 6484 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-07-22 20:11:03.352 INFO 6484 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2017-07-22 20:11:03.445 INFO 6484 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-07-22 20:11:03.445 INFO 6484 --- [ main] c.l.S.controller.HelloController : Started HelloController in 4.137 seconds (JVM running for 4.651)
2017-07-22 20:14:39.768 INFO 6484 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring FrameworkServlet \'dispatcherServlet\'
2017-07-22 20:14:39.769 INFO 6484 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet \'dispatcherServlet\': initialization started
2017-07-22 20:14:39.819 INFO 6484 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet \'dispatcherServlet\': initialization completed in 50 ms
复制代码

 

然后在浏览器访问：http://localhost:8080/hello

 

运行时，可能会出现的错误

unable to start embedded container; nested exception is java.lang.NoSuchMethodError: 
org.apache.tomcat.util.scan.StandardJarScanner.setJarScanFilter(Lorg/apache/tomcat/JarScanFilter;

完整的错误信息如下：

复制代码
org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is java.lang.NoSuchMethodError: org.apache.tomcat.util.scan.StandardJarScanner.setJarScanFilter(Lorg/apache/tomcat/JarScanFilter;)V
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) ~[spring-context-4.3.9.RELEASE.jar:4.3.9.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at com.lmei.SpringBoot01.controller.HelloController.main(HelloController.java:20) [classes/:na]
Caused by: java.lang.NoSuchMethodError: org.apache.tomcat.util.scan.StandardJarScanner.setJarScanFilter(Lorg/apache/tomcat/JarScanFilter;)V
at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner$Tomcat8TldSkipSetter.setSkipPattern(SkipPatternJarScanner.java:106) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner.setPatternToTomcat8SkipFilter(SkipPatternJarScanner.java:61) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner.<init>(SkipPatternJarScanner.java:56) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.tomcat.SkipPatternJarScanner.apply(SkipPatternJarScanner.java:87) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.prepareContext(TomcatEmbeddedServletContainerFactory.java:209) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:178) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:164) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:134) ~[spring-boot-1.5.4.RELEASE.jar:1.5.4.RELEASE]
... 8 common frames omitted
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出错的原因是因为配置的时候不小心把tomcat配置进去，去掉就可以

 

 

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