Spring Boot【1.HelloWorld】

1.使用要求
2.POM.xml
3.代码
4.打包和运行

基于版本：Spring Boot 1.5.7.RELEASE

1.使用要求

推荐java 8（1.6/1.7在Springboot 1.x.x也可以使用）、Maven (3.2+)

Spring Boot 2.0.0.BUILD-SNAPSHOT requires Java 8 and Spring Framework 5.0.0.RELEASE or above;
Explicit build support is provided for Maven (3.2+), and Gradle 4.

#查看版本
$ java -version
$ mvn -v

2.POM.xml

<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.top.test.springboot</groupId>
    <artifactId>test-springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>

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

    <!-- 用于打包成jar -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

SpringBoot提供很多Starter POM，为了简化添加jars到classpath的操作

spring-boot-starter-parent作为parent节点，提供了Maven默认设置和版本控制，所以期望(”blessed“)的依赖就可以省略version标记

spring-boot-starter-parent本身不引入任何依赖(mvn dependency:tree)

其他Starter POM也只提供开发特定类型应用所需的依赖，按需引入

spring-boot-starter-web依赖树中包括了springboot,spring-web,spring-webmvc,tomcat,jackson,hibernate-validator等

3.代码

package com.top.test.springboot;

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

@RestController//@ResponseBody + @Controller
public class HelloController {
    @RequestMapping(value="/hello")
    public String helloWorld() {
        return "hello world!";
    }
}

package com.top.test.controller;

import java.util.Arrays;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @SpringBootApplication包含: @Configuration + @ComponentScan + @EnableAutoConfiguration
 * 其中@Configuration标记为配置类;@ComponentScan默认只扫描同包/子包;@EnableAutoConfiguration开启自动配置
 */
//@SpringBootApplication
@EnableAutoConfiguration
@ComponentScan(basePackages="com.top.test")//不在同包下的要指定包
public class HelloApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class, args);
    }
    
    //检索app自动创建的或springboot自动添加的bean,排序并打印
    @Bean
    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
        final String[] beanNames = ctx.getBeanDefinitionNames();
        return new CommandLineRunner() {
            @Override
            public void run(String... args) throws Exception {
                System.out.println("Let's inspect the beans provided by Spring Boot:");
                Arrays.sort(beanNames);
                for (String beanName : beanNames) {
                    System.out.println(beanName);
                }
            }
        };
    }
}

Auto-configuration可以跟Starter POM很好的配合使用，但两者没有直接联系；Starter POM以外的jar依赖，Spring Boot仍会尽力去自动配置

main方法是应用程序入口，委托SpringBoot的SpringApplication类调用run()，启动app(包括启动被自动配置的Tomcat)

4.运行

- 1.在project目录下，命令行执行mvn spring-boot:run
- 2.借助IDE：执行main方法Run as Java Application || 配置maven build(原理同1) 
- 3.打包成jar, java -jar xxx.jar

浏览器访问:http://localhost:8080/hello

其中打包成jar运行：
借助spring-boot-maven-plugin插件（打uber/fat jar）

starter parent中有打包的配置。如果不使用spring-boot-starter-parent，就需要自己在POM.xml中配置打包项。这里使用了starter parent，只需引入spring-boot-maven-plugin插件即可

 #执行命令
$ mvn package

#生成两个文件
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building test-springboot 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ test-springboot ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ test-springboot ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ test-springboot ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ test-springboot ---
[INFO] Changes detected - recompiling the module!
[INFO] 
[INFO] --- maven-surefire-plugin:2.18.1:test (default-test) @ test-springboot ---
[INFO] 
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ test-springboot ---
[INFO] Building jar: /home/yuzhou/personalDev/workspace/test-springboot/target/test-springboot-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:1.5.7.RELEASE:repackage (default) @ test-springboot ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

另一个test-springboot-0.0.1-SNAPSHOT.jar.original是SpringBoot重新打包前,Maven创建的原始jar文件

#查看jar内容
$ jar tvf test-springboot-0.0.1-SNAPSHOT.jar

#运行jar
$ java -jar test-springboot-0.0.1-SNAPSHOT.jar 

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.7.RELEASE)

2017-10-12 18:16:27.774  INFO 12580 --- [           main] c.top.test.controller.HelloApplication   : Starting HelloApplication v0.0.1-SNAPSHOT on yuzhou with PID 12580 (/home/yuzhou/personalDev/workspace/test-springboot/target/test-springboot-0.0.1-SNAPSHOT.jar started by yuzhou in /home/yuzhou/personalDev/workspace/test-springboot/target)
2017-10-12 18:16:27.777  INFO 12580 --- [           main] c.top.test.controller.HelloApplication   : No active profile set, falling back to default profiles: default
2017-10-12 18:16:27.818  INFO 12580 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6659c656: startup date [Thu Oct 12 18:16:27 CST 2017]; root of context hierarchy
2017-10-12 18:16:28.831  INFO 12580 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-10-12 18:16:28.842  INFO 12580 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2017-10-12 18:16:28.843  INFO 12580 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.20
2017-10-12 18:16:28.912  INFO 12580 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2017-10-12 18:16:28.912  INFO 12580 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1096 ms
2017-10-12 18:16:28.997  INFO 12580 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2017-10-12 18:16:29.001  INFO 12580 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-10-12 18:16:29.001  INFO 12580 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-10-12 18:16:29.001  INFO 12580 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-10-12 18:16:29.001  INFO 12580 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2017-10-12 18:16:29.297  INFO 12580 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6659c656: startup date [Thu Oct 12 18:16:27 CST 2017]; root of context hierarchy
2017-10-12 18:16:29.368  INFO 12580 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto public java.lang.String com.top.test.springboot.HelloController.helloWorld()
2017-10-12 18:16:29.370  INFO 12580 --- [           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)
2017-10-12 18:16:29.371  INFO 12580 --- [           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)
2017-10-12 18:16:29.401  INFO 12580 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-12 18:16:29.401  INFO 12580 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-12 18:16:29.440  INFO 12580 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-12 18:16:29.539  INFO 12580 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-10-12 18:16:29.581  INFO 12580 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
Let's inspect the beans provided by Spring Boot:
basicErrorController
beanNameHandlerMapping
beanNameViewResolver
characterEncodingFilter
commandLineRunner
conventionErrorViewResolver
defaultServletHandlerMapping
defaultValidator
defaultViewResolver
dispatcherServlet
dispatcherServletRegistration
duplicateServerPropertiesDetector
embeddedServletContainerCustomizerBeanPostProcessor
error
errorAttributes
errorPageCustomizer
errorPageRegistrarBeanPostProcessor
faviconHandlerMapping
faviconRequestHandler
handlerExceptionResolver
helloApplication
helloController
hiddenHttpMethodFilter
httpPutFormContentFilter
httpRequestHandlerAdapter
jacksonObjectMapper
jacksonObjectMapperBuilder
jsonComponentModule
localeCharsetMappingsCustomizer
mappingJackson2HttpMessageConverter
mbeanExporter
mbeanServer
messageConverters
methodValidationPostProcessor
multipartConfigElement
multipartResolver
mvcContentNegotiationManager
mvcConversionService
mvcPathMatcher
mvcResourceUrlProvider
mvcUriComponentsContributor
mvcUrlPathHelper
mvcValidator
mvcViewResolver
objectNamingStrategy
org.springframework.boot.autoconfigure.AutoConfigurationPackages
org.springframework.boot.autoconfigure.condition.BeanTypeRegistry
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration
org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$Jackson2ObjectMapperBuilderCustomizerConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperBuilderConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration
org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration$DispatcherServletConfiguration
org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration
org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration
org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration$EmbeddedTomcat
org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$DefaultErrorViewResolverConfiguration
org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration
org.springframework.boot.autoconfigure.web.HttpEncodingAutoConfiguration
org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration
org.springframework.boot.autoconfigure.web.JacksonHttpMessageConvertersConfiguration
org.springframework.boot.autoconfigure.web.JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration
org.springframework.boot.autoconfigure.web.MultipartAutoConfiguration
org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration
org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration
org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration$RestTemplateConfiguration
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$EnableWebMvcConfiguration
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter$FaviconConfiguration
org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration
org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration$TomcatWebSocketConfiguration
org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor
org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.store
org.springframework.context.annotation.internalAutowiredAnnotationProcessor
org.springframework.context.annotation.internalCommonAnnotationProcessor
org.springframework.context.annotation.internalConfigurationAnnotationProcessor
org.springframework.context.annotation.internalRequiredAnnotationProcessor
org.springframework.context.event.internalEventListenerFactory
org.springframework.context.event.internalEventListenerProcessor
preserveErrorControllerTargetClassPostProcessor
propertySourcesPlaceholderConfigurer
requestContextFilter
requestMappingHandlerAdapter
requestMappingHandlerMapping
resourceHandlerMapping
restTemplateBuilder
serverProperties
simpleControllerHandlerAdapter
spring.http.encoding-org.springframework.boot.autoconfigure.web.HttpEncodingProperties
spring.http.multipart-org.springframework.boot.autoconfigure.web.MultipartProperties
spring.info-org.springframework.boot.autoconfigure.info.ProjectInfoProperties
spring.jackson-org.springframework.boot.autoconfigure.jackson.JacksonProperties
spring.mvc-org.springframework.boot.autoconfigure.web.WebMvcProperties
spring.resources-org.springframework.boot.autoconfigure.web.ResourceProperties
standardJacksonObjectMapperBuilderCustomizer
stringHttpMessageConverter
tomcatEmbeddedServletContainerFactory
viewControllerHandlerMapping
viewResolver
websocketContainerCustomizer
welcomePageHandlerMapping
2017-10-12 18:16:29.587  INFO 12580 --- [           main] c.top.test.controller.HelloApplication   : Started HelloApplication in 2.041 seconds (JVM running for 2.306)

最后编辑于：2017.12.11 02:41:37

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Spring Boot【1.HelloWorld】

1.使用要求

2.POM.xml

3.代码

4.运行

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