spring boot實戰(第一篇)第一個案例

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目錄(?)[+]

 

spring boot實戰(第一篇)第一個案例

前言

寫在前面的話

一直想將spring boot相關內容寫成一個系列的博客，今天終於有時間開始了第一篇文章
之後有時間就會繼續寫下去。

spring boot 博客內容規劃

• spring boot 基本用法
• 自動配置
• 技術集成
• 性能監控
• 源碼解析

spring boot 功能強大，後面會細細道來。

第一個案例

工程的構建

構建spring boot工程通常採用兩種方式 gradle 、maven;相對於maven的pom配置gradle 更加簡單，有興趣的同窗能夠去學習下gradle，這裏採用maven。

建立一個maven工程，對應的pom.xml文件：

 1    <parent>
 2         <groupId>org.springframework.boot</groupId>
 3         <artifactId>spring-boot-starter-parent</artifactId>
 4         <version>1.2.4.RELEASE</version>
 5     </parent>
 6 
 7     <properties>
 8         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 9     </properties>
10 
11     <dependencies>
12 
13         <dependency>
14             <groupId>org.springframework.boot</groupId>
15             <artifactId>spring-boot-starter-web</artifactId>
16         </dependency>
17     </dependencies>
18 
19     <build>
20         <plugins>
21             <plugin>
22                 <groupId>org.springframework.boot</groupId>
23                 <artifactId>spring-boot-maven-plugin</artifactId>
24             </plugin>
25         </plugins>
26     </build>

 

版本採用1.2.4,非官網最新版，但屬於穩定版本

建立 Application.java

 1 package com.lkl.springboot;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 
 6 @SpringBootApplication
 7 public class Application {
 8     public static void main(String[] args) {
 9         SpringApplication.run(Application.class, args);
10     }
11 }

 

運行main方法

.   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.2.4.RELEASE) 2015-08-25 22:53:35.484 INFO 554 --- [ main] com.lkl.springboot.Application : Starting Application on mac.local with PID 554 (/Users/liaokailin/code/github/blog-springboot/target/classes started by lkl in /Users/liaokailin/code/github/blog-springboot) 2015-08-25 22:53:35.561 INFO 554 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@328908cd: startup date [Tue Aug 25 22:53:35 CST 2015]; root of context hierarchy 2015-08-25 22:53:36.395 INFO 554 --- [ main] o.s.b.f.s.DefaultListableBeanFactory : Overriding bean definition for bean 'beanNameViewResolver': replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]] 2015-08-25 22:53:37.404 INFO 554 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http) 2015-08-25 22:53:37.796 INFO 554 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat 2015-08-25 22:53:37.798 INFO 554 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.0.23 2015-08-25 22:53:37.955 INFO 554 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2015-08-25 22:53:37.955 INFO 554 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2397 ms 2015-08-25 22:53:38.813 INFO 554 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/] 2015-08-25 22:53:38.818 INFO 554 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*] 2015-08-25 22:53:38.819 INFO 554 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] 2015-08-25 22:53:39.075 INFO 554 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@328908cd: startup date [Tue Aug 25 22:53:35 CST 2015]; root of context hierarchy 2015-08-25 22:53:39.151 INFO 554 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" 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) 2015-08-25 22:53:39.151 INFO 554 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],methods=[],params=[],headers=[],consumes=[],produces=[text/html],custom=[]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest) 2015-08-25 22:53:39.180 INFO 554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2015-08-25 22:53:39.180 INFO 554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2015-08-25 22:53:39.232 INFO 554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2015-08-25 22:53:39.326 INFO 554 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup 2015-08-25 22:53:39.430 INFO 554 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http) 2015-08-25 22:53:39.433 INFO 554 --- [ main] com.lkl.springboot.Application : Started Application in 4.829 seconds (JVM running for 5.238) 

 

spring boot已經啓動，內嵌tomcat容器，監聽爲8080端口

就是這麼簡單，一個spring boot 的程序就建立了。

@SpringBootApplication 註解

SpringBootApplication註解源碼以下：

 1 @Target(ElementType.TYPE)
 2 @Retention(RetentionPolicy.RUNTIME)
 3 @Documented
 4 @Inherited
 5 @Configuration
 6 @EnableAutoConfiguration
 7 @ComponentScan
 8 public @interface SpringBootApplication {
 9 
10     /**
11      * Exclude specific auto-configuration classes such that they will never be applied.
12      * @return the classes to exclude
13      */
14     Class<?>[] exclude() default {};
15 
16 }

 

@Configuration : 表示Application做爲sprig配置文件存在 
@EnableAutoConfiguration: 啓動spring boot內置的自動配置 
@ComponentScan : 掃描bean，路徑爲Application類所在package以及package下的子路徑，這裏爲 com.lkl.springboot，在spring boot中bean都放置在該路徑已經子路徑下。

構建REST工程

上面的操做連個HelloWorld都沒有出來，遠遠滿不足咱們的需求。

建立一個package：com.lkl.springboot.controller 保存controller

構建 HelloWorldController.java

 1  package com.lkl.springboot.controller;
 2 
 3 import org.springframework.web.bind.annotation.PathVariable;
 4 import org.springframework.web.bind.annotation.RequestMapping;
 5 import org.springframework.web.bind.annotation.RequestMethod;
 6 import org.springframework.web.bind.annotation.ResponseBody;
 7 import org.springframework.web.bind.annotation.RestController;
 8 
 9 @RestController
10 @RequestMapping("/springboot")
11 public class HelloWorldController {
12 
13     @RequestMapping(value = "/{name}", method = RequestMethod.GET)
14     public String sayWorld(@PathVariable("name") String name) {
15         return "Hello " + name;
16     }
17 }

 

再次執行 Application 而後訪問http://localhost:8080/springboot/Liaokailin

獲得結果： 
Hello Liaokailin

方法中涉及的註解就不解釋了，比較簡單～

第一個案例就到這裏。

轉載請註明 
http://blog.csdn.net/liaokailin/article/details/47988617

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