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spring boot实战(第一篇)第一个案例
前言
写在前面的话
一直想将spring boot相关内容写成一个系列的博客，今天终于有时间开始了第一篇文章
以后有时间就会继续写下去。
spring boot 博客内容规划
- spring boot 基本用法
- 自动配置
- 技术集成
- 性能监控
- 源码解析
spring boot 功能强大，后面会细细道来。
第一个案例
工程的构建
构建spring boot工程一般采用两种方式 gradle 、maven;相对于maven的pom配置gradle 更加简单，有兴趣的同学可以去学习下gradle，这里采用maven。
创建一个maven工程，对应的pom.xml文件：
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.4.RELEASE</version>
</parent> <properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties> <dependencies> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies> <build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
版本采用1.2.4,非官网最新版，但属于稳定版本
创建 Application.java
package com.lkl.springboot; import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
运行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已经启动，内嵌tomcat容器，监听为8080端口
就是这么简单，一个spring boot 的程序就创建了。
@SpringBootApplication 注解
SpringBootApplication注解源码如下：
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Configuration
@EnableAutoConfiguration
@ComponentScan
public @interface SpringBootApplication { /**
* Exclude specific auto-configuration classes such that they will never be applied.
* @return the classes to exclude
*/
Class<?>[] exclude() default {}; }
@Configuration: 表示Application作为sprig配置文件存在@EnableAutoConfiguration: 启动spring boot内置的自动配置@ComponentScan: 扫描bean，路径为Application类所在package以及package下的子路径，这里为com.lkl.springboot，在spring boot中bean都放置在该路径已经子路径下。
构建REST工程
上面的操作连个HelloWorld都没有出来，远远满不足我们的需求。
创建一个package：com.lkl.springboot.controller 保存controller
构建 HelloWorldController.java
package com.lkl.springboot.controller; import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController; @RestController
@RequestMapping("/springboot")
public class HelloWorldController { @RequestMapping(value = "/{name}", method = RequestMethod.GET)
public String sayWorld(@PathVariable("name") String name) {
return "Hello " + name;
}
}
再次执行 Application 然后访问http://localhost:8080/springboot/Liaokailin
得到结果： Hello Liaokailin
方法中涉及的注解就不解释了，比较简单～
第一个案例就到这里。
转载请注明
http://blog.csdn.net/liaokailin/article/details/47988617