使用Spring Boot来加速Java web项目的开发

我想，现在企业级的Java web项目应该或多或少都会使用到Spring框架的。

回首我们以前使用Spring框架的时候，我们需要首先在（如果你使用Maven的话）pom文件中增加对相关的的依赖（使用gradle来构建的话基本也一样）然后新建Spring相关的xml文件，而且往往那些xml文件还不会少。然后继续使用tomcat或者jetty作为容器来运行这个工程。基本上每次创建一个新的项目都是这么一个流程，而我们有时候仅仅想快速的创建一个Spring web工程来测试一些东西，或者是希望能节省时间。

现在我们使用Spring Boot就可以快速的做到这些了。

我们先来看一个非常简单的使用Spring boot的例子吧：

1.　　我们创建一个Maven工程，假定工程名字为spring-boot，然后我们在pom.xml文件中加入依赖：

      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
          <version>1.0.2.RELEASE</version>
      </dependency>

2.　　新建一个Controller来接受处理我们的请求：

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.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by wenchao.ren on 2014/4/26.
 */
@Controller
@EnableAutoConfiguration
public class SimpleController {

    @RequestMapping(value ="/hello", method = RequestMethod.GET)
    @ResponseBody
    public String hello(){
        return "hello world";
    }

    public static void main(String[] args) {
        SpringApplication.run(SimpleController.class, args);
    }
}

相信大家已经看到了这个Controller有一个main方法，不要急，我们直接运行这个main方法：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.0.2.RELEASE)

2014-04-26 22:54:40.985  INFO 7236 --- [           main] c.r.spring.boot.SimpleController         : Starting SimpleController on rollen with PID 7236 (D:\workspace\GitHub\SpringDemo\spring-boot\target\classes started by wenchao.ren in D:\workspace\GitHub\SpringDemo\spring-boot)
2014-04-26 22:54:41.008  INFO 7236 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@50de0926: startup date [Sat Apr 26 22:54:41 CST 2014]; root of context hierarchy
2014-04-26 22:54:41.583  INFO 7236 --- [           main] .t.TomcatEmbeddedServletContainerFactory : Server initialized with port: 8080
2014-04-26 22:54:41.706  INFO 7236 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2014-04-26 22:54:41.706  INFO 7236 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/7.0.52
2014-04-26 22:54:41.785  INFO 7236 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2014-04-26 22:54:41.785  INFO 7236 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 779 ms
2014-04-26 22:54:42.055  INFO 7236 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2014-04-26 22:54:42.057  INFO 7236 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2014-04-26 22:54:42.289  INFO 7236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-04-26 22:54:42.368  INFO 7236 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello],methods=[GET],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public java.lang.String com.rollenholt.spring.boot.SimpleController.hello()
2014-04-26 22:54:42.376  INFO 7236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-04-26 22:54:42.377  INFO 7236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-04-26 22:54:42.447  INFO 7236 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2014-04-26 22:54:42.459  INFO 7236 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080/http
2014-04-26 22:54:42.460  INFO 7236 --- [           main] c.r.spring.boot.SimpleController         : Started SimpleController in 1.675 seconds (JVM running for 1.944)
2014-04-26 22:54:54.963  INFO 7236 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2014-04-26 22:54:54.963  INFO 7236 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2014-04-26 22:54:54.971  INFO 7236 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 8 ms

会产生上面的输出，查看日志可以发现默认使用的是tomcat，端口绑定在8080，现在让我们来访问：http://localhost:8080/hello

就可以看到我们代码中输出的字样：hello world了。

回首这个过程，是不是相比于以前快速了许多呢

参考资料：

1.　　Spring Boot Reference Guide