Spring Boot (#1 quick start)

Spring Boot (#1 quick start)

官方文档

Spring Boot是为了简化Spring应用的创建、运行、调试、部署等而出现的,使用它可以做到专注于Spring应用的开发,而无需过多关注XML的配置。

简单来说,它提供了一堆依赖打包,并已经按照使用习惯解决了依赖问题---习惯大于约定。

Spring Boot默认使用tomcat作为服务器,使用logback提供日志记录。

Spring Boot提供了一系列的依赖包,所以需要构建工具的支持:maven 或 gradle

Spring Boot 预定义了一些应用启动器:具体可以见博客Spring Boot的启动器Starter详解

Features

  • Create stand-alone Spring applications
  • Embed Tomcat, Jetty or Undertow directly (no need to deploy WAR files)
  • Provide opinionated 'starter' POMs to simplify your Maven configuration
  • Automatically configure Spring whenever possible
  • Provide production-ready features such as metrics, health checks and externalized configuration
  • Absolutely no code generation and no requirement for XML configuration

quick start

以官网quick start 为例(maven):

新建一个maven项目

pom中parent设为 spring-boot-starter-parent 。建议使用最新的 RELEASE 版本

添加应用需要的starter模块,作为示例,我们仅添加web starter应用启动器。web starter应用启动器包含了一系列依赖包组合,如spring-web,spring-webmvc,tomcat-embed-,jackson,spring-,spring-boot-autoconfigure。

pom.xml

<?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>cn.ifengkou</groupId>
    <artifactId>spring-boot-test</artifactId>
    <version>1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
    </parent>

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

</project>

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;

/**
 * 描述
 *
 * @author shenlongguang<https://github.com/ifengkou>
 * @date 2017/4/11 17:43
 */
@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
        return "hello world";
    }

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

@EnableAutoConfiguration,用于自动配置,它会根据你的pom配置(实际上应该是根据具体的依赖)来判断这是一个什么应用,并创建相应的环境
SpringApplication 启动步骤

  1. 创建一个合适的ApplicationContext实例 (取决于classpath)。
  2. 注册一个CommandLinePropertySource,以便将命令行参数作为Spring properties。
  3. 刷新application context,加载所有单例beans。
  4. 激活所有CommandLineRunner beans。

3 启动 访问

直接运行main方法直接启动

...... 一次完成的启动见后面的分析
2017-04-11 18:46:54.255  INFO 4868 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-04-11 18:46:54.307  INFO 4868 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-04-11 18:46:54.311  INFO 4868 --- [           main] c.i.s.controller.SampleController        : Started SampleController in 2.585 seconds (JVM running for 3.044)

直接访问 localhost:8080 就可以看到页面输出 hello world

配置

在classpath下的 application.properties 或者 application.yaml 文件中设置即可

比如更改端口号,变更项目路径,例如下面的配置就需要 localhost:8080/springboot才能访问

application.yaml

# Server settings (ServerProperties)
server:
  port: 8080
  address: 127.0.0.1
  sessionTimeout: 30
  contextPath: /springboot

  # Tomcat specifics
  tomcat:
    accessLogEnabled: false
    protocolHeader: x-forwarded-proto
    remoteIpHeader: x-forwarded-for
    basedir:
    backgroundProcessorDelay: 30 # secs

application.properties
# Server settings (ServerProperties)
server.port=8080
server.address=127.0.0.1
#server.sessionTimeout=30
server.contextPath=/aaa

# Tomcat specifics
#server.tomcat.accessLogEnabled=false
server.tomcat.protocolHeader=x-forwarded-proto
server.tomcat.remoteIpHeader=x-forwarded-for
server.tomcat.basedir=
server.tomcat.backgroundProcessorDelay=30

启动步骤分析

[           main] c.i.s.controller.SampleController        : Starting SampleController on SC-201603222017 with PID 4868 (E:\workspace\spring-boot-test\target\classes started by Administrator in E:\workspace\spring-boot-test)
[           main] c.i.s.controller.SampleController        : No active profile set, falling back to default profiles: default
[           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6d5620ce: startup date [Tue Apr 11 18:46:52 CST 2017]; root of context hierarchy
[           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
[           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
[           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.11
[ost-startStop-1] o.a.c.c.C.[.[localhost].[/springboot]    : Initializing Spring embedded WebApplicationContext
[ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1377 ms
[ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
[ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
[ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
[ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
[ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
[           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6d5620ce: startup date [Tue Apr 11 18:46:52 CST 2017]; root of context hierarchy
[           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto java.lang.String cn.ifengkou.springboot.controller.SampleController.home()
[           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)
[           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)
[           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
[           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
[           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
[           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
[           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
[           main] c.i.s.controller.SampleController        : Started SampleController in 2.585 seconds (JVM running for 3.044)
[0.1-8080-exec-3] o.a.c.c.C.[.[localhost].[/springboot]    : Initializing Spring FrameworkServlet 'dispatcherServlet'
[0.1-8080-exec-3] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
[0.1-8080-exec-3] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 13 ms
  • 启动SampleController。
  • 查找active profile,无,设为default。
  • 刷新上下文。
  • 初始化tomcat,设置端口8080,设置访问方式为http。
  • 启动tomcat服务。
  • 启动Servlet引擎。
  • Spring内嵌的WebApplicationContext 初始化开始。
  • Spring内嵌的WebApplicationContext 初始化完成。
  • 映射servlet,将 dispatcherServlet 映射到 [/] 。
  • 映射filter,将 characterEncodingFilter 映射到 [/*] 。
  • 映射filter,将 hiddenHttpMethodFilter 映射到 [/*] 。
  • 映射filter,将 httpPutFormContentFilter 映射到 [/*] 。
  • 映射filter,将 requestContextFilter 映射到 [/*] 。
  • 第22行,查找 @ControllerAdvice。
  • 第23行,映射路径 "{[/]}" 到 cn.larry.spring.controller.SampleController.home()。
  • 第24行,映射路径 "{[/error]}" 到 org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)。
  • 第25行,映射路径 "{[/error],produces=[text/html]}" 到 org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)。
  • tomcat启动完毕。
  • SampleController启动耗费的时间。
  • 初始化 dispatcherServlet 。
  • dispatcherServlet 的初始化已启动。
  • dispatcherServlet 的初始化已完成。
  • 收到shutdown关闭请求。
  • 关闭AnnotationConfigEmbeddedWebApplicationContext。
posted @ 2017-04-11 19:01  sloong  阅读(...)  评论(...编辑  收藏