Spring Boot (#1 quick start)

時間 2019-11-18

標籤 spring boot quick start 欄目 Spring 简体版

原文原文鏈接

Spring Boot (#1 quick start)

官方文檔html

Spring Boot是爲了簡化Spring應用的建立、運行、調試、部署等而出現的，使用它能夠作到專一於Spring應用的開發，而無需過多關注XML的配置。java

簡單來講，它提供了一堆依賴打包，並已經按照使用習慣解決了依賴問題---習慣大於約定。git

Spring Boot默認使用tomcat做爲服務器，使用logback提供日誌記錄。github

Spring Boot提供了一系列的依賴包，因此須要構建工具的支持：maven 或 gradleweb

Spring Boot 預約義了一些應用啓動器：具體能夠見博客Spring Boot的啓動器Starter詳解spring

Featuresapache

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

以官網quick start 爲例（maven）：tomcat

新建一個maven項目

pom中parent設爲 spring-boot-starter-parent 。建議使用最新的 RELEASE 版本springboot

添加應用須要的starter模塊，做爲示例，咱們僅添加web starter應用啓動器。web starter應用啓動器包含了一系列依賴包組合，如spring-web,spring-webmvc,tomcat-embed-,jackson,spring-,spring-boot-autoconfigure。服務器

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,用於自動配置，它會根據你的pom配置（實際上應該是根據具體的依賴）來判斷這是一個什麼應用，並建立相應的環境
SpringApplication 啓動步驟

建立一個合適的ApplicationContext實例（取決於classpath）。
註冊一個CommandLinePropertySource，以便將命令行參數做爲Spring properties。
刷新application context，加載全部單例beans。
激活全部CommandLineRunner beans。

3 啓動訪問

直接運行main方法直接啓動

...... 一次完成的啓動見後面的分析
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)

直接訪問 localhost:8080 就能夠看到頁面輸出 hello world

配置

在classpath下的 application.properties 或者 application.yaml 文件中設置便可

好比更改端口號，變動項目路徑，例以下面的配置就須要 localhost:8080/springboot才能訪問

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

啓動步驟分析

[           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

啓動SampleController。
查找active profile，無，設爲default。
刷新上下文。
初始化tomcat，設置端口8080，設置訪問方式爲http。
啓動tomcat服務。
啓動Servlet引擎。
Spring內嵌的WebApplicationContext 初始化開始。
Spring內嵌的WebApplicationContext 初始化完成。
映射servlet，將 dispatcherServlet 映射到 [/] 。
映射filter，將 characterEncodingFilter 映射到 [/*] 。
映射filter，將 hiddenHttpMethodFilter 映射到 [/*] 。
映射filter，將 httpPutFormContentFilter 映射到 [/*] 。
映射filter，將 requestContextFilter 映射到 [/*] 。
第22行，查找 @ControllerAdvice。
第23行，映射路徑 "{[/]}" 到 cn.larry.spring.controller.SampleController.home()。
第24行，映射路徑 "{[/error]}" 到 org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)。
第25行，映射路徑 "{[/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啓動完畢。
SampleController啓動耗費的時間。
初始化 dispatcherServlet 。
dispatcherServlet 的初始化已啓動。
dispatcherServlet 的初始化已完成。
收到shutdown關閉請求。
關閉AnnotationConfigEmbeddedWebApplicationContext。