springboot项目略述

1.springboot项目是由启动器、父项目启动器等组成

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.2.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

2.打开父项目启动器，其中配置了另一个父项目关键字dependencies:

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-dependencies</artifactId>
    <version>2.2.2.RELEASE</version>
    <relativePath>../../spring-boot-dependencies</relativePath>
  </parent>

3.打开2中父项目，在这个项目中配置了依赖jar包的版本号，类似版本仲裁中心：

<properties>
    <activemq.version>5.15.11</activemq.version>
    <antlr2.version>2.7.7</antlr2.version>
    <appengine-sdk.version>1.9.77</appengine-sdk.version>
    <artemis.version>2.10.1</artemis.version>
    <aspectj.version>1.9.5</aspectj.version>
    <assertj.version>3.13.2</assertj.version>
    <atomikos.version>4.0.6</atomikos.version>
    <awaitility.version>4.0.1</awaitility.version>
    <bitronix.version>2.1.4</bitronix.version>
    ....

4.打开>spring-boot-starter-web，可以看到web场景开发所需要的各种jar包及依赖组件：

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

<dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot</artifactId>
        <version>2.2.2.RELEASE</version>
      </dependency>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-test</artifactId>
        <version>2.2.2.RELEASE</version>
      </dependency>
      ...

5.springboot提供了各种场景启动器，以帮助我们快速开发项目的