Spring Boot 学习 (1): 初始化工程

spring boot 项目初始化，介绍三种方式：IntelliJ 创建、Spring CLI 创建以及手动创建，工程使用 gradle 构建工具。

IntelliJ创建

1. 选择 spring initializr
   
2. 填写自己想要的配置信息
   
3. 选择依赖包：
   
4. 配置工程名和工程所在目录：
   

进入到工程，如下图所示:

创建完成。

Spring CLI创建

示例：

spring init -dweb,data-jpa,h2,thymeleaf --build gradle initbycli

运行命令后会显示：

Using service at https://start.spring.io
Project extracted to '<current_path>/initbycli'

执行完成会看到当前目录下会多出 initbycli 目录.

.
└── initbycli
    ├── HELP.md
    ├── build.gradle
    ├── gradle
    │   └── wrapper
    │       ├── gradle-wrapper.jar
    │       └── gradle-wrapper.properties
    ├── gradlew
    ├── gradlew.bat
    ├── settings.gradle
    └── src
        ├── main
        │   ├── java
        │   │   └── com
        │   │       └── example
        │   │           └── initbycli
        │   │               └── DemoApplication.java
        │   └── resources
        │       ├── application.properties
        │       ├── static
        │       └── templates
        └── test
            └── java
                └── com
                    └── example
                        └── initbycli
                            └── DemoApplicationTests.java

可以看到基本工程目录文件已经创建好了。

再看一下 Spring CLI 的说明：

$ spring help init
spring init - Initialize a new project using Spring Initializr (start.spring.io)

usage: spring init [options] [location]

Option                       Description
------                       -----------
-a, --artifactId <String>    Project coordinates; infer archive name (for
                               example 'test')
-b, --boot-version <String>  Spring Boot version (for example '1.2.0.RELEASE')
--build <String>             Build system to use (for example 'maven' or
                               'gradle') (default: maven)
-d, --dependencies <String>  Comma-separated list of dependency identifiers to
                               include in the generated project
--description <String>       Project description
-f, --force                  Force overwrite of existing files
--format <String>            Format of the generated content (for example
                               'build' for a build file, 'project' for a
                               project archive) (default: project)
-g, --groupId <String>       Project coordinates (for example 'org.test')
-j, --java-version <String>  Language level (for example '1.8')
-l, --language <String>      Programming language  (for example 'java')
--list                       List the capabilities of the service. Use it to
                               discover the dependencies and the types that are
                               available
-n, --name <String>          Project name; infer application name
-p, --packaging <String>     Project packaging (for example 'jar')
--package-name <String>      Package name
-t, --type <String>          Project type. Not normally needed if you use --
                               build and/or --format. Check the capabilities of
                               the service (--list) for more details
--target <String>            URL of the service to use (default: https://start.
                               spring.io)
-v, --version <String>       Project version (for example '0.0.1-SNAPSHOT')
-x, --extract                Extract the project archive. Inferred if a
                               location is specified without an extension

说明：

• 依赖： 使用 -d, --dependencies <String>, , 号分割.
• 项目构建类型: --build <String>, 默认为 maven, 另一选项是 gradle.
• 初始化类型: --format <String>, 默认为 project, 会初始化整个工程的目录结构。可选项是 build, 只会生成工程所需要的 build.gradle 文件.
• 查看有哪些可以配置的：--list, 命令输出以后，内容包括可选的依赖包，工程类型和构建属性（ java 版本等).

手动创建

1. 建立工程目录: mkdir initbyself

2. 在工程目录下建立 build.gradle 文件，

   cd initbyself
   vim build.gradle

   build.gradle 内容为：

       plugins {
           id 'org.springframework.boot' version '2.1.3.RELEASE'
           id 'java'
       }
       
       apply plugin: 'io.spring.dependency-management'
       
       group = 'com.example'
       version = '0.0.1-SNAPSHOT'
       sourceCompatibility = '1.8'
       
       repositories {
           mavenCentral()
       }
       
       dependencies {
           implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
           implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
           implementation 'org.springframework.boot:spring-boot-starter-web'
           runtimeOnly 'com.h2database:h2'
           testImplementation 'org.springframework.boot:spring-boot-starter-test'
       }

3. 创建 setting.gradle 文件

    pluginManagement {
        repositories {
            gradlePluginPortal()
        }
    }
    rootProject.name = 'initbyself'

1. 创建java代码目录

   mkdir -p src/main/java/com/example/initbyself
   mkdir -p src/main/java/resources

2. 创建 application

   • 切换到代码目录
     cd src/main/java/com/example/initbyself

   • 编写源码文件 DemoApplication.java

     package com.example.initbyself;
     
     import org.springframework.boot.SpringApplication;
     import org.springframework.boot.autoconfigure.SpringBootApplication;
     
     @SpringBootApplication
     public class DemoApplication {
     
         public static void main(String[] args) {
             SpringApplication.run(DemoApplication.class, args);
         }
     
     }
     

3. 运行 gradle build， 结果为:

   > Task :build
   Skipping task ':build' as it has no actions.
   :build (Thread[Daemon worker Thread 2,5,main]) completed. Took 0.0 secs.
   
   BUILD SUCCESSFUL in 3s
   2 actionable tasks: 2 executed

4. 运行项目:

java -jar build/libs/initbyself-0.0.1-SNAPSHOT.jar

 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.3.RELEASE)
.
.
.
.
.
2019-03-07 00:17:36.996  INFO 11848 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-03-07 00:17:36.999  INFO 11848 --- [           main] com.example.initbyself.DemoApplication   : Started DemoApplication in 19.497 seconds (JVM running for 19.992)

此时，已说明工程初始化成功了。

小结

以上是 Spring Boot 项目的初始化的三种方式，不一定全。第一种和第二种都依赖 https://start.spring.io 这个地址，这是官方提供的快速初始化方式，第三种是我们全手动一步一步初始化，需要对构建工具十分熟悉。