Spring Boot 學習 (1): 初始化工程

spring boot 專案初始化，介紹三種方式：IntelliJ 建立、Spring CLI 建立以及手動建立，工程使用 gradle 構建工具。

IntelliJ建立

1. 選擇 spring initializr

   

2. 填寫自己想要的配置資訊

   

3. 選擇依賴包：

   

4. 配置工程名和工程所在目錄：

   

   進入到工程，如下圖所示:

建立完成。

Spring CLI建立

示例：

spring init -dweb,data-jpa,h2,thymeleaf --build gradle initbycli
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執行命令後會顯示：

Using service at https://start.spring.io
Project extracted to '<current_path>/initbycli'
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執行完成會看到當前目錄下會多出 initbycli 目錄.

.
└── 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
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可以看到基本工程目錄檔案已經建立好了。

再看一下 Spring CLI 的說明：

$ 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
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說明：

• 依賴： 使用 -d, --dependencies <String>, , 號分割.
• 專案構建型別: --build <String>, 預設為 maven, 另一選項是 gradle.
• 初始化型別: --format <String>, 預設為 project, 會初始化整個工程的目錄結構。可選項是 build, 只會生成工程所需要的 build.gradle 檔案.
• 檢視有哪些可以配置的：--list, 命令輸出以後，內容包括可選的依賴包，工程型別和構建屬性（ java 版本等).

手動建立

1. 建立工程目錄: mkdir initbyself

2. 在工程目錄下建立 build.gradle 檔案，

   cd initbyself
   vim build.gradle
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   build.gradle 內容為：

   	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'
   	}
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3. 建立 setting.gradle 檔案

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

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4. 建立java程式碼目錄

   mkdir -p src/main/java/com/example/initbyself
   mkdir -p src/main/java/resources
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5. 建立 application

• 切換到程式碼目錄 cd src/main/java/com/example/initbyself
• 編寫原始碼檔案 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);
  	}
  
  }
  
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6. 執行 gradle build， 結果為:

   > 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
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7. 執行專案:

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)
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此時，已說明工程初始化成功了。

小結

以上是 Spring Boot 專案的初始化的三種方式，不一定全。第一種和第二種都依賴 https://start.spring.io 這個地址，這是官方提供的快速初始化方式，第三種是我們全手動一步一步初始化，需要對構建工具十分熟悉。