Spring Boot从零入门3_创建Hello World及项目剖析

<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>com.xiaobaiai.examples</groupId>
	<artifactId>test_01_helloworld</artifactId>
	<version>0.0.1-SNAPSHOT</version>

    <!-- 下面为添加的依赖内容，spring-boot-starter-web -->
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.0.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<properties>
		<java.version>11</java.version>
	</properties>

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

package com.xiaobaiai;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@SpringBootApplication
@Controller
public class Test01HelloworldApplication {
	@RequestMapping("/")
    @ResponseBody
    public String index() {
        return "Hello World!";
    }

    public static void main(String[] args) {
        SpringApplication.run(Test01HelloworldApplication.class, args);
    }
}

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.0.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.xiaobaiai</groupId>
	<artifactId>test_02_helloworld</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>test_02_helloworld</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>11</java.version>
	</properties>

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

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

package com.xiaobaiai;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@SpringBootApplication
@Controller
public class Test02HelloworldApplication {
	@RequestMapping("/")
    @ResponseBody
    public String index() {
        return "Hello World!";
    }
	public static void main(String[] args) {
		SpringApplication.run(Test02HelloworldApplication.class, args);
	}
}

# 查看spring cli版本
$ spring --version
Spring CLI v2.2.0.RELEASE
# 查看spring所有帮助
$ spring --help
# 查看spring run命令帮助
$ spring help run
# 查看spring init命令帮助
$ spring help init
# 查看所有支持的dependencies，支持的工程类型(Project types，默认工程类型为marven-project)
$ spring init --list

$ spring init --list
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
:: Service capabilities ::  https://start.spring.io

Supported dependencies
+--------------------------------------+--------------------------------------------------------------+-------------------------------+
| Id                                   | Description                                                  | Required version              |
+--------------------------------------+--------------------------------------------------------------+-------------------------------+
......
| activemq                             | Spring JMS support with Apache ActiveMQ 'Classic'.           |                               |
| web                                  | Build web, including RESTful, applications using Spring MVC. |                               |
|                                      | Uses Apache Tomcat as the default embedded container.        |                               |
......
+--------------------------------------+--------------------------------------------------------------+-------------------------------+

Project types (* denotes the default)
+-----------------+------------------------------------------+-----------------------------+
| Id              | Description                              | Tags                        |
+-----------------+------------------------------------------+-----------------------------+
| gradle-build    | Generate a Gradle build file.            | build:gradle,format:build   |
| gradle-project  | Generate a Gradle based project archive. | build:gradle,format:project |
| maven-build     | Generate a Maven pom.xml.                | build:maven,format:build    |
| maven-project * | Generate a Maven based project archive.  | build:maven,format:project  |
+-----------------+------------------------------------------+-----------------------------+

Parameters
+-------------+------------------------------------------+------------------------------+
| Id          | Description                              | Default value                |
+-------------+------------------------------------------+------------------------------+
| artifactId  | project coordinates (infer archive name) | demo                         |
| bootVersion | spring boot version                      | 2.2.0.RELEASE                |
| description | project description                      | Demo project for Spring Boot |
| groupId     | project coordinates                      | com.example                  |
| javaVersion | language level                           | 1.8                          |
| language    | programming language                     | java                         |
| name        | project name (infer application name)    | demo                         |
| packageName | root package                             | com.example.demo             |
| packaging   | project packaging                        | jar                          |
| type        | project type                             | maven-project                |
| version     | project version                          | 0.0.1-SNAPSHOT               |
+-------------+------------------------------------------+------------------------------+

# 创建项目name: test_03_helloworld
# groupId: com.xiaobaiai
# artifactId: test_03_helloworld
# language: java/groovy/kotlin
# boot-version: 2.2.0
# 构建工具类型: marven-project/marven-build/gradle-project/gradle-build
# 依赖项(dependencies)：web
# java-version: java(jdk)版本
# --package-name: 包名
# --packaging:打包方式jar/war
# --extract: 不加这个参数则创建出来的项目就是已经压缩过的，跟用Spring Initializr Website创建出来的一样
# 最后一个test_03_helloworld即指定目标生成目录
$ mkdir test_03_helloworld
$ cd test_03_helloworld
$ spring init -n test_03_helloworld -g com.xiaobaiai -a test_03_helloworld -l java -b 2.2.0.RELEASE -t maven-project -d web --extract -j 11 --package-name com.xiaobaiai --extract test_03_helloworld

.
├── HELP.md
├── list
│   ├── HELP.md
│   ├── mvnw
│   ├── mvnw.cmd
│   ├── pom.xml
│   └── src
│       ├── main
│       └── test
├── mvnw
├── mvnw.cmd
├── pom.xml
└── src
    ├── main
    │   ├── java
    │   └── resources
    └── test
        └── java

# spring-boot:run为Spring Boot Maven Plugin插件所支持，还有如spring-boot:repackage/spring-boot:start/spring-boot:stop/spring-boot:build-info。
$ mvn spring-boot:run

<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>2.2.0.RELEASE</version>
	<relativePath /> <!-- lookup parent from repository -->
</parent>

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

<dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot</artifactId>
        <version>2.2.0.RELEASE</version>
      </dependency>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-test</artifactId>
        <version>2.2.0.RELEASE</version>
      </dependency>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-test-autoconfigure</artifactId>
        <version>2.2.0.RELEASE</version>
      </dependency>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-actuator</artifactId>
        <version>2.2.0.RELEASE</version>
      </dependency>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-actuator-autoconfigure</artifactId>
        <version>2.2.0.RELEASE</version>
        
        ......
        
    </dependencies>
</dependencyManagement>

<properties>
    ......
    <tomcat.version>9.0.27</tomcat.version>
    ......
</properties>

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
		</plugin>
	</plugins>
</build>

@SpringBootApplication
@Controller
public class Test02HelloworldApplication {
	@RequestMapping("/")
    @ResponseBody
    public String index() {
        return "Hello World!";
    }
	public static void main(String[] args) {
		SpringApplication.run(Test02HelloworldApplication.class, args);
	}

}

@Target(ElementType.TYPE) // 元注解，指定了注解运用的地方，注解就被限定了运用的场景，此处限定为可以给一个类型进行注解，比如类、接口、枚举
@Retention(RetentionPolicy.RUNTIME)  // 元注解， 注解可以保留到程序运行的时候，它会被加载进入到 JVM 中，所以在程序运行时可以获取到它们
@Documented // 元注解，将注解中的元素包含到 Javadoc 中去
@Inherited // 元注解，超类被 @Inherited 注解过的注解进行注解的话，那么如果它的子类没有被任何注解应用的话，那么这个子类就继承了超类的注解。
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
		@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
@ConfigurationPropertiesScan
public @interface SpringBootApplication {
    ......
}

@Controller
@RequestMapping("/appointments")
public class AppointmentsController {

    private final AppointmentBook appointmentBook;

    @Autowired
    public AppointmentsController(AppointmentBook appointmentBook) {
        this.appointmentBook = appointmentBook;
    }

    @RequestMapping(method = RequestMethod.GET)
    public Map<String, Appointment> get() {
        return appointmentBook.getAppointmentsForToday();
    }

    @RequestMapping(value="/{day}", method = RequestMethod.GET)
    public Map<String, Appointment> getForDay(@PathVariable @DateTimeFormat(iso=ISO.DATE) Date day, Model model) {
        return appointmentBook.getAppointmentsForDay(day);
    }

    @RequestMapping(value="/new", method = RequestMethod.GET)
    public AppointmentForm getNewForm() {
        return new AppointmentForm();
    }

    @RequestMapping(method = RequestMethod.POST)
    public String add(@Valid AppointmentForm appointment, BindingResult result) {
        if (result.hasErrors()) {
            return "appointments/new";
        }
        appointmentBook.addAppointment(appointment);
        return "redirect:/appointments";
    }
}

SpringApplication springApplication = new SpringApplication(SpringbootActionApplication.class);
// 关闭应用启动时的Banner，如下：
//  .   ____          _            __ _ _
// /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
//( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
// \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
//  '  |____| .__|_| |_|_| |_\__, | / / / /
// =========|_|==============|___/=/_/_/_/
// :: Spring Boot ::        (v2.2.0.RELEASE)
springApplication.setBannerMode(Banner.Mode.OFF);
springApplication.run(args);

# 关闭Banner
spring.main.banner-mode=off
# 修改WEB端口8080为8081
server.port = 8081
# 修改日志级别和中控台日志保存文件路径
# 所有文件日志打印级别为WARN
logging.level.root=WARN
# 指定包或具体类打印日志级别， 如logging.level.com.xiaobaiai=DEBUG
logging.level.{some.package.path}=DEBUG
# 默认日志都会打印到控制台，你可以设定打印到文件，即直接指定路径和文件名
logging.file=\path_to\logfile.log
# 也可以只指定路径，默认为spring.log
logging.file.path=C:\\Work\\sts4\\test_02_helloworld\\logs
# 自定义属性值，然后在应用程序中通过@Value注解来赋值，
# @Value(value=”${com.xiaobaiai.name}”)
# private String name;
com.xiaobaiai.name="小白AI"