1.配置文件格式（3种）

例：修改服务器端口。（3种）

src/main/resources/application.properties

server.port=80

src/main/resources/application.yml（主要用这种）

server:
  port: 80

src/main/resources/application.yaml

server:
  port: 80

SpringBoot配置文件加载优先级：/application.properties > application.yml > application.yaml

2.yaml数据格式

yaml，一种数据序列化格式。

优点：容易阅读、以数据为中心，重数据轻格式。

yam文件扩展名：.yml(主流)、.yaml

语法规则：
大小写敏感
属性值前面添加空格。（空格和冒号要隔开）
# 表示注释

数组格式：

enterprise:
  name: abc
  age: 16
  tel: 111111
  subject:
    - Java
    - C
    - C++

3.yaml数据读取方式（3种）

application.yml

lesson: SpringBoot

server:
  port: 80

enterprise:
  name: abc
  age: 16
  tel: 111111
  subject:
    - Java
    - C
    - C++

controller/BookController.java 有下面三种写法

① @Value（直接读取）

package com.example.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/books")
public class BookController {

    @Value("${lesson}")
    private String lesson;

    @Value("${server.port}")
    private Integer port;

    @Value("${enterprise.subject[0]}")
    private String subject_0;

    @GetMapping("/{id}")
    public String getById(@PathVariable Integer id) {
        System.out.println(lesson);
        System.out.println(port);
        System.out.println(subject_0);
        return "hello, spring boot!";
    }
}

② Environmet（封装后读取）

package com.example.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/books")
public class BookController {
    
    @Autowired
    private Environment environment;

    @GetMapping("/{id}")
    public String getById(@PathVariable Integer id) {
        System.out.println(environment.getProperty("lesson"));
        System.out.println(environment.getProperty("server.port"));
        System.out.println(environment.getProperty("enterprise.age"));
        System.out.println(environment.getProperty("enterprise.subject[1]"));
        return "hello, spring boot!";
    }
}

③ 实体类封装属性（封装后读取）

package com.example.controller;

import com.example.domain.Enterprise;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/books")
public class BookController {

    @Autowired
    private Enterprise enterprise;

    @GetMapping("/{id}")
    public String getById(@PathVariable Integer id) {
        System.out.println(enterprise);
        return "hello, spring boot!";
    }
}

需要额外封装一个类domain/enterprise.java

package com.example.domain;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.Arrays;

@Component
@ConfigurationProperties(prefix = "enterprise")
public class Enterprise {
    private String name;
    private Integer age;
    private String tel;
    private String[] subject;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    public void setSubject(String[] subject) {
        this.subject = subject;
    }

    @Override
    public String toString() {
        return "Enterprise{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", tel='" + tel + '\'' +
                ", subject=" + Arrays.toString(subject) +
                '}';
    }
}

pom.xml也需要额外添加一个依赖

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-configuration-processor</artifactId>
  <optional>true</optional>
</dependency>

4.多环境开发配置

resources/application.xml

spring:
  profiles:
    active: pro

---
# 开发
spring:
  config:
    activate:
      on-profile: dev
server:
  port: 80

---
# 生产
spring:
  config:
    activate:
      on-profile: pro
server:
  port: 81

---
# 测试
spring:
  config:
    activate:
      on-profile: test
server:
  port: 82

5.使用命令行启动多环境

java -jar xxx.jar --spring.profiles.active=test --server.port=88

参数加载的优先顺序可以从官网获得：Core Features

6.Maven与SpringBoot关联操作

在开发中，关于环境配置，应该以Maven为主，SpringBoot为辅。

①Maven中设置多环境属性

pom.xml

  <profiles>
		<profile>
			<id>dev</id>
			<properties>
				<profile.active>dev</profile.active>
			</properties>
		</profile>
		<profile>
			<id>pro</id>
			<properties>
				<profile.active>pro</profile.active>
			</properties>
			<activation>
				<activeByDefault>true</activeByDefault>
			</activation>
		</profile>
		<profile>
			<id>test</id>
			<properties>
				<profile.active>test</profile.active>
			</properties>
		</profile>
	</profiles>

使用插件对资源文件开启对默认占位符的解析

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-resources-plugin</artifactId>
  <version>3.3.1</version>
  <configuration>
    <encoding>UTF-8</encoding>
    <useDefaultDelimiters>true</useDefaultDelimiters>
  </configuration>
</plugin>

②SpringBoot引入Maven属性

application.yml

spring:
  profiles:
    active: ${profile.active}

---
# 开发
spring:
  config:
    activate:
      on-profile: dev
server:
  port: 80

---
# 生产
spring:
  config:
    activate:
      on-profile: pro
server:
  port: 81

---
# 测试
spring:
  config:
    activate:
      on-profile: test
server:
  port: 82

③Maven打包，进行测试