1. File Type

1.1、properties

properties file is a configuration file, mainly used to store configuration information, etc.

1.2、yaml

1.2.1. Introduction

YAML is a recursive acronym for "YAML Ain't Markup Language" (YAML is not a markup language). When this language was developed, YAML actually meant: "Yet Another Markup Language" (still a markup language).

Great for data-centric profiles

1.2.2. Basic syntax

key: space between value kv (space after colon)

Case Sensitive

Use indentation to indicate hierarchy
Indentation does not allow tabs, only spaces
The number of spaces indented does not matter, as long as elements at the same level are left-aligned
'#' means a comment
The string does not need to be quoted. If you want to add it, '' and "" indicate that the content of the string will be escaped/not escaped

1.2.3, data type

Literal: A single, indivisible value. date, boolean, string, number, null

String type can be represented by single or double quotes
# Single quotes will output \n as a string, double quotes will output \n as a newline
# Single quotes will not make the escape character effective, double quotation marks will make the escape character effective

k: v

Object: A collection of key-value pairs. map, hash, set, object

#行内写法：  
k: {k1:v1,k2:v2,k3:v3}
#或(注意缩进对齐 和 空格)
k: 
    k1: v1
    k2: v2
    k3: v3

Array: An ordered set of values. array, list, queue

#行内写法：(注意空格)
k: [v1,v2,v3]
#或者
k:
 - v1
 - v2
 - v3

1.2.4. Examples

① Introduce lombok dependencies and create two classes

@Component
@ConfigurationProperties(prefix = "person")
@Data
@ToString
public class Person {
    private String userName;
    private Boolean boss;
    private Date birth;
    private Integer age;
    private Pet pet;
    private String[] interests;
    private List<String> animal;
    private Map<String, Object> score;
    private Set<Double> salarys;
    private Map<String, List<Pet>> allPets;
}

@Data
@ToString
public class Pet {
    private String name;
    private Double weight;
}

② Create a yaml configuration file, application.yaml, the suffix can also be yml

person:
  userName: zhangsan
  boss: false
  birth: 2019/12/12 20:12:33
  age: 18
  pet:
    name: tomcat
    weight: 23.4
  interests: [ 篮球,游泳 ]
  animal:
    - jerry
    - mario
  score:
    english:
      first: 30
      second: 40
      third: 50
    math: [ 131,140,148 ]
    chinese: { first: 128,second: 136 }
  salarys: [ 3999,4999.98,5999.99 ]
  allPets:
    sick:
      - { name: tom }
      - { name: jerry,weight: 47 }
    health: [ { name: mario,weight: 47 } ]

2. Configuration Tips

Custom class and configuration file bindings are generally silent. And it will prompt that the SpringBoot configuration annotation processor is not configured

Just add dependencies

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

To avoid packaging annotation processors together

 <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.springframework.boot</groupId>
                            <artifactId>spring-boot-configuration-processor</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

SpringBoot - 4. Configuration file