configuration file

There are two configuration file formats for SpringBoot. You can choose one of them. yaml is officially recommended:

• Format of application.properties key=value
• application.yaml key: value format

Profile location

SpringBoot loads the main configuration file from all four locations; complementary configuration. Priority is from high to low.

• --spring.config.location=F:/application.yaml
• /config/application.yaml
• /application.yaml
• /src/main/resources/config/application.yaml
• /src/main/resources/application.yaml

Features of yaml format

• There must be a space after the colon, which cannot be omitted
• Use indent to control hierarchy, and the left aligned ones are the same hierarchy
• Case sensitive properties and values
• Special characters in double quotation marks will escape output, such as "hello \n world" will break
• Special characters in double quotation marks will be output as they are, as seen in 'hello \n world'

Configuration example

# src/main/resources/application.properties
server.port=8081

# src/main/resources/application.yaml
server:
    port: 8081

# Object form
student:
    name: zhangsan
    age: 18

# In line object form
student: {name: zhangsan,age: 18}

# Array form
pets:
    - cat
    - dog
    - pig

# In row array form
pets: [cat,dog,pig]

Configure banner

# src/main/resources/banner.txt
# https://www.bootschool.net/ascii-art
        _ _                                     
      _(9(9)__        __/^\/^\__                
     /o o   \/_     __\_\_/\_/_/_               
     \___,   \/_   _\.'       './_      _/\_    
      `---`\  \/_ _\/           \/_   _|.'_/    
            \  \/_\/      /      \/_  |/ /      
             \  `-'      |        ';_:' /       
             /|          \      \     .'        
            /_/   |,___.-`',    /`'---`         
             /___/`       /____/                

Inject yaml configuration file (mode 1)

package com.wu.helloworld.pojo;

@Component
public class Dog {
    @Value("Huang")
    private String name;
    @Value("18")
    private Integer age;
}

@SpringBootTest
class HelloworldApplicationTests {
    @Autowired
    Dog dog;

    @Test
    public void contextLoads() {
        System.out.println(dog)
    }
}

Inject yaml configuration file (mode 2)

<!-- Import profile processor dependency, reboot required IDE -->
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-configuration-processor</artifactId>
  <optional>true</optional>
</dependency>

package com.wu.helloworld.pojo;

@Component
public class Dog {
    private String name;
    private Integer age;
    
    //Constructor, get, set, toString and other methods  
}

@Component
@ConfigurationProperties(prefix = "person")
public class Person {
    private String name;
    private Integer age;
    private Boolean happy;
    private Date birth;
    private Map<String,Object> maps;
    private List<Object> lists;
    private Dog dog;
    
    //Constructor, get, set, toString and other methods  
}

person:
  name: wu_${random.uuid}
  age: ${random.int}
  happy: false
  birth: 2000/01/01
  maps: {k1: v1,k2: v2}
  lists:
   - code
   - girl
   - music
  dog:
    name: ${person.dogName:Default name}_Prosperous wealth
    age: 1

@SpringBootTest
class DemoApplicationTests {
    @Autowired
    Person person;

    @Test
    public void contextLoads() {
        System.out.println(person);
    }
}

Inject properties profile

Set the encoding format of properties to UTF-8:

File / Settings / File Encodings / Properties Files / UTF-8 && √ Transparent native-to-ascii conversion

# src/main/resources/person.properties
person.name=wu
person.age=18
person.sex=male

@PropertySource(value = "classpath:person.properties")
@Component
public class Person {
    @Value("${person.name}") // Take value from configuration file
    private String name;
    @Value("#{9*2}")  // #{SPEL} Spring expression
    private int age;
    @Value("male")  // Literal
    private String sex;
}

Loose binding

dog:
    first-name: Prosperous wealth
    age: 3

@Component
public class Dog {
    private String firstName;  // The configuration value of the horizontal bar can be bound
    private Integer age;
}