Introduction to yaml configuration in Spring Boot

One, yaml

Spring boot uses a global configuration file, which is fixed. It can be application.xml or application.yaml, placed in the /resources or /config directory

• yaml: is a markup language, data-centric, more suitable for configuration files than xml and json
• XML configuration example:

  <server>
       <port> 8081</port>
   </server>

• yml configuration example:

     server:
        port: 8085
        path: /hello

 

2.yaml writing

Reference syntax: https://bitbucket.org/asomov/snakeyaml/wiki/Documentation#markdown-header-yamlsyntax
Literal variables: single, indivisible value (number, string, boolean, date)

 

Object, Map (key:value key-value pair):

 

person:
     name: tom
     age: 18
personMap:
     username: herry
     age: 20

 

person:{name: tom,age: 18}

 

Array: List, Set

 

ainamals:
 - dog
 - cat
 - snack

 

animals:[dog,cat,snack]

 

Three, yaml test

1. Import the configuration file processor, there will be a prompt when writing the configuration

		<!-- 导入文件处理器，配置文件进行绑定的时候，就会有提示-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>

 

2.java bean

public class Dog {
 private String name;
 private Integer age;
 }
  /**
* 将配置文件中的每一个值，映射到这个组件中
*@ConfigurationProperties: 此注解表示告诉sprigboot将本类中的
*       所有属性和配置文件中相关配置进行一一绑定
*prefix = "person" :配置文件中的哪个进行绑定
*@Component: 只有是容器中的组件才会作用
*
*/
@Component
@ConfigurationProperties(prefix = "person")
public class Person {
 private String name;
 private Integer age;
 private Boolean boss;
 private Date birthday;

 private Map<String,Object> map;
 private List<Object> list;
 private Dog dog;
}

 

3. Configuration file injection

application.yml

person:
    name: tom
    age: 17
    boss: true
    birthday: 2018/01/12
    map:
      k1: v1
      k2: v2
    list:
      - cat
      - fish
      - dog
    dog:
      name: goodboy
      age: 3

 

application.properties

#配置properties属性
# idea properties默认是utf-8
person.name=tim
person.age=16
person.boss=false
person.birthday=2014/11/23
person.map.k1=v1
person.map.k2=22
person.list=cat,dog,fish
person.dog.name=goodboy
person.dog.age=3

 

4. Test the class, start it, and observe whether the console prints

/**
 * Spring boot 单元测试
 *
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootHelloworldQuickApplicationTests {

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

 

The default utf-8 properties configuration file in idea may be garbled

• Grammar reference and verification address: http://www.yaml.org/ https://nodeca.github.io/js-yaml/

• Two, yaml syntax specification

  1. Basic grammar of yaml

• Use indentation to indicate hierarchical relationships
• Tab key is not allowed when indenting, only spaces are allowed. Spaces to control the hierarchy
• k: ( space ) v: represents a pair of key-value pairs ( spaces must be present );
• The number of indented spaces is not important, as long as the elements of the same level are aligned to the left
• Case Sensitive
• k: v: write directly literally
• String:
  silently do not add single quotation marks or double quotation marks
  "": Double quotation marks do not escape special characters in the string, special characters will express their own meaning. For example, "Li" Li Si\n 20 years old" Output: Li Si wraps 20 years old
  '': Single quote; special characters will be escaped, and special characters are ultimately just ordinary string data. Such as "Li" Li Si\n 20 Years old" Output: Li Si\n 20 years old
  • File: Multiple files are separated by ---
• The object is key: value, separated by a colon
• Use a space after the colon to separate the key value
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• Inline writing:
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• - represents an element in the array
• Arrays and objects and combined use
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• Inline writing
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