YAML语法入门

1、基本格式

• 用缩进表示层级，左对齐的数据属于同一层级；
• K:(空格)v 表示一个键值对
• 大小写敏感
• "#"表示注释

server:
  port: 8081

spring:
#这是注释
  datasource:
    url: jdbc:oracle:thin:@localhost:1521:orcl
    driver-class-name: oracle.jdbc.driver.OracleDriver
    username: ABC
    password: ABC

2、数据类型

yml支持以下数据类型

• 对象：键值对的集合，包括：map、字典
• 数组：一组按次序排列的值，包括：list和set
• 纯量（scalars）：即字面量，单个的、不可再分的值。包括：数字，字符串，布尔

3、设置方式

3.1、纯量

属性设置：

property:
  #字符串一般情况下不需要使用引号
  str0: 字符串
  #使用双引号时
  str1: "特殊转移字符\n被双引\t号包含时"
  #使用单引号时
  str2: '特殊转移字符\n被单引\t号包\r含时'
  num: 3.25 #数字
  bool: true #布尔值
  date: 2021/03/03 #日期
  time: 2021/03/03 17:12:35 # 时间
  birth: 2021-03-03 17:12:35

实体类：

@Component
@ConfigurationProperties(prefix = "property")
public class PropertyObject {
    private String str0;
    private String str1;
    private String str2;
    private String str3;
    private BigDecimal num;
    private boolean bool;
    private Date date;
    private Date time;

    @JsonFormat(timezone = "GMT+8",pattern="yyyy-MM-dd HH:mm:ss")
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
    private LocalDateTime birth;
}

输出：

{"str0":"字符串","str1":"特殊转移字符\n被双引\t号包含时","str2":"特殊转移字符\\n被单引\\t号包\\r含时","str3":null,"num":3.25,"bool":true,"date":"2021-03-02T16:00:00.000+00:00","time":"2021-03-03T09:12:35.000+00:00","birth":"2021-03-03 17:12:35"}

3.2、数组、list、set

属性设置：

property:
    #数组 多行写法，以 “- 值” 表示一个元素
    ints:
      - 1
      - 2
      - 3
      - 4
    # 数组，单行写法，与正常初始化一个数组一样
    strings: [abc,err,ok]
    list: [123,654,3.25,euuu]
    set:
      - abc
      - yue
      - ok

实体类：

@Component
@ConfigurationProperties(prefix = "property")
public class PropertyObject {
    private int[] ints;
    private String[] strings;
    private List list;
    private Set set;
}

输出：

{"ints":[1,2,3,4],"strings":["abc","err","ok"],"list":[123,654,3.25,"euuu"],"set":["abc","yue","ok"]}

3.3、对象、map

属性设置：

property:
  #单行写法
  map: {abc: abc,sks: 123}
  #多行写法
  person:
    name: 张三
    age: 25
  people:
    - {name: lisi,age: 13}
    - {name: 金士顿,age: 24}

实体类：

@Component
@ConfigurationProperties(prefix = "property")
public class PropertyObject {
    private Map map;
    private Person person;
    private List<Person> people;
}

输出：

{"map":{"abc":"abc","sks":123},"person":{"name":"张三","age":25},"people":[{"name":"lisi","age":13},{"name":"金士顿","age":24}]}

3.4、锚点与引用

yml可以通过 & 锚点和 ***** 别名，实现值引用

& 用来建立锚点（defaults），<< 表示合并到当前数据， * 用来引用锚点。

属性设置：

property:
  person: &zhangsan
    name: 张三
    age: 25
  person2: &p2
    <<: *zhangsan
  people:
    - {name: lisi,age: 13}
    - {name: 金士顿,age: 24}
    - <<: *zhangsan
    - <<: *p2

实体类：

@Component
@ConfigurationProperties(prefix = "property")
public class PropertyObject {
    private Person person;
    private Person person2;
    private List<Person> people;
}

输出：

{"person":{"name":"张三","age":25,"list":null},"person2":{"name":"张三","age":25,"list":null},"people":[{"name":"lisi","age":13,"list":null},{"name":"金士顿","age":24,"list":null},{"name":"张三","age":25,"list":null},{"name":"张三","age":25,"list":null}]}