SpringBoot-(1)配置文件的编写

SpringBoot配置文件类型和作用

SpringBoot是基于约定的，所以很多配置都有默认值，但如果想使用自己的配置替换默认配置的话，就可以使用application.properties或者application.yml（application.yaml）进行配置。
SpringBoot默认会从Resources目录下加载application.properties或application.yml（application.yaml）文件
其中，application.properties文件是键值对类型的文件，之前一直在使用，所以此处不在对properties文件的格式进行阐述。除了properties文件外，SpringBoot还可以使用yml文件进行配置。

application.yml配置文件

YML文件格式是YAML (YAML Aint Markup Language)编写的文件格式，YML文件的扩展名可以使用.yml或者.yaml。

1、配置普通数据： key: value 示例：

name: haohao

2、配置对象数据：

person:
  name: haohao
  age: 31
  addr: beijing

3、 配置Map数据：
同上面的对象写法
4、配置数组（List、Set）数据：

city:
  - beijing
  - tianjin
  - shanghai
  - chongqing
  
#或者

city: [beijing,tianjin,shanghai,chongqing]

#集合中的元素是对象形式
student:
  - name: zhangsan
    age: 18
    score: 100
  - name: lisi
    age: 28
    score: 88
  - name: wangwu
    age: 38
    score: 90

SpringBoot配置信息的查询

SpringBoot的配置文件，主要的目的就是对配置信息进行修改的，但在配置时的key从哪里去查询呢？我们可以查阅SpringBoot的官方文档。
文档URL：https://docs.spring.io/spring-boot/docs/2.0.1.RELEASE/reference/htmlsingle/#common-application-properties
常用的配置摘抄如下：

# QUARTZ SCHEDULER (QuartzProperties)
spring.quartz.jdbc.initialize-schema=embedded # Database schema initialization mode.
spring.quartz.jdbc.schema=classpath:org/quartz/impl/jdbcjobstore/tables_@@platform@@.sql # Path to the SQL file to use to initialize the database schema.
spring.quartz.job-store-type=memory # Quartz job store type.
spring.quartz.properties.*= # Additional Quartz Scheduler properties.

# ----------------------------------------
# WEB PROPERTIES
# ----------------------------------------

# EMBEDDED SERVER CONFIGURATION (ServerProperties)
server.port=8080 # Server HTTP port.
server.servlet.context-path= # Context path of the application.
server.servlet.path=/ # Path of the main dispatcher servlet.

# HTTP encoding (HttpEncodingProperties)
spring.http.encoding.charset=UTF-8 # Charset of HTTP requests and responses. Added to the "Content-Type" header if not set explicitly.

# JACKSON (JacksonProperties)
spring.jackson.date-format= # Date format string or a fully-qualified date format class name. For instance, `yyyy-MM-dd HH:mm:ss`.

# SPRING MVC (WebMvcProperties)
spring.mvc.servlet.load-on-startup=-1 # Load on startup priority of the dispatcher servlet.
spring.mvc.static-path-pattern=/** # Path pattern used for static resources.
spring.mvc.view.prefix= # Spring MVC view prefix.
spring.mvc.view.suffix= # Spring MVC view suffix.

# DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.driver-class-name= # Fully qualified name of the JDBC driver. Auto-detected based on the URL by default.
spring.datasource.password= # Login password of the database.
spring.datasource.url= # JDBC URL of the database.
spring.datasource.username= # Login username of the database.

# JEST (Elasticsearch HTTP client) (JestProperties)
spring.elasticsearch.jest.password= # Login password.
spring.elasticsearch.jest.proxy.host= # Proxy host the HTTP client should use.
spring.elasticsearch.jest.proxy.port= # Proxy port the HTTP client should use.
spring.elasticsearch.jest.read-timeout=3s # Read timeout.
spring.elasticsearch.jest.username= # Login username.