一只胡说八道的猴子

多个yml配置文件：

在spring boot中是被允许的。这些配置文件的名称必须为application-***.yml，并且这些配置文件必须要在application.yml配置文件中激活之后才可以使用。
**
案例
**
比如有两个配置文件application-abc.yml，application-def.yml

These configuration files must be named as application-***.yml, and they must be activated in the application.yml configuration file before they can be used.
br> case
br> such as two configuration-abc.yml, application-def.yml

如果properties和yml配置文件同时存在在spring boot项目中：

那么这两类配置文件都有效。在两个配置文件中如果存在同名的配置项的话会以properties文件的为主。

Both profiles are valid. If there is a configuration with the same name in both profiles, the profile is dominated by the profile.

yml配置普通数据

语法： key: value

Syntax: Key: value

配置对象数据||配置Map数据

语法：
key:
key1: value1
key2: value2
** 或者：**
key: {key1: value1,key2: value2}

syntax: Key:
Key1: value1
key2: value2
** Or: br> key: {key1: value1, Key2: value2}

示例代码

example code

配置数组（List、Set）数据

语法：
key:

Syntax:
key:

• value1
• value2
  或者：
  key: [value1,value2]

注意：value1与之间的 - 之间存在一个空格
例子：

notes that there is an example of a space between
:

summary:

Spring Boot内部对大量的第三方库或Spring内部库进行了默认配置，这些配置是否生效，取决于我们是否引入了对应库所需的依赖，如果有那么默认配置就会生效。所以，我们使用SpringBoot构建一个项目，只需要引入所需框架的依赖，配置就可以交给SpringBoot处理了。除非你不希望使用SpringBoot的默认配置，它也提供了自定义配置的入口。

The default configuration within Spring Boot of a large number of third-party libraries or Spring internal libraries is valid, depending on whether we have introduced the required reliance on the corresponding library, and if so, the default configuration. So, we use SpringBoot to build a project by introducing the required framework, and the configuration is left to SpringBoot. Unless you do not want to use SpringBoot's default configuration, it also provides a custom configuration entry.

@ComponentScan

我们跟进源码：

We follow the source code :

并没有看到什么特殊的地方。我们查看注释：

doesn't see anything special. Let's look at the note:

大概的意思：
配置组件扫描的指令。提供了类似与 context:component-scan 标签的作用
通过basePackageClasses或者basePackages属性来指定要扫描的包。如果没有指定这些属性，那么将从声明这个注解的类所在的包开始，扫描包及子包
而我们的@SpringBootApplication注解声明的类就是main函数所在的启动类，因此扫描的包是该类所在包及其子包。因此，一般启动类会放在一个比较前的包目录中

approximation: command for the configuration component scan. Provides a function similar to that of confext:compont-scan tag
, which specifies the package to be scanned through the basePackageClasses or basePackages properties. If these properties are not specified, the scan package and the sub-pack will start with the package that states the type to be specified, and our @SpringBootApplication comment class is the start-up class of the main function, so the scanned package is the type of bag and its sub-packs.

processor adapter (HandlerAdapter):

我们看到，这里通过@EnableAutoConfiguration注解引入了两个属性：WebMvcProperties和ResourceProperties。这不正是SpringBoot的属性注入玩法嘛。
我们查看这两个属性类：

We see that two attributes have been introduced here through a note from @EnableAutoConfiguration: WebMvProperties and ResourcesProperties. It's not exactly SpringBoot's properties that are injected into the game.
We look at these two properties:

**如果我们要覆盖这些默认属性，只需要在application.properties中定义与其前缀prefix和字段名一致的属性即可。 **

** If we want to overwrite these default properties, we just need to define properties in application.properties that match their prefix prefix prefix and field name.**

SpringBoot为我们提供了默认配置，而默认配置生效的步骤：

1.@EnableAutoConfiguration注解会去寻找 META-INF/spring.factories 文件，读取其中以EnableAutoConfiguration 为key的所有类的名称，这些类就是提前写好的自动配置类

1. @EnableAutoConfiguration notes will look for META-INF/spring.factories to read the names of all classes of which EnableAutoConfiguration is the type of automatic configuration written in advance.

2.这些类都声明了 @Configuration 注解，并且通过 @Bean 注解提前配置了我们所需要的一切实例

2. All these classes have stated @Configuration and pre-configuring all the examples we need by @Bean

3.但是，这些配置不一定生效，因为有 @ConditionalOn 注解，满足一定条件才会生效。比如条件之一： 是一些相关的类要存在

3. However, these configurations do not necessarily take effect because there are @ConditionalOn notes that satisfy certain conditions for validity. For example, one condition is that some related categories exist.

4.类要存在，我们只需要引入了相关依赖（启动器），依赖有了条件成立，自动配置生效。
5.如果我们自己配置了相关Bean，那么会覆盖默认的自动配置的Bean

For the class to exist, we just need to introduce the relevant dependency (starter), which is created and automatically configured.
5. If we configure the relevant Bean ourselves, the default automatic configuration of Bean will be covered.

6.我们还可以通过配置application.yml文件，来覆盖自动配置中的属性

6. We can also overwrite properties in autoconfiguration by configuring application.yml files

1）启动器

所以，我们如果不想配置，只需要引入依赖即可，而依赖版本我们也不用操心，因为只要引入了SpringBoot提供的stater（启动器），就会自动管理依赖及版本了。
因此，玩SpringBoot的第一件事情，就是找启动器，SpringBoot提供了大量的默认启动器

So if we don't want to configure it, we just need to introduce dependence, and we don't have to worry about relying on the version, because as long as we have introduced the stateer (starter) provided by SpringBoot, we automatically manage the dependency and the version.
So the first thing to play SpringBoot is to find a starter, and SpringBoot provides a lot of default triggers.

2）全局配置

另外，SpringBoot的默认配置，都会读取默认属性，而这些属性可以通过自定义 application.properties 文件来
进行覆盖。这样虽然使用的还是默认配置，但是配置中的值改成了我们自定义的。
因此，玩SpringBoot的第二件事情，就是通过 application.properties 来覆盖默认属性值，形成自定义配置。我
们需要知道SpringBoot的默认属性key，非常多，可以再idea中自动提示

Furthermore, the default configuration of SpringBoot will read the default properties, which can be covered by custom application.properties files
. This is how the default configuration is used, but the value in the configuration has been changed to our custom.
So the second thing to play SpringBoot is to overwrite the default attribute values through application.properties to create a custom configuration. I
need to know the default properties of SpringBoot, which is a lot, which can be automatically hinted in the idea.

属性文件支持两种格式，application.properties和application.yml
yml的语法实例：

The attribute files support two formats, examples of syntaxes for application.properties and application.yml
yml:

如果properties和yml文件都存在，如果有重叠属性，默认以Properties优先。遇到需要修改的组件的配置项流程为：

If both the properties and yml files exist, if there are overlapping properties, the default priority is the Properties. The configuration process for components that need to be modified is as follows:

Lombok是一个可以通过简单的注解形式来帮助我们简化消除一些必须有但显得很臃肿的Java代码的工具，通过使用对应的注解，可以在编译源码的时候生成对应的方法

Lombok is a tool that can help us simplify the elimination of some of Java's code that must be swollen but that can be generated when compiling the source code by using the corresponding note.

步骤1

File->setting->Plugins ,然后搜索lombok

File-> setting-> Plugins, then search for Lombok
步骤二

在pom.xml文件中导入相关的依赖

Import Related Dependence in Pom.xml File

@Getter and @Setter

你可以用@Getter / @Setter注释任何字段（当然也可以注释到类上的），让lombok自动生成默认的getter / setter方法。
默认生成的方法是public的，如果要修改方法修饰符可以设置AccessLevel的值，例如：@Getter(access=AccessLevel.PROTECTED)
**

You can use @Getter/ @Setter to comment on any field (and, of course, to the class) to allow Lombok to automatically generate the default geter/ setter method.
The default generation method is public. If you want to modify the modifier method, you can set AccessLive @Getter(access=AccessLive. PROTECTED)
**

、

,

@ToString

生成toString()方法，默认情况下，它会按顺序（以逗号分隔）打印你的类名称以及每个字段。可以这样设置不包含哪些字段@ToString(exclude="id") / @ToString(exclude=)
如果继承的有父类的话，可以设置callSuper 让其调用父类的toString()方法，例如：@ToString(callSuper=true)

Generates tostring() method, which, by default, will print your class name in sequence (separated by commas) as well as each field. This can be done by setting out the fields that do not contain @Tostring(exclude=id) /strung> @Tostring (exclude=) >, if the successor has a parent, setting calll Super, for example: @Tostring(callSuper=true> >.

生成toString方法如下：

Tostring is generated by:

@EqualsAndHashCode

生成hashCode()和equals()方法，默认情况下，它将使用所有非静态，非transient字段。但可以通过在可选的exclude参数中来排除更多字段。或者，通过在parameter参数中命名它们来准确指定希望使用哪些字段。

Generates the HashCode() and equals() methods, which, by default, will use all non-static, non-transient fields. However, more fields can be excluded by using optional exclude parameters. Or, by naming them in parameter parameters, specify precisely which fields you want to use.

对比代码如下：

The comparison code is as follows:

• @NoArgsConstructor, @RequiredArgsConstructor, @AllArgsConstructor

@NoArgsConstructor生成一个无参构造方法。当类中有final字段没有被初始化时，编译器会报错，此时可用@NoArgsConstructor(force=true)，然后就会为没有初始化的final字段设置默认值 0 / false / null。对于具有约束的字段（例如@NonNull字段），不会生成检查或分配，因此请注意，正确初始化这些字段之前，这些约束无效。

@NoArgsConstructor generates a non-descriptive construction method. When there is a binal field in the class that is not initialized, the compiler is wrong. It can be used at @NoArgsConstructor(force=true), and then the default value 0/ false/ null is set for the non-informed final field. For bound fields (e.g. @NonNull field), the check or allocation is not generated, so note that these restrictions are invalid before the correct initialization of the field.

@RequiredArgsConstructor会生成构造方法（可能带参数也可能不带参数），如果带参数，这参数只能是以final修饰的未经初始化的字段，或者是以@NonNull注解的未经初始化的字段
@RequiredArgsConstructor(staticName="of")会生成一个of()的静态方法，并把构造方法设置为私有的

@RequiredArgsConstructor will generate a construction method (possibly with or without parameters) which, if accompanied by parameters, can only be based on an uninitialized field modified by the vinal, or
with an uninitial field @NonNull annotated by @RequiredArgsConstructor (staticName = "of") will generate a static method of lf() and set the construction method to private.

@AllArgsConstructor 生成一个全参数的构造方法

@Data

@Data 包含了 @ToString、@EqualsAndHashCode、@Getter / @Setter和@RequiredArgsConstructor的功能

@Data contains @ToString, @EqualsAndHashCode, @Getter/ @Setter and @RequiredArgsConstructor

@Accessors

@Accessors 主要用于控制生成的getter和setter
主要参数介绍

@Accessors mainly used to control generation of key parameters

• fluent boolean值，默认为false。此字段主要为控制生成的getter和setter方法前面是否带get/set
• chain boolean值，默认false。如果设置为true，setter返回的是此对象，方便链式调用方法
• prefix 设置前缀 例如：@Accessors(prefix="abc") private String abcAge 当生成get/set方法时，会把此前缀去掉

@Synchronized

给方法加上同步锁

Put a synchronised lock on the method.

@Wither

提供了给final字段赋值的一种方法

It provides a way to give value to the final field.

@onX

在注解里面添加注解的方式

How to add an annotation to the note.

直接看代码

Look directly at the code.

@Builder

@Builder注释为你的类生成复杂的构建器API。
lets you automatically produce the code required to have your class be instantiable with code such as:

@Builder comments to generate complex builders for your class API.

直接看官方示例，对比一下就都明白了

Just look at the official example and we'll see.

@Delegate

这个注解也是相当的牛逼，看下面的截图，它会该类生成一些列的方法，这些方法都来自与List接口

This note is also quite awesome. Look at the screenshot below. It creates some sort of column approach, all of which comes from interfaces with List.

附带一个我使用的例子

就介绍这么多了，更多的注解请看官方文档

虽然默认配置已经可以使用SpringMVC了，不过我们有时候需要进行自定义配置。
可以在 application.yml 文件中配置日志级别控制：

Although the default configuration is already available using SpringMVC, we sometimes need custom configuration.
Configure log level control in application.yml files:

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