yaml文件中星号（*）有什么用？

Question

当我偶然发现这句话时，我正在检查 spring 引导执行器：

* has a special meaning in YAML, so be sure to add quotes if you want to include (or exclude) all endpoints.

我试图通过互联网查看有关它的信息，但没有任何运气。 yaml文件中*有什么用？

Answer 1

*用于去除重复节点。考虑这个 yaml 示例：

myprop:
  uid: &id XXX
myprop1:
  id: *id

以上将展开为：

myprop:
  uid: XXX
myprop1:
  id: XXX

现在尝试运行此代码：

@Value("${myprop.uid}") String uid;
@Value("${myprop1.id}") String id;

@Bean
ApplicationRunner runner() {
    return args -> {
        System.out.println(uid);  // prints "XXX"
        System.out.println(id); // prints "XXX"
        System.out.println(uid.equals(id)); // prints "true"
    };
}

来自spec：

Repeated nodes (objects) are first identified by an anchor (marked with the ampersand - “&”), and are then aliased (referenced with an asterisk - “*”) thereafter.

Answer 2

这取决于 YAML 文件的上下文。你说你 正在经历 spring 引导执行器 ，所以你可以查看 Spring 引导的参考文档，第 5.2.2. Exposing Endpoints 章准确地说。

* can be used to select all endpoints. For example, to expose everything over HTTP except the env and beans endpoints, use the following properties:
management.endpoints.web.exposure.include=*
management.endpoints.web.exposure.exclude=env,beans

星号*表示所有属于某个类别的端点被包含或排除。

下面的句子只是说星号 * 字符必须被引用 "*" 如果 YAML 格式使用经典属性文件。

* has a special meaning in YAML, so be sure to add quotes if you want to include (or exclude) all endpoints, as shown in the following example:

顺便说一句，这句话与您在问题中找到的相同。

yaml文件中星号（*）有什么用？

What is the use of star(*) in yaml file?

spring

spring-boot

yaml

spring-boot-actuator