Snakeyaml 似乎不必要地将简单值包装在列表中

Question

我正在尝试使用 Groovy 和 Snakeyaml 解析以下 YAML 文件（显然我已经清理了数据，但足以证明问题）：

---
info:
  summary: Snakeyaml Issue
examples:
  - 1st example:
      name: Example 1
      sublist:
        - 0.1:
           foo: bar

我希望得到以下陈述：

println resource.info.summary
println resource.examples."1st example".name
println resource.examples."1st example".sublist."0.1"

屈服：

Snakeyaml Issue
Example 1
[foo:bar]

和：

println resource.examples."1st example".sublist."0.1".foo

屈服：

bar

但是，实际输出来自：

println resource.info.summary
println resource.examples."1st example".name
println resource.examples."1st example".sublist."0.1"
println resource.examples."1st example".sublist."0.1".foo

是：

Snakeyaml Issue
[Example 1]
[[[foo:bar]]]
[[bar]]

我只能通过包含列表索引来获得所需的输出：

println resource.info.summary
println resource.examples[0]."1st example".name
println resource.examples[0]."1st example".sublist[0]."0.1"
println resource.examples[0]."1st example".sublist[0]."0.1".foo

这似乎是不必要的。也许我误解了数据的结构？

为了完整起见，我用来说明问题的常规代码如下所示（我从网上抓取了 CustomerResolver 代码，以便将浮点数保持为字符串）：

import org.yaml.snakeyaml.DumperOptions
import org.yaml.snakeyaml.Yaml
import org.yaml.snakeyaml.constructor.Constructor
import org.yaml.snakeyaml.nodes.Tag
import org.yaml.snakeyaml.representer.Representer
import org.yaml.snakeyaml.resolver.Resolver

def fileName = "example.yaml"
def Yaml yaml = new Yaml(new Constructor(), new Representer(), new DumperOptions(),
    new CustomResolver())
def resource = yaml.load(new File(fileName).newInputStream())

println resource.info.summary
println resource.examples."1st example".name
println resource.examples."1st example".sublist."0.1"
println resource.examples."1st example".sublist."0.1".foo

class CustomResolver extends Resolver {

    /*
     * Do not resolve float and timestamp
     */

    protected void addImplicitResolvers() {
        addImplicitResolver(Tag.BOOL, BOOL, "yYnNtTfFoO");
        addImplicitResolver(Tag.INT, INT, "-+0123456789");
        addImplicitResolver(Tag.MERGE, MERGE, "<");
        addImplicitResolver(Tag.NULL, NULL, "~nN\0");
        addImplicitResolver(Tag.NULL, EMPTY, null);

    }
}

有什么想法吗？

Answer 1

问题在于您如何访问 yaml

examples 首先包含 list，然后才包含 object 和键 1st example

对于您的情况，请尝试以下访问：

println resource.info.summary
println resource.examples[0]."1st example"
println resource.examples[0]."1st example".name
println resource.examples[0]."1st example".sublist[0]
println resource.examples[0]."1st example".sublist[0]."0.1"
println resource.examples[0]."1st example".sublist[0]."0.1".foo

要了解列表访问器的工作原理，请查看以下示例：

@Grab(group='org.yaml', module='snakeyaml', version='1.18')
import org.yaml.snakeyaml.Yaml

def Yaml yaml = new Yaml()
def resource = yaml.load(new StringReader('''---
info:
  summary: Snakeyaml Issue
examples:
  - 1st example:
      name: Example 1
  - 1st example:
      name: Example 2
  - 1st example:
      xname: Example 3
  - 2nd example:
      name: Example 4
'''))

println resource.examples."1st example"
//prints>  [[name:Example 1], [name:Example 2], [xname:Example 3], null]

println resource.examples."1st example".name
//prints> [Example 1, Example 2, null]