Question

val pets = 
<Pet>
<Cat>black
<Kitty>small</Kitty>
<Kitty>big</Kitty>
<Kitty>large</Kitty>
</Cat>
<Dog>grey
<Kitty>large</Kitty>
</Dog>
</Pet>

在这里，我需要更改（更新/删除）子节点的<Kitty>{text}</Kitty>＆＃34; Cat＆＃34;在scala中为<baby>{text}</baby>！

到目前为止，我已尝试过这个，

class xml_class{
    def replace(elem:Elem):Elem=elem.copy(
      child = elem.child.map{
         case elem: Elem if elem.label=="Cat" => <Kitty>{elem}</Kitty>
         case elem: Elem => replace(elem)
         case other => other
       }
    )}

var ob =new xml_class()
println(ob.replace(pets))

将输出as，

<Pet>
<Cat>black
<baby>small</baby>
<baby>big</baby>
<baby>large</baby>
</Cat>
<Dog>grey
<baby>large</baby>
</Dog>
</Pet>

因此它实际上更改了<kitty>中的所有<Cat> & <Dog>标记，而我只需要根据XPATH条件或{@ p>更改<Cat>。{/ p>

Answer 1

如果我的理解是正确的，您需要将Cat子标签从Kitty更改为baby。

class xml_class {
    def replace(elem: Elem): Elem = {
      elem.copy(child = elem.child.map {
        case catEle: Elem if catEle.label == "Cat" =>
          catEle.copy(child = catEle.child.map {
            case cc: Elem if cc.label == "Kitty" => cc.copy(label = "baby")
            case innerOther => innerOther
          })
        case other => other
      })
    }
  }

输出如下：

<Pet>
      <Cat>black
        <baby>small</baby>
        <baby>big</baby>
        <baby>large</baby>
      </Cat>
      <Dog>grey
        <Kitty>large</Kitty>
      </Dog>
    </Pet>

Answer 2

scala-xml库有一种定义重写规则的方法：

val kittyToBabyRule = new scala.xml.transform.RewriteRule {
  override def transform(n: Node): Seq[Node] = n match {
    case <Kitty>{text}</Kitty> => <baby>{text}</baby>
    case _ => n
  }
}

val kittyTransformer = new scala.xml.transform.RuleTransformer(kittyToBabyRule)

然后您可以在重写规则中使用重写规则：

val catRule = new scala.xml.transform.RewriteRule {
  override def transform(n: Node): Seq[Node] = n match {
    case e: Elem if e.label == "Cat" => kittyTransformer(n)
    case _ => n
  }
}

然后，您可以使用顶级规则创建变换器：

val catTransformer = new scala.xml.transform.RuleTransformer(catRule)

然后您可以将变压器运行为：

scala> catTransformer(doc)
res0: scala.xml.Node =
<Pet>
<Cat>black
<baby>small</baby>
<baby>big</baby>
<baby>large</baby>
</Cat>
<Dog>grey
<Kitty>large</Kitty>
</Dog>
</Pet>

在SCALA中更新/删除XML节点（标记）

2 个答案: