如何使用Python为XML父节点添加子节点（含结构调整示例）

场景1：从JSON转XML时直接调整结构 #

如果你的XML是从JSON转换而来，先调整JSON数据结构再生成XML会更高效。假设原始JSON数据如下：

{
  "PLMRequest": {
    "StyleNumber": "ST123",
    "StyleName": "Summer Dress",
    "Theme": "Beachwear",
    "ProductSpecialist": "John Doe",
    "Color": [
      {"Code": "BLU", "Name": "Blue"},
      {"Code": "RED", "Name": "Red"}
    ],
    "Description": "Lightweight cotton dress for summer"
  }
}

修改后的JSON转XML代码如下：

import json
import xml.etree.ElementTree as ET

def json_to_plm_xml(json_data):
    plm_data = json_data["PLMRequest"]
    root = ET.Element("PLMRequest")

    # 创建Overview节点并迁移指定字段
    overview = ET.SubElement(root, "Overview")
    overview_fields = ["StyleNumber", "StyleName", "Theme", "ProductSpecialist"]
    for field in overview_fields:
        if field in plm_data:
            elem = ET.SubElement(overview, field)
            elem.text = str(plm_data[field])
            del plm_data[field]  # 移除已处理字段，避免重复生成

    # 创建ColorInfo节点并迁移所有Color项
    color_info = ET.SubElement(root, "ColorInfo")
    if "Color" in plm_data:
        # 兼容单个Color对象或Color列表的情况
        colors = plm_data["Color"] if isinstance(plm_data["Color"], list) else [plm_data["Color"]]
        for color in colors:
            color_elem = ET.SubElement(color_info, "Color")
            for key, val in color.items():
                sub_elem = ET.SubElement(color_elem, key)
                sub_elem.text = str(val)
        del plm_data["Color"]

    # 处理剩余未迁移的节点
    for key, val in plm_data.items():
        elem = ET.SubElement(root, key)
        elem.text = str(val)

    # 格式化XML缩进（Python 3.9+支持）
    ET.indent(root)
    return ET.tostring(root, encoding="utf-8", xml_declaration=True).decode("utf-8")

# 示例调用
if __name__ == "__main__":
    raw_json = '''{
      "PLMRequest": {
        "StyleNumber": "ST123",
        "StyleName": "Summer Dress",
        "Theme": "Beachwear",
        "ProductSpecialist": "John Doe",
        "Color": [{"Code": "BLU", "Name": "Blue"}, {"Code": "RED", "Name": "Red"}],
        "Description": "Lightweight cotton dress for summer"
      }
    }'''
    xml_result = json_to_plm_xml(json.loads(raw_json))
    print(xml_result)

关键逻辑说明 #

1. 先创建Overview节点，遍历指定的字段，将对应的JSON值生成子节点并移入Overview，同时删除原JSON中的这些字段，避免重复生成节点。
2. 处理Color字段时，先统一转为列表（兼容单个/多个Color的情况），逐个生成Color节点并移入ColorInfo，同样删除原JSON中的Color字段。
3. 最后处理剩余的其他字段，直接添加到PLMRequest根节点下。

场景2：直接修改已有的XML文件 #

如果已经有现成的XML文件，可直接操作XML节点完成迁移。假设现有XML结构如下：

<PLMRequest>
  <StyleNumber>ST123</StyleNumber>
  <StyleName>Summer Dress</StyleName>
  <Theme>Beachwear</Theme>
  <ProductSpecialist>John Doe</ProductSpecialist>
  <Color>
    <Code>BLU</Code>
    <Name>Blue</Name>
  </Color>
  <Color>
    <Code>RED</Code>
    <Name>Red</Name>
  </Color>
  <Description>Lightweight cotton dress for summer</Description>
</PLMRequest>

修改XML结构的代码如下：

import xml.etree.ElementTree as ET

def restructure_plm_xml(input_path, output_path):
    tree = ET.parse(input_path)
    root = tree.getroot()

    # 创建Overview节点并迁移指定节点
    overview = ET.SubElement(root, "Overview")
    target_nodes = ["StyleNumber", "StyleName", "Theme", "ProductSpecialist"]
    for node_name in target_nodes:
        nodes = root.findall(node_name)
        for node in nodes:
            overview.append(node)  # append会自动将节点从原父节点移除

    # 创建ColorInfo节点并迁移所有Color节点
    color_info = ET.SubElement(root, "ColorInfo")
    color_nodes = root.findall("Color")
    for color_node in color_nodes:
        color_info.append(color_node)

    # 格式化并保存修改后的XML
    ET.indent(root)
    tree.write(output_path, encoding="utf-8", xml_declaration=True)

# 示例调用
if __name__ == "__main__":
    restructure_plm_xml("original_plm.xml", "modified_plm.xml")

关键逻辑说明 #

1. 使用findall定位需要迁移的节点，通过append方法将节点移动到新的子节点下（ElementTree中，节点只能属于一个父节点，append后会自动从原父节点移除）。
2. 最后保存修改后的XML文件到指定路径。

内容的提问来源于stack exchange，提问作者Pranit Gursale