使用DOM创建xml文件

使用DOM创建xml文件

创建xml的代码如下：

public class CreateXML {

  public static void main(String[] args) {
    DocumentBuilderFactory factory =DocumentBuilderFactory.newInstance();
    try {
      
      DocumentBuilder builder=factory.newDocumentBuilder();
      Document documnet= builder.newDocument();
      Element root=documnet.createElement("languages");
      root.setAttribute("cat", "it");
      
      Element lan1=documnet.createElement("lan");
      lan1.setAttribute("id", "1");
      Element name1=documnet.createElement("name");
      name1.setTextContent("java");
      Element ide1=documnet.createElement("ide");
      ide1.setTextContent("eclipse");
      lan1.appendChild(name1);
      lan1.appendChild(ide1);
      
      Element lan2=documnet.createElement("lan");
      lan2.setAttribute("id", "2");
      Element name2=documnet.createElement("name");
      name2.setTextContent("c#");
      Element ide2=documnet.createElement("ide");
      ide2.setTextContent("visual studio");
      lan2.appendChild(name2);
      lan2.appendChild(ide2);
      
      Element lan3=documnet.createElement("lan");
      lan3.setAttribute("id", "3");
      Element name3=documnet.createElement("name");
      name3.setTextContent("swift");
      Element ide3=documnet.createElement("ide");
      ide3.setTextContent("visual studio");
      lan3.appendChild(name3);
      lan3.appendChild(ide3);
      
      root.appendChild(lan1);
      root.appendChild(lan2);
      root.appendChild(lan3);
      documnet.appendChild(root);
      
      //使用transformer将xml文档转换成其他格式
      TransformerFactory tfactory=TransformerFactory.newInstance();
      Transformer former=tfactory.newTransformer();
      
      //将xml内容以字符串输出
      StringWriter writer=new StringWriter();
      former.transform(new DOMSource(documnet), new StreamResult(writer));
      System.out.println(writer.toString());
      
      //将xml内容保存为文件
      former.transform(new DOMSource(documnet), new StreamResult(new File("newxml.xml")));

    } catch (ParserConfigurationException e) {
      e.printStackTrace();
    } catch (TransformerConfigurationException e) {
      e.printStackTrace();
    } catch (TransformerException e) {
      e.printStackTrace();
    }

  }

}

将xml的内容放入document对象后，直接把这document用toString输出会是null

此时需要进行使用Transformer进行转换，如果想变成字符串输出可以借助stringwriter，如果想变成文件保存直接用file

备注：eclipse中可以用ctrl+i进行格式化xml文件，更易于观察