如何追加使用DOM而不覆盖现有数据的现有XML文件？在java中 [英] How to append an existing XML file using DOM without overwriting the existing data? in java

问题描述

我有一个非常困惑的XML数据如何被追加到已经存在的数据给我你的建议，我的code是这样

i have a very confused about the how the xml data can be append to already existed data give me your suggestions my code is like this

 Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();//db.newDocument();//create document

        Element root = doc.createElement("Employees");//cretae Elements
        doc.appendChild(root);

        Comment cmt = doc.createComment("Employee Details");//Add comment to xml
        root.appendChild(cmt);

        Element employee = doc.createElement("employee");//create Element
        //employee.appendChild(doc.)
        root.appendChild(employee);

        Attr genderAttr = doc.createAttribute("Gender");
        System.out.print("Enter your gender :");
        String gend = br.readLine();
        genderAttr.setValue(gend);
        employee.setAttributeNode(genderAttr);

        System.out.print("Enter first name:");
        String child = br.readLine();
        Element FName = doc.createElement("firstName");
        FName.appendChild(doc.createTextNode(child));//set xml text
        employee.appendChild(FName);

        System.out.print("Enter last name:");
        String child1 = br.readLine();
        Element LName = doc.createElement("lastName");            
        LName.appendChild(doc.createTextNode(child1));
        employee.appendChild(LName);

        //root.appendChild(employee);
        //doc.appendChild(root);

        //to write on file/screen
        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer tr = tf.newTransformer();
        tr.setOutputProperty(OutputKeys.INDENT, "yes");
        DOMSource source = new DOMSource(doc);//source             
        //File shopOrder = new File("src"+File.separator+"xmlparsing"+File.separator+"xmlParse1.xml");//get the file
        StreamResult res = new StreamResult(new File("src"+File.separator+"xmlparsing"+File.separator+"xmlParse1.xml"));//Destination
        tr.transform(source, res);//to write on file

和我可以做轻松地分析和更新也但我不明白我怎么可以追加previous数据，请帮助我

and i can do easily parse and update also but i can't understand how i can append previous data please help me

推荐答案

这是pretty容易。再说了，你想新的员工追加到XML。而不是创建一个新的根你会使用简单的找到它 getElementsByName（）像

It's pretty easy. Say, you want to append new Employees to your XML. Instead of creating a new root you'd simply find it using getElementsByName() like

// find root
NodeList rootList = doc.getElementsByName("Employees");
Node root = rootList.item(0);

Element employee = doc.createElement("employee"); //create new Element
root.appendChild(employee); // append as before

有一个的document.getElementById（）方法，以及，如果一个元素被分配一个标识符，你可以使用。要插入一些深跌树使用的XPath 找到节点首先那么追加（）如常。

There's a Document.getElementById() method as well that you could use if an element has been assigned an identifier. To insert something deep down the tree use XPath to find the node first then append() as usual.

的 修改（样本code加）的

你不能有两个根节点，即两个＆LT;员工与GT; 标记根。这是无效的XML。你需要的是多个＆LT;员工＆GT; 一个单一的根里面标记＆LT;员工与GT; 标记。此外，坚持要么骆驼或死刑案件。我使用的是首都的一致性。

EDIT : (Sample code added)
You can't have two root nodes i.e. two <Employees> tags as root. That's invalid XML. What you need is multiple <Employee> tags inside one single root <Employees> tag. Also, stick to either camel or capital case. I'm using capitals for consistency.

// find root
NodeList rootList = doc.getElementsByName("Employees");
Node root = rootList.item(0);

// append using a helper method
root.appendChild(createEmployee(doc, "male", "John", "Doe"));

public Element createEmployee(Document doc,
                              String gender, String fname, String lname) {
  // create new Employee
  Element employee = doc.createElement("Employee");
  employee.setAttribute("gender", gender);

  // create child nodes
  Element firstName = doc.createElement("FirstName");
  firstName.appendChild(doc.createTextNode(fname));

  Element lastName = doc.createElement("LastName");
  lastName.appendChild(doc.createTextNode(lname));

  // append and return
  employee.appendChild(firstName);
  employee.appendChild(lastName);

  return employee;
}

这篇关于如何追加使用DOM而不覆盖现有数据的现有XML文件？在java中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！