將用戶輸入寫入XML文件

Question

我正在研究JSP中的一個項目。 現在，我的程序成功從XML文件中提取內容並將它們輸出到div中。 我也有一些讀取用戶輸入的文本框。 我正在嘗試將XML文件的內容更新為用戶輸入到文本框中的內容，然后調用Names（）方法將更新文件的內容輸出到div中（替換舊內容）。 但是，我的XML文件沒有更新，我不確定如何執行此操作。 這是我的代碼：

<script src ="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script> 
 <div id ="nameDiv"></div>
<div id = "nameInput">

  <input type = "text" name = "nameOne"  value = "Enter a Name" onClick = "if(this.value == 'Enter a Name'){this.value = '';}" /> 
 <input type = "text" name="nameTwo"  value = "Enter a Name" onClick = "if(this.value == 'Enter a Name'){this.value = '';}" /> 
  <input type ="text"  name = "nameThree"  value = "Enter a Name" onClick = "if(this.value == 'Enter a Name'){this.value = '';}" /> 
  <input type = "button" name = "btnUpdate" value = "Update Name" /></div> 

<% String name1 = request.getParameter("nameOne");
 String name2 = request.getParameter("nameTwo");
 String name3 = request.getParameter("nameThree");
 File file  = new File("Employees.xml");

 public void updateXML(){

      if(name1 ! = '' || name2 != '' || name3 != ''){

         try{
          DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
          DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
          Document document = documentBuilder.parse(file);

          Node firstNameLine = document.getElementsByTagName("People").item(0);
          Node secNameLine = document.getElementsByTagName("People").item(1);
          Node thirdNameLine = document.getElementsByTagName("People").item(2);

          firstNameLine.setText(name1);
          secNameLine.setText(name2);
          thirdNameLine.setText(name3);

          TransformerFactory transformerFactory = TransformerFactory.newInstance();
          Transformer transformer = transformerFactory.newTransformer();
          transformer.setOutputProperty(OutputKeys.INDENT, "yes");
          StringWriter sw = new StringWriter();
          StreamResult result = new StreamResult(sw);
          DOMSource domSource = new DOMSource(document);

          transformer.transform(domSource, result);
          String xmlString = sw.toString();
          FileWriter fw=new FileWriter(file,true);
          BufferedWriter bw = new BufferedWriter(fw);
          bw.write(xmlString);
          bw.flush();
          bw.close();
          }
          catch(Exception e)
          {

         }
      }
     }
         public void buttonOnClick () throws ServletException, IOException {

             if (request.getParameter("btnUpdate") != null) {
              updateXML();
           }
        }
   %>

function getOutput()
{
  if (xmlhttp.readyState==4)
  {
  document.getElementById("nameInput").innerHTML=xmlhttp.responseText;
  }
}

function loadXMLDoc(dname) {


              if (window.XMLHttpRequest) {
                  xmlhttp = new XMLHttpRequest();
              }

              else {
                  xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
              }

               xmlDoc.async = false;
                 xmlDoc.load(dname);
                xmlDoc.save("Employees.xml");
                return (xmlDoc);
         }

 function Names() {
      var xml = getXML();
      var txt = "";
      $(xml).find("Person").each(function () {
        txt += "<div>" + $(this).text() + "</div>";
      });
      $("body").append(txt);
    }

    Names();

我的XML文件：

<People>
  <Person>George</Person>
<Person>Mary</Person>
<Person>John</Person>
</People>

現在，每當我點擊更新按鈕時，我只是將舊文件的內容一遍又一遍地“粘貼”到div上。 它不會發布用戶輸入。 我哪里錯了？ 任何幫助，將不勝感激。

Answer 1

您確定表單實際上已提交嗎？ <input type = "button"不會自行提交表單。 嘗試更改type屬性以submit ：

<input type = "submit" name = "btnUpdate" value = "Update Name" /></div> 

Answer 2

我已經嘗試過這個例子來更新表格中輸入數據的人的數據。如果對你有幫助，請查看這個。

<%@page import="org.w3c.dom.Node"%>
<%@page import="org.w3c.dom.NodeList"%>
<%@page import="java.io.InputStreamReader"%>
<%@page import="java.io.FileOutputStream"%>
<%@page import="java.io.BufferedReader"%>
<%@page import="java.io.FileReader"%>
<%@page import="org.w3c.dom.Attr"%>
<%@page import="javax.xml.transform.TransformerFactory"%>
<%@page import="javax.xml.transform.Transformer"%>
<%@page import="javax.xml.transform.dom.DOMSource"%>
<%@page import="javax.xml.transform.stream.StreamResult"%>
<%@page import="java.io.File"%>
<%@page import="org.w3c.dom.Element"%>
<%@page import="org.w3c.dom.Document"%>
<%@page import="javax.xml.parsers.DocumentBuilderFactory"%>
<%@page import="javax.xml.parsers.DocumentBuilder"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<%

    DocumentBuilderFactory dbfact = DocumentBuilderFactory.newInstance();
    try {

        String ufname = request.getParameter("fname");
        String ulname = request.getParameter("lname");

        DocumentBuilder docbuilder = dbfact.newDocumentBuilder();

        Document doc = docbuilder.newDocument();
        Element rootElement = doc.createElement("People");
        doc.appendChild(rootElement);

        Element staff = doc.createElement("staff");
        rootElement.appendChild(staff);

        Attr attr = doc.createAttribute("id");
        attr.setValue("1");

        Element firstname = doc.createElement("person");
        firstname.appendChild(doc.createTextNode(ufname));
        staff.appendChild(firstname);

        /*Element firstname1 = doc.createElement("person");
        firstname1.appendChild(doc.createTextNode("Mahesh"));
        staff.appendChild(firstname1);*/

        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(new File("D:\\file.xml"));

        transformer.transform(source, result);

        System.out.println("File saved!");

%>

<%

    File fXmlFile = new File("D:\\file.xml");

    Document docs = docbuilder.parse(fXmlFile);
    docs.getDocumentElement().normalize();
    System.out.println("Root element :" + docs.getDocumentElement().getNodeName());

    NodeList nList = docs.getElementsByTagName("staff");
    for (int temp = 0; temp < nList.getLength(); temp++) {
        Node nNode = nList.item(temp);
        System.out.println("\nCurrent Element :" + nNode.getNodeName());
        if (nNode.getNodeType() == Node.ELEMENT_NODE) {
            Element eElement = (Element) nNode;
%>
<%=eElement.getElementsByTagName("person").item(0).getTextContent()%>
<%
        }
    }
%>
<%

 } catch (Exception e) {
 System.out.println("Exception" + e);
}
%>