Java 将用户输入写入XML文件

我正在用JSP做一个项目。现在，我的程序成功地从XML文件中提取内容并将其输出到一个div中。我还有一些文本框可以读取用户输入。我试图将XML文件的内容更新为用户在文本框中输入的内容，然后调用Names（）方法将更新文件的内容输出到div中（替换旧内容）。但是，我的XML文件没有更新，我不确定如何进行更新。这是我的密码：

<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();

函数getOutput（）
{
if（xmlhttp.readyState==4）
{
document.getElementById（“nameInput”）.innerHTML=xmlhttp.responseText；
}
}
函数loadXMLDoc（dname）{
if（window.XMLHttpRequest）{
xmlhttp=新的XMLHttpRequest（）；
}
否则{
xmlhttp=新的ActiveXObject（“Microsoft.xmlhttp”）；
}
xmlDoc.async=false；
xmlDoc.load（dname）；
xmlDoc.save（“Employees.xml”）；
退货（xmlDoc）；
}
函数名（）{
var xml=getXML（）；
var txt=“”；
$（xml）.find（“Person”）.each（函数（）{
txt++=“”+$（this）.text（）+“”；
});
$（“正文”）.append（txt）；
}
名称（）；

我的XML文件：

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

乔治
玛丽
约翰

---

现在，每次我点击更新按钮，我都会一次又一次地将旧文件的内容“粘贴”到div上。它不会发布用户输入。我哪里做错了？如有任何帮助，我们将不胜感激。

您确定表单确实已提交吗？

我尝试了这个示例，用表单中输入的数据更新人员的数据。如果对您有帮助，请查看此示例

<%@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);
}
%>


这是您的代码的全文吗？您是否遗漏了
等指令？这不是我的全部代码（我省略了指令、导入等），因为我认为我的错误与用户输入返回有关。但是我看不出它不起作用的原因（我包括了一个ajax调用）。这件事我已经耽搁了一段时间了。谢谢大家的帮助。谢谢你们的帮助！
<%@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);
}
%>