附加xml文件時出現<xml version =「1.0」encoding =「UTF-8」standalone =「no」？>

Question

我正在嘗試編寫一個函數，用於存儲名稱和出生日期一個.xml文件。代碼應該看看.xml文件是否已經存在。當文件不存在時，會創建一個新的.xml文件並輸入數據。但是當第二次調用該函數時，追加時會出現一個雜散。請讓我知道如何解決這個問題。我是新來的java和XML解析，我今天剛剛開始。使用XML創建和追加交易功能是xmlCreator（） 我粘貼下面

import java.awt.*; 
    import java.awt.event.ActionEvent; 
    import java.awt.event.ActionListener; 
    import javax.swing.*; 
    import java.io.FileWriter; 
    import java.nio.file.*; 
    import javax.xml.parsers.DocumentBuilder; 
    import javax.xml.parsers.DocumentBuilderFactory; 
    import javax.xml.transform.OutputKeys; 
    import javax.xml.transform.Transformer; 
    import javax.xml.transform.TransformerFactory; 
    import javax.xml.transform.dom.DOMSource; 
    import javax.xml.transform.stream.StreamResult; 
    import org.w3c.dom.Document; 
    import org.w3c.dom.Element; 
    public class Exercise1 extends JPanel implements ActionListener{ 


    String name; 
    String dateOfBirth; 

//Labels to identify the fields 
JLabel nameLabel; 
JLabel dateOfBirthLabel; 

//Strings for the labels 
static String nameString = "Name"; 
static String dateOfBirthString = "Date Of Birth (dd/mm/yyyy)"; 

JTextField nameField; 
JTextField dateOfBirthField; 

JButton clearButton; 
JButton saveAndProceedButton; 
JButton bdayInNext5Days; 

int serialNumber = 0; 
FileWriter xmlFile; 

public Exercise1() 
{ 
super (new BorderLayout()); 

nameLabel = new JLabel(nameString); 
dateOfBirthLabel = new JLabel(dateOfBirthString); 

nameField = new JTextField(); 
nameField.setColumns(20); 
nameLabel.setLabelFor(nameField); 

dateOfBirthField = new JTextField(); 
dateOfBirthField.setColumns(20); 
dateOfBirthLabel.setLabelFor(dateOfBirthField); 

//Lay out the labels in a panel. 
JPanel labelPane = new JPanel(new GridLayout(0,1)); 
labelPane.add(nameLabel); 
labelPane.add(dateOfBirthLabel); 

//Layout the text fields in a panel. 
JPanel fieldPane = new JPanel(new GridLayout(0,1)); 
fieldPane.add(nameField); 
fieldPane.add(dateOfBirthField); 

clearButton = new JButton ("Clear"); 
clearButton.addActionListener (this); 

saveAndProceedButton = new JButton ("Save and Proceed"); 
saveAndProceedButton.addActionListener (this); 
serialNumber++; 

bdayInNext5Days = new JButton("Bday in next 5 days"); 
bdayInNext5Days.addActionListener (this); 
//Put the panels in this panel, labels on left, 
//text fields on right. 
add(labelPane, BorderLayout.LINE_START); 
add(fieldPane, BorderLayout.CENTER); 
add(clearButton, BorderLayout.LINE_END); 
add(saveAndProceedButton, BorderLayout.SOUTH); 
add(bdayInNext5Days, BorderLayout.NORTH); 
} 

/** 
    * Create the GUI and show it. For thread safety, 
    * this method should be invoked from the 
    * event dispatch thread. 
    */ 
private static void createAndShowGUI() { 
    //Create and set up the window. 
    JFrame frame = new JFrame("Exercise 1"); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

    //Add contents to the window. 
    frame.add(new Exercise1()); 

    //Display the window. 
    frame.pack(); 
    frame.setVisible(true); 
} 

private void xmlCreator(String name, String dateOfBirth) throws Exception{ 

    Path path = Paths.get("Bday.xml"); 
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance(); 
    DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder(); 
    Document document = null; 
    Element element = null; 
    Transformer transformer = null; 
    TransformerFactory transformerFactory = null; 

    if(Files.exists(path)) { 
     xmlFile = new FileWriter("Bday.xml",true); 
     document = documentBuilder.parse("Bday.xml"); 
     element = document.getDocumentElement(); 
    } 
    else{ 
     xmlFile = new FileWriter("Bday.xml",true); 
     document = documentBuilder.newDocument(); 
     element = document.createElement("Birthday"); 
     document.appendChild(element); 
    } 
    Element Id = document.createElement("Id"); 
    Id.appendChild(document.createTextNode(Integer.toString(serialNumber))); 
    element.appendChild(Id); 

    Element xmlName = document.createElement("Name"); 
    xmlName.appendChild(document.createTextNode(name)); 
    Id.appendChild(xmlName); 

    Element xmldateOfBirth = document.createElement("Date_Of_Birth"); 
    xmldateOfBirth.appendChild(document.createTextNode(dateOfBirth)); 
    Id.appendChild(xmldateOfBirth); 

    DOMSource source = new DOMSource(document); 
    transformerFactory = TransformerFactory.newInstance(); 
    transformer = transformerFactory.newTransformer(); 
    transformer.setOutputProperty(OutputKeys.INDENT, "yes"); 

    StreamResult streamResult = new StreamResult(xmlFile); 

    transformer.transform(source, streamResult); 

} 
public void actionPerformed(ActionEvent e) { 
     Object source = e.getSource(); 

     if (source == clearButton){ 
      nameField.setText(""); 
      dateOfBirthField.setText(""); 
     } 
     else if(source == saveAndProceedButton){ 
      name = nameField.getText(); 
      dateOfBirth = dateOfBirthField.getText(); 
      try { 
       xmlCreator(name,dateOfBirth); 
      } catch (Exception e1) { 
       // TODO Auto-generated catch block 
       e1.printStackTrace(); 
      } 
      nameField.setText(""); 
      dateOfBirthField.setText(""); 
      serialNumber++; 
     } 
     else{ 


     } 


    } 


public static void main (String[] args) 
{ 
     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 
       //Turn off metal's use of bold fonts 
       UIManager.put("swing.boldMetal", Boolean.FALSE); 
       createAndShowGUI(); 
      } 
     }); 
}} 

輸出存儲在.xml文件的代碼如下

<?xml version="1.0" encoding="UTF-8" standalone="no"?> 
<Birthday> 
<Id>1<Name>asdasd</Name> 
<Date_Of_Birth>123</Date_Of_Birth> 
</Id> 
</Birthday> 
<?xml version="1.0" encoding="UTF-8" standalone="no"?> 
<Birthday> 
<Id>1<Name>asdasd</Name> 
<Date_Of_Birth>123</Date_Of_Birth> 
</Id> 
<Id>2<Name>adss</Name> 
<Date_Of_Birth>12</Date_Of_Birth> 
</Id> 

Answer 1

給出你不需要FileWriter來寫入xml。當您向StreamResult提供文件時，轉換器將處理它。

下面是解決您的問題代碼：

if(Files.exists(path)) { 
     document = documentBuilder.parse("Bday.xml"); 
     element = document.getDocumentElement(); 
} 
else{ 
     document = documentBuilder.newDocument(); 
     element = document.createElement("Birthday"); 
     document.appendChild(element); 
} 
Element Id = document.createElement("Id"); 

Id.appendChild(document.createTextNode(Integer.toString(serialNumber))); 
element.appendChild(Id); 

Element xmlName = document.createElement("Name"); 
xmlName.appendChild(document.createTextNode(name)); 
Id.appendChild(xmlName); 

Element xmldateOfBirth = document.createElement("Date_Of_Birth"); 
xmldateOfBirth.appendChild(document.createTextNode(dateOfBirth)); 
Id.appendChild(xmldateOfBirth); 

DOMSource source = new DOMSource(document); 
transformerFactory = TransformerFactory.newInstance(); 
transformer = transformerFactory.newTransformer(); 
transformer.setOutputProperty(OutputKeys.INDENT, "yes"); 

StreamResult streamResult = new StreamResult(new File("Bday.xml")); 
transformer.transform(source, streamResult); 

我提出要刪除FileWriter部分和使用StreamResult與new File(...)