將Xml文檔寫入文件以保存黑莓中的更改

Question

我試圖在黑莓中解析Xml。我將xml複製到SD卡。我試過這段代碼，我成功了。我試圖插入新的標籤（節點）到XML和它的作品，但他們被添加到文件的結尾，但我不知道這是否是最好的方式來做到這一點，但我怎麼能寫Xml文檔到該文件保存更改？

DocumentBuilderFactory docBuilderFactory= DocumentBuilderFactory. newInstance(); 
DocumentBuilder docBuilder= docBuilderFactory.newDocumentBuilder(); 
docBuilder.isValidating(); 
doc = docBuilder.parse(conn.openInputStream()); 
InsertBlock(doc); 
doc.getDocumentElement().normalize(); 
NodeList list=doc.getElementsByTagName("*"); 
node=new String(); 
element = new String(); 

for (int i=0;i<list.getLength();i++){ 
     Node value=list.item(i).getChildNodes().item(0); 
     node=list.item(i).getNodeName(); 
     element=value.getNodeValue(); 
} 

並插入新節點：

Node emp=myDocument.createElement("Emp"); 
Text NodeText = myDocument.createTextNode("DD"); 
emp.appendChild(NodeText); 
myDocument.appendChild(emp); 

Answer 1

爲了插入新節點（一個或多個），你應該使用Node#insertBefore()而不是Node#appendChild()。檢查文檔here。

更換

Node emp=myDocument.createElement("Emp"); 
Text NodeText = myDocument.createTextNode("DD"); 
emp.appendChild(NodeText); 
myDocument.appendChild(emp); 

與

Node emp=myDocument.createElement("Emp"); 
Text NodeText = myDocument.createTextNode("DD"); 
emp.appendChild(NodeText); 
myDocument.insertBefore(emp, someExistingNode); 

凡someExistingNode是Node（可能Element）要添加新的NodeEMP之前這。

編輯1：如何編寫XML提交

try { 
    String filePath = "file:///store/home/user/XmlFile.xml"; 
    FileConnection fc = (FileConnection) Connector.open(filePath, Connector.READ_WRITE); 
    if (!fc.exists()) { 
     fc.create(); // create the file if it doesn't exist 
    } else { 
     fc.truncate(0); // truncate the file if it exists 
    } 

    OutputStream os = fc.openOutputStream(); 
    XMLWriter xmlWriter = new XMLWriter(os); 
    xmlWriter.setPrettyPrint(); 
    DOMInternalRepresentation.parse(myDocument, xmlWriter); 
    os.close(); 
    fc.close(); 

} catch (Exception e) { 
    // Place exception handling code here 
} 

編輯2：節點插入和XML到文件中寫入

try { 
    // Creating document 
    Document myDocument = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument(); 

    Element parentElement = myDocument.createElement("parentTag"); 

    // create first element and append it to parent 
    Element firstElement = myDocument.createElement("firstElement"); 
    firstElement.appendChild(myDocument.createTextNode("1")); 
    parentElement.appendChild(firstElement); 

    // create third element and append it to parent 
    Element thirdElement = myDocument.createElement("thirdElement"); 
    thirdElement.appendChild(myDocument.createTextNode("3")); 
    parentElement.appendChild(thirdElement); 

    // create second element and insert it between first and third elements 
    Element secondElement = myDocument.createElement("secondElement"); 
    secondElement.appendChild(myDocument.createTextNode("2")); 
    parentElement.insertBefore(secondElement, thirdElement); 

    myDocument.appendChild(parentElement); 

    // Writing document to file 
    String filePath = "file:///store/home/user/XmlFile.xml"; 
    FileConnection fc = (FileConnection) Connector.open(filePath, Connector.READ_WRITE); 
    if (!fc.exists()) { 
     fc.create(); // create the file if it doesn't exist 
    } else { 
     fc.truncate(0); // truncate the file if it exists 
    } 

    OutputStream os = fc.openOutputStream(); 
    XMLWriter xmlWriter = new XMLWriter(os); 
    xmlWriter.setPrettyPrint(); 
    DOMInternalRepresentation.parse(myDocument, xmlWriter); 
    os.close(); 
    fc.close();    

} catch (ParserConfigurationException e) { 
    e.printStackTrace(); 
} catch (IOException e) { 
    e.printStackTrace(); 
} catch (SAXException e) { 
    e.printStackTrace(); 
}  

添加的代碼示例還檢查this question關於在BlackBerry上創建XML。