使用Java替換XML元素

Question

在下面的XML中，我想要使用Java更改<密碼>元素的值。

<?xml version="1.0" encoding="UTF-8"?> 
<ns1:Envelope xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns2="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> 
    <ns1:Header> 
     <ns2:Security> 
      <ns2:UsernameToken xmlns:ns3="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> 
      <ns2:Username>ADMIN</ns2:Username> 
      <ns2:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">abcd</ns2:Password> 
      <ns3:Created>2016-09-08T17:47:05.079Z</ns3:Created> 
      </ns2:UsernameToken> 
     </ns2:Security> 
    </ns1:Header> 
    <ns1:Body> 
    </ns1:Body> 
</ns1:Envelope> 

我試着用下面的代碼：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
DocumentBuilder builder = factory.newDocumentBuilder(); 
Document doc = builder.parse(new File("D:/test.xml")); 
Element root = doc.getDocumentElement(); 
root.getElementsByTagName("Password").item(0).setTextContent("efgh"); 

但我得到的NullPointerException。這是因爲getElementsByTagName正在返回一個包含0個元素的NodeList。我嘗試使用getElementsByTagNameNS來代替，但結果仍然相同。

root.getElementsByTagNameNS("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd", "Password").item(0).setTextContent("efgh"); 

我還能做什麼？提前致謝。

Answer 1

你需要設置你的DocumentBuilderFactory是名稱空間感知的：

public static void main(String[] args) throws Exception { 
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
    factory.setNamespaceAware(true); 
    DocumentBuilder builder = factory.newDocumentBuilder(); 
    Document doc = builder.parse(new File("D:/test.xml")); 
    Element root = doc.getDocumentElement(); 
    root.getElementsByTagNameNS("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd", "Password").item(0).setTextContent("efgh"); 

    // Write out result to check it 
    TransformerFactory tFactory = TransformerFactory.newInstance(); 
    Transformer transformer = tFactory.newTransformer(); 
    DOMSource source = new DOMSource(doc); 
    StreamResult result = new StreamResult(System.out); 
    transformer.transform(source, result); 
}