DOM-XML文档中的缺少元素

Question

The XML file contains Employee (with empID, empName, empCode). In some situation empCode is missing.

<Employee><Detail><empID>1</empID><empName>Abhi</empName><empCode>One</empCode>
</Detail>

<Detail><empID>2</empID><empName>Amit</empName>
</Detail>
</Employee>

I am getting the Null pointer Exception while calling the getTagValue() method for "empCode" as there is no tag available with the name in XML.

Java Code :

try { File xmlFile = new File("New.xml");

         DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
            Document doc = dBuilder.parse(xmlFile);
            doc.getDocumentElement().normalize();

            NodeList nList = doc.getElementsByTagName("Detail");
            for (int temp = 0; temp < nList.getLength(); temp++) 
            {
                Node nNode = nList.item(temp);
                if (nNode.getNodeType() == Node.ELEMENT_NODE) 
                {
                    Element eElement = (Element) nNode;
                    EmpDetail empInfo = new EmpDetail();

                    empInfo.SetEmpID(getTagValue("empID", eElement));
                    empInfo.SetEmpName(getTagValue("empName",eElement));
                    empInfo.SetEmpCode(getTagValue("empCode",eElement));

                    DBConnector.SaveinDB(empInfo);
                }

            }
     }
     catch (Exception e) 
     {
         System.out.println("Error: ");
         e.printStackTrace();
     }
 }

 private static String getTagValue(String sTag, Element eElement) 
 {
        NodeList nlList = eElement.getElementsByTagName(sTag).item(0).getChildNodes();
        Node nValue = (Node) nlList.item(0);
        if(nValue == null) 
            return null;
        return insertEscapeSequance(nValue.getNodeValue());
      }

 private static String insertEscapeSequance(String str)
 {
     String returnstr = "";
     String[] strarr = str.split("'");
     returnstr = strarr[0];
     for(int i=1;i<strarr.length;i++)
     {
         returnstr = returnstr + "\\'" + strarr[i];
     }
     return returnstr;
}

Now I want to save the XML data into sql like this :

1 Abhi One 2 Amit null

I tried so many links but not success. Can someone please help me

Answer 1

If this is possible that there is no such value, then simply handle it like that:

if(getTagValue("empCode",eElement) != null){
    empInfo.SetEmpCode(getTagValue("empCode",eElement));
}

Regarding to adding them into SQL, do the same check while creating your statement. As SQL NULL type exists

Answer 2

The problem is caused by eElement.getElementsByTagName(sTag).item(0) . The statement returns the first node specified by sTag . In the case of empCode , null is returned, and calling getChildNodes() will raise a null pointer exception.

Try:

Node node = eElement.getElementsByTagName(sTag).item(0);
if (node != null) {
    Node nValue =  node.getChildNodes().item(0);
    if (nValue != null) {
        return insertEscapeSequance(nValue.getNodeValue());
    }
}
return null;