XML解析以计算空值的数量

Question

我是安卓新手。我需要解析 XML 来计算标签中空值的数量。

例如，下面的 XML 文件中有 3 本书，我想计算未提及到期日期（标签 dc:duedate/）的位置/标签为空，因此它返回结果为 2。有人可以建议吗？非常感谢。

This XML file does not appear to have any style information associated with it. The document tree is shown below.
<zs:searchRetrieveResponse xmlns:zs="http://www.loc.gov/zing/srw/">
<zs:version>1.1</zs:version>
<zs:numberOfRecords>1</zs:numberOfRecords>
<zs:records>
<zs:record>
<zs:recordSchema>dc</zs:recordSchema>
<zs:recordPacking>xml</zs:recordPacking>
<zs:recordData>
<dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:title>
Access to knowledge in the age of intellectual property /
</dc:title>
<dc:creator>Kapczynski, Amy.</dc:creator>
<dc:creator>Krikorian, Gaëlle, 1972-</dc:creator>
<dc:type>text</dc:type>
<dc:publisher>New York : Zone Books,</dc:publisher>
<dc:date>2010.</dc:date>
<dc:language>eng</dc:language>
<dc:description>Includes bibliographical references.</dc:description>
<dc:subject>Intellectual property.</dc:subject>
<dc:subject>Access to knowledge movement.</dc:subject>
<dc:subject>Freedom of information.</dc:subject>
<dc:barcode>B1246855</dc:barcode>
<dc:duedate/>
<dc:barcode>B1246854</dc:barcode>
<dc:duedate/>
<dc:barcode>B1246853</dc:barcode>
<dc:duedate>2015-12-31</dc:duedate>
</dc:dc>
</zs:recordData>
<zs:recordPosition>1</zs:recordPosition>
</zs:record>
</zs:records>
</zs:searchRetrieveResponse>

我正在使用

DocumentBuilder builder = null;

    try {
        builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
        InputSource src = new InputSource();
        src.setCharacterStream(new StringReader(response));

        Document doc = builder.parse(src);

        NodeList list = doc.getElementsByTagName("dc:duedate");



        Toast.makeText(getActivity().getApplicationContext(), "Total : " + list.getLength() 
                ,Toast.LENGTH_LONG).show();

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

但它返回 3，我希望它是 2。

Answer 1

请看看下面的代码是否有帮助：

try {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        // use the factory to create a documentbuilder
        DocumentBuilder builder = factory.newDocumentBuilder();

        // create a new document from input source
        String response="<zs:searchRetrieveResponse xmlns:zs=\"http://www.loc.gov/zing/srw/\">\n" +
                "<zs:version>1.1</zs:version>\n" +
                "<zs:numberOfRecords>1</zs:numberOfRecords>\n" +
                "<zs:records>\n" +
                "<zs:record>\n" +
                "<zs:recordSchema>dc</zs:recordSchema>\n" +
                "<zs:recordPacking>xml</zs:recordPacking>\n" +
                "<zs:recordData>\n" +
                "<dc:dc xmlns:dc=\"http://purl.org/dc/elements/1.1/\">\n" +
                "<dc:title>\n" +
                "Access to knowledge in the age of intellectual property /\n" +
                "</dc:title>\n" +
                "<dc:creator>Kapczynski, Amy.</dc:creator>\n" +
                "<dc:creator>Krikorian, Gaëlle, 1972-</dc:creator>\n" +
                "<dc:type>text</dc:type>\n" +
                "<dc:publisher>New York : Zone Books,</dc:publisher>\n" +
                "<dc:date>2010.</dc:date>\n" +
                "<dc:language>eng</dc:language>\n" +
                "<dc:description>Includes bibliographical references.</dc:description>\n" +
                "<dc:subject>Intellectual property.</dc:subject>\n" +
                "<dc:subject>Access to knowledge movement.</dc:subject>\n" +
                "<dc:subject>Freedom of information.</dc:subject>\n" +
                "<dc:barcode>B1246855</dc:barcode>\n" +
                "<dc:duedate/>\n" +
                "<dc:barcode>B1246854</dc:barcode>\n" +
                "<dc:duedate/>\n" +
                "<dc:barcode>B1246853</dc:barcode>\n" +
                "<dc:duedate>2015-12-31</dc:duedate>\n" +
                "</dc:dc>\n" +
                "</zs:recordData>\n" +
                "<zs:recordPosition>1</zs:recordPosition>\n" +
                "</zs:record>\n" +
                "</zs:records>\n" +
                "</zs:searchRetrieveResponse>";


        InputSource src = new InputSource();
        src.setCharacterStream(new StringReader(response));

        Document doc = builder.parse(src);

        NodeList nodes = doc.getElementsByTagName("dc:duedate");
        // print the text content of each child
        int cnt=0;
        for (int i = 0; i < nodes.getLength(); i++) {
            if(nodes.item(i).getTextContent().trim().isEmpty()){
                cnt++;
            }

        }
        Log.e("TAGLOG","" + cnt);
    }catch (Exception e){

    }

在我身边工作。请看看有没有帮助。