Question

我正在编写一个程序，该程序从http://www.tcmb.gov.tr/kurlar/today.xml获取每日汇率并将其保存到列表中。这是我的代码：

public class ParseTheXml {

    private List<CurrencyPojo> currencyList;


    public void setCurrencyList(List<CurrencyPojo> currencyList) {
        this.currencyList = currencyList;
    }

    public List<CurrencyPojo> getCurrencyList() throws ParserConfigurationException {
        currencyList = new ArrayList<CurrencyPojo>();

        try {
            DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            URL url = new URL("http://www.tcmb.gov.tr/kurlar/today.xml");
            Document document = builder.parse(url.openStream());

            NodeList nodeList = document.getElementsByTagName("Currency");

            for (int i = 0; i < nodeList.getLength(); i++) { // döngü her currency türü için
                Element element = (Element) nodeList.item(i);
                CurrencyPojo currencyPojoObject = new CurrencyPojo(); 

                currencyPojoObject.setCrossOrder(Integer.parseInt(element.getAttribute("CrossOrder")));
                currencyPojoObject.setKod(element.getAttribute("Kod"));
                currencyPojoObject.setCurrenyCode(element.getAttribute("CurrencyCode"));

                currencyPojoObject.setUnit(Integer.parseInt(element.getElementsByTagName("Unit").item(0).getTextContent()));
                currencyPojoObject.setIsim(element.getElementsByTagName("Isim").item(0).getTextContent());
                currencyPojoObject.setCurrencyName(element.getElementsByTagName("CurrencyName").item(0).getTextContent());
                currencyPojoObject.setForexBuying(Double.parseDouble(element.getElementsByTagName("ForexBuying").item(0).getTextContent()));


       currencyPojoObject.setForexSelling(Double.parseDouble(element.getElementsByTagName("ForexSelling").item(0).getTextContent()));  //  Last 3 codes have Emppty String errors
                currencyPojoObject.setBanknoteBuying(Double.parseDouble(element.getElementsByTagName("BanknoteBuying").item(0).getTextContent()));
                currencyPojoObject.setBanknoteSelling(Double.parseDouble(element.getElementsByTagName("BanknoteSelling").item(0).getTextContent()));

                currencyList.add(currencyPojoObject);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return currencyList;
    }

关于获得ForexSelling，BanknoteBuying和Banknote Selling价值的部分，我得到了

java.lang.NumberFormatException: empty String
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1842)
    at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
    at java.lang.Double.parseDouble(Double.java:538)
    at javaxmlparseandshow.ParseTheXml.getCurrencyList(ParseTheXml.java:55)
    at javaxmlparseandshow.ParseTheXml.main(ParseTheXml.java:75)

有人可以帮我解决这些问题吗？预先感谢。

Answer 1

据错误堆栈跟踪显示， element.getElementsByTagName（“ ForexSelling”）字段没有数据。解析器尝试将空数据转换为字符串并引发错误。查看xml，您必须看到空白字段。作为解决方案，我认为您需要首先检查数据是否为空：

Answer 2

您尝试了以下方法吗

String forexStr = element.getElementsByTagName("ForexSelling").item(0).getTextContent();
if( /* forexStr conforms to your criteria like, for example: !forexStr.equals("")*/){
    currencyPojoObject.setForexSelling(Double.parseDouble(forexStr); 
}

？

Answer 3

或者，您可以将0设置为空xml字符串

private double parseDouble(String val){
    if(val== null || val.isEmpty()) 
        return 0.0;
    else
        return Double.parseDouble(val);
}

EX：

currencyPojoObject.setForexSelling(parseDouble(element.getElementsByTagName("ForexSelling").item(0).getTextContent()));

Java.lang.NumberFormatException错误：空字符串-汇率应用程序

3 个答案: