java - 在 java MalformedurException 中解析 XML

Question

我正在尝试解析 xml 文件，但发生了 Malformedurlexception。您知道为什么会发生这种情况吗？

注意:在第一个代码段中有一行注释 system.out.println(requestXml) 它正在工作(xml 内容以字符串形式出现)，但我想解析它，但是解析方法不起作用。

代码

String requestXml = "";

try {
    String argUrl = "http://192.168.1.25:3480/data_request?id=sdata&output_format=xml";

    URL url = new URL(argUrl);
    URLConnection con = url.openConnection();
    // specify that we will send output and accept input
    con.setDoInput(true);
    con.setDoOutput(true);

    con.setConnectTimeout(20000);  // long timeout, but not infinite
    con.setReadTimeout(20000);

    con.setUseCaches(false);
    con.setDefaultUseCaches(false);

    // tell the web server what we are sending
    con.setRequestProperty("Content-Type", "text/xml");

    OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());
    writer.write(requestXml);
    writer.flush();
    writer.close();

    // reading the response
    InputStreamReader reader = new InputStreamReader(con.getInputStream());

    StringBuilder buf = new StringBuilder();
    char[] cbuf = new char[2048];
    int num;

    while (-1 != (num = reader.read(cbuf))) {
        buf.append(cbuf, 0, num);
    }
    requestXml = buf.toString();
    xmlParser(requestXml);

    //System.out.println(requestXml);

} catch (Throwable t) {
    t.printStackTrace(System.out);
}
return requestXml;

而 xmlParser 方法是:

protected void xmlParser(String xmlToBeParsed) {

    try {

        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(xmlToBeParsed);
        doc.getDocumentElement().normalize();
        NodeList nodes = doc.getElementsByTagName("devices");

        for (int i = 0; i < nodes.getLength(); i++) {
            Node node = nodes.item(i);

            if (node.getNodeType() == Node.ELEMENT_NODE) {
                Element element = (Element) node;
                System.out.println("Stock Symbol: " + getValue("device name", element));

            }
        }

    } catch (ParserConfigurationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SAXException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

private static String getValue(String tag, Element element) {
    NodeList nodes = element.getElementsByTagName(tag).item(0).getChildNodes();
    Node node = (Node) nodes.item(0);
    return node.getNodeValue();
}  

日志是:

04-30 11:55:21.299: W/System.err(826): java.net.MalformedURLException: Protocol not found: 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.299: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): 04-30 11:55:21.309: W/System.err(826): at java.net.URL.(URL.java:178) 04-30 11:55:21.309: W/System.err(826): at java.net.URL.(URL.java:127) 04-30 11:55:21.309: W/System.err(826): at org.apache.harmony.xml.parsers.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:115) 04-30 11:55:21.319: W/System.err(826): at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:155) 04-30 11:55:21.319: W/System.err(826): at com.example.eos.SensorDataConnector.xmlParser(SensorDataConnector.java:93) 04-30 11:55:21.319: W/System.err(826): at com.example.eos.SensorDataConnector.getXMLData(SensorDataConnector.java:71) 04-30 11:55:21.319: W/System.err(826): at com.example.eos.EnergyOptimizer$5.onClick(EnergyOptimizer.java:148) 04-30 11:55:21.319: W/System.err(826): at android.view.View.performClick(View.java:4204) 04-30 11:55:21.319: W/System.err(826): at android.view.View$PerformClick.run(View.java:17355) 04-30 11:55:21.319: W/System.err(826): at android.os.Handler.handleCallback(Handler.java:725) 04-30 11:55:21.319: W/System.err(826): at android.os.Handler.dispatchMessage(Handler.java:92) 04-30 11:55:21.319: W/System.err(826): at android.os.Looper.loop(Looper.java:137) 04-30 11:55:21.319: W/System.err(826): at android.app.ActivityThread.main(ActivityThread.java:5041) 04-30 11:55:21.319: W/System.err(826): at java.lang.reflect.Method.invokeNative(Native Method) 04-30 11:55:21.319: W/System.err(826): at java.lang.reflect.Method.invoke(Method.java:511) 04-30 11:55:21.319: W/System.err(826): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 04-30 11:55:21.319: W/System.err(826): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 04-30 11:55:21.329: W/System.err(826): at dalvik.system.NativeStart.main(Native Method)

Answer 1

您用来解析 XML 的是 this method :

public Document parse(String uri) throws SAXException, IOException

它基本上期望从中获取内容的 uri。这不是你的情况，因为你已经查询了 URL 并解析了内容。您没有提供该方法所期望的内容。

我认为如果您跳过连接输入流的所有读取并执行以下操作，应该没问题:

InputStream input = con.getInputStream();
xmlParser(input);

注意我删除了很多行。然后:

protected void xmlParser(InputStream input)
{

    try {

        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(input);