当解析 XML 时出现的错误

Question

在应用程序打开之前 XMLParser 就崩溃了。错误是：

org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)

XMLParser 代码：

public class XMLParser {
    public XMLParser(){
    }
    public String getXmlFromUrl(String url){
        String xml = null;
        try{
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            xml = EntityUtils.toString(httpEntity);
        } catch (UnsupportedEncodingException e){
            e.printStackTrace();
        } catch (ClientProtocolException e){
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return xml;
    }
    public Document getDomElement(String xml){
        Document doc = null;
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try{
            DocumentBuilder db = dbf.newDocumentBuilder();

            InputSource is = new InputSource();
            is.setCharacterStream(new StringReader(xml));
            doc = db.parse(is);
        } catch(ParserConfigurationException e) {
            Log.e("Error: ", e.getMessage());
            return null;
        } catch (SAXException e) {
            Log.e("Error: ", e.getMessage());
            return null;
        } catch (IOException e) {
            Log.e("Error: ", e.getMessage());
            return null;
        }
        return doc;
    }
    public final String getElementValue(Node elem) {
        Node child;

        if(elem != null){
            if(elem.hasChildNodes()){
                for(child = elem.getFirstChild(); child != null; child = child.getNextSibling()){
                    if(child.getNodeType() == Node.TEXT_NODE){
                        return child.getNodeValue();
                    }
                }
            }
        }
        return "";
    }
    public String getValue(Element item, String str){
        NodeList n = item.getElementsByTagName(str);
        return this.getElementValue(n.item(0));
    }
}

在 main activity 中是这样调用的：

XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(URL);
Document doc = parser.getDomElement(xml);

所以问题出在哪里呢？

Answer 1

添加：

 StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
 StrictMode.setThreadPolicy(policy);