Java 尝试解析XML时出错

我的XMLParser有一些问题，它在应用程序打开前崩溃。我得到的错误是：

错误：

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

这是我的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));
    }

}

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

在我的主要活动中，我这样称呼它：

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));
    }

}

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

---

因此，如果您能帮助我，是什么导致了这些问题。

stacktrace告诉您到底出了什么问题：您不应该在UI线程上执行网络操作

好的解决方法：不要在UI线程上做网络工作，使用AsyncTask或其他

快速修复：在网络内容之前添加以下内容：

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

---

请参见

您是否获得了一个

android.os.NetworkOnMainThreadException

？不能在主活动线程上调用网络API（即

httpClient.execute（）

）。相反，您需要在

异步任务中运行它。如果需要有关如何完成此操作的帮助，请单击。
请将整个堆栈跟踪发布到以下位置：