使用 InputStreamReader 解析 XML 文件时出错。意外类型: (positinon END_DOCUMENT null)

Question

各位，我是 Android 的新手，我正在尝试解析 XML 文件并获取列表中的信息。我的 XML 文件是 this，我想要的是获取对象。

我正在做的解析与 android developeres 网站上的示例类似：

import android.content.Context;
import android.util.Xml;
import android.widget.Toast;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by Álvaro on 31/08/2015.
 */
public class EntrelazadasXMLParser {
    // We don't use namespaces
    private static final String ns = null;

public List parse(InputStream in, Context context) throws /*XmlPullParserException,*/ IOException {
    try {
        XmlPullParser parser = Xml.newPullParser();
        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
        parser.setInput(in, null);
        parser.nextTag();
        return readFeed(parser,context);

    }catch (XmlPullParserException e){

        Toast.makeText(context, "Error en el parser: " + e.toString(),
                Toast.LENGTH_LONG).show();
        return null;
    }
    finally {
        in.close();
    }

}
    ....

这个steo是为了实例化一个解析器并开始解析过程。解析器在没有命名空间的情况下初始化，并使用提供的 InputStream 作为其 input.It 通过调用 nextTag() 启动解析过程并调用 readFeed() 方法，该方法提取和处理应用程序感兴趣的数据。这里是异常发生的地方，错误如下。

Error en el parser: org.xmlpull.v1.XmlPullParserException: unexpected type (position:END_DOCUMENT null@1:1 in java.io.InputStreamReader@41e3d220).

剩下的 class 是这样的：

vate List readFeed(XmlPullParser parser, Context context) throws /*XmlPullParserException,*/ IOException {
    List entries = new ArrayList();
    try {
        parser.require(XmlPullParser.START_TAG, ns, "database");
        while (parser.next() != XmlPullParser.END_TAG) {
            if (parser.getEventType() != XmlPullParser.START_TAG) {
                continue;
            }
            String name = parser.getName();
            // Starts by looking for the table tag
            if (name.equals("table")) {
                entries.add(readEntry(parser));
            } else {
                skip(parser);
            }
        }
        return entries;
    }
    catch (XmlPullParserException e){

        Toast.makeText(context, "Error en el read feed: " + e.toString(),
                Toast.LENGTH_LONG).show();
        return null;
    }
}

private void skip(XmlPullParser parser) throws XmlPullParserException, IOException {
    if (parser.getEventType() != XmlPullParser.START_TAG) {
        throw new IllegalStateException();
    }
    int depth = 1;
    while (depth != 0) {
        switch (parser.next()) {
            case XmlPullParser.END_TAG:
                depth--;
                break;
            case XmlPullParser.START_TAG:
                depth++;
                break;
        }
    }
}

private Producto readEntry(XmlPullParser parser) throws XmlPullParserException, IOException {
    parser.require(XmlPullParser.START_TAG, ns, "table");

    Producto Objeto =null;
    String summary = null;
    String link = null;

    while (parser.next() != XmlPullParser.END_TAG) {
        if (parser.getEventType() != XmlPullParser.START_TAG) {
            continue;
        }
        String name = parser.getName();
        if (name.equals("column")) {
            Objeto = readColumn(parser);
        } else {
            skip(parser);

        }
    }
    return Objeto;
}

private Producto readColumn(XmlPullParser parser) throws IOException, XmlPullParserException {
    Producto Objeto ;
    String Id = null;;
    String Referencia = null;;
    String Nombre = null;;
    String Categoria = null;;
    String SubFamilia = null;;
    String Familia = null;;
    String Descripcion = null;;
    String Precio = null;;
    String Image1 = null;
    String Image2 = null;
    String Image3 = null;
    String Image4 = null;
    String Image5 = null;
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String tag = parser.getName();
    String relType = parser.getAttributeValue(null, "name");

        if (relType.equals("Id")){
            Id = readId(parser);
        } else if(relType.equals("Precio")){
            Precio = readPrecio(parser);
        }else if(relType.equals("Referencia")){
            Referencia = readReferencia(parser);
        }else if(relType.equals("Categoria")){
            Categoria = readCategoria(parser);
        }else if(relType.equals("Nombre")){
            Nombre = readNombre(parser);
        }else if(relType.equals("Subfamilia")){
            SubFamilia = readSubfamilia(parser);
        }else if(relType.equals("Familia")){
            Familia = readFamilia(parser);
        }else if(relType.equals("Descripcion")){
            Descripcion = readDescripcion(parser);
        }else{
            Image1 = readImage(parser);
        }

    Objeto =new Producto(Id,Referencia,Nombre,Categoria,SubFamilia,Familia,Descripcion,Precio,Image1,Image2,Image3,Image4,Image5);

    parser.require(XmlPullParser.END_TAG, ns, "column");
    return Objeto;
}

// Processes Id tags in the feed.
private String readId (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readPrecio (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readReferencia (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readCategoria (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readNombre (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readSubfamilia (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readFamilia (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readDescripcion (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}

private String readImage (XmlPullParser parser) throws IOException, XmlPullParserException {
    parser.require(XmlPullParser.START_TAG, ns, "column");
    String value = readText(parser);
    parser.require(XmlPullParser.END_TAG, ns, "column");
    return value;
}
// For the tags title and summary, extracts their text values.
private String readText(XmlPullParser parser) throws IOException, XmlPullParserException {
    String result = "";
    if (parser.next() == XmlPullParser.TEXT) {
        result = parser.getText();
        parser.nextTag();
    }
    return result;
}

}

以及对解析器的调用和 inputStream 的声明：

EntrelazadasXMLParser XmlParser = new EntrelazadasXMLParser();
    List<Producto> entries = null;
    String root = Environment.getExternalStorageDirectory().toString();
    File SDCardRoot = new File(root + "/Entrelazadas");

    try {

        InputStream raw = new FileInputStream(new File(SDCardRoot, "catalogo.xml"));

        //FileInputStream fileInputStream = new FileInputStream(file);
        entries = XmlParser.parse(raw,context);

    }
    catch (FileNotFoundException e){
        Toast.makeText(context, "Fichero no encontrado: " +e.toString(),
                Toast.LENGTH_LONG).show();
    }
    catch (IOException e){
        Toast.makeText(context, "Error de IO: " +e.toString(),
                Toast.LENGTH_LONG).show();
    }

希望大家能帮帮我。非常感谢。

文件的第一行是这样的：

Answer 1

像这样迭代 while 循环直到文档结束

private void eBooksXmlParser(String xmlData, Context context) {
    XmlPullParserFactory pullParserFactory;
    ArrayList<EBook> eBooks = null;
    try {
        pullParserFactory = XmlPullParserFactory.newInstance();
        XmlPullParser parser = pullParserFactory.newPullParser();

        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
        parser.setInput(new StringReader(xmlData));

        int eventType = parser.getEventType();
        EBook currentEBook = null;

        while (eventType != XmlPullParser.END_DOCUMENT) {
            String tagName;
            switch (eventType) {
                case XmlPullParser.START_DOCUMENT:
                    break;
                case XmlPullParser.START_TAG:
                    tagName = parser.getName();
                    if (tagName.equals("wr"))
                        eBooks = new ArrayList<>();
                    else if (eBooks != null) {
                        if (tagName.equals("book")) {
                            currentEBook = new EBook();
                            currentEBook.setBookName(parser.getAttributeValue(0));
                            currentEBook.setCategory(parser.getAttributeValue(1));
                            currentEBook.setDescription(parser.getAttributeValue(2));
                            currentEBook.setFileName(parser.getAttributeValue(3));
                            currentEBook.setFormat(parser.getAttributeValue(4));
                            currentEBook.setFromDate(parser.getAttributeValue(5));
                            currentEBook.setSubCategory(parser.getAttributeValue(6));
                            currentEBook.setThumbnail(parser.getAttributeValue(7));
                            currentEBook.setTier(parser.getAttributeValue(8));
                            currentEBook.setToDate(parser.getAttributeValue(9));
                            currentEBook.setType(parser.getAttributeValue(10));
                            currentEBook.setDownloadStatus(false);
                        }
                    }
                    break;
                case XmlPullParser.END_TAG:
                    tagName = parser.getName();
                    if (tagName.equalsIgnoreCase("book")
                            && currentEBook != null) {
                        eBooks.add(currentEBook);
                        currentEBook = null;
                    }
            }
            eventType = parser.next();
        }
    } catch (XmlPullParserException | IOException e) {
        e.printStackTrace();
    }
    if (eBooks != null)
        UserDbProvider.getInstance(context).addEBooksList(
                eBooks);
}

Answer 2

问题最终出在文件上，该文件是空的，因为我在代码的其他部分有一行删除了该文件。

使用 InputStreamReader 解析 XML 文件时出错。意外类型: (positinon END_DOCUMENT null)

Error parsing a XML file with the InputStreamReader. Unexpected type: (positinon END_DOCUMENT null)

android

xml

parsing

xmlpullparser

inputstreamreader