XML 解析器返回意外的令牌错误和空指针异常

XML Parser Returning unexpected token error and null pointer exception(XML 解析器返回意外的令牌错误和空指针异常)

问题描述

所以我认为我在以前的帖子中质疑了错误的方式.我最好这样说.我正在尝试解析 XML 数据:

So I think I was questioning the wrong way in previous threads. I better put it like this. I'm trying to parse the XML data:

<playlist>
<title>![CDATA[New Playlist]]</title>
<items>
<item>
<title>HAMD(LA ILAHA ILLALLAH)</title>
<description>Recited By :Alhaaj Muhammad Owais Raza Qadri -- Written By: Mufti-e-Azam Hind Molana Mustafa Raza Khan Noori</description>
<image>http://xxx.xxx.xxx.xxx/~kanz/video/Images/9.jpg</image>
<startFromThis>true</startFromThis>
<duration>510</duration>
<source>http://xxx.xxx.xxx.xxx/~kanz/video/flv/9.flv</source>
<sourceAlt>http://xxx.xxx.xxx.xxx/~kanz/video/mp4/9.mp4</sourceAlt>
<sourceType>direct</sourceType>
</item>
</items>
</playlist>

在我的活动中，我所做的是这样，但 logcat 给出了空指针异常.这是我的活动，下面是 logcat 错误.

In my Activity, what I did was this but the logcat gives null pointer exception. Here's my Activity and below it the logcat error.

static final String URL = "http://xxx.xxx.xxx.xxx/~kanz/video/XML/9.xml";

// XML node keyse.
static final String KEY_SONG = "item"; // parent node
static final String KEY_TITLE = "title";
static final String KEY_ARTIST = "description";
static final String KEY_THUMB_URL = "image";
static final String KEY_DURATION = "duration";

NodeList nl = doc.getElementsByTagName(KEY_SONG);

// looping through all song nodes <song>
for (int i = 0; i < nl.getLength(); i++) {
    // creating new HashMap
    HashMap<String, String> map = new HashMap <String, String>();
    Element e = (Element) nl.item(i);
    // adding each child node to HashMap key => value
    map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE));
    map.put(KEY_ARTIST, parser.getValue(e, KEY_ARTIST));
    map.put(KEY_THUMB_URL, parser.getValue(e, KEY_THUMB_URL));
    map.put(KEY_DURATION, parser.getValue(e, KEY_DURATION));

    // adding HashList to ArrayList
    songsList.add(map);
}

Logcat 给出 Unexpected Token 错误并返回 null 导致空指针异常.

Logcat gives Unexpected Token error and returns null which causes null pointer exception.

03-28 14:31:34.059: E/Error:(895): Unexpected token (position:TEXT @1:4 in java.io.StringReader@40d220e0) 
03-28 14:31:34.080: I/System.out(895): null
03-28 14:42:59.560: D/AndroidRuntime(978): Shutting down VM
03-28 14:42:59.560: W/dalvikvm(978): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
03-28 14:42:59.639: E/AndroidRuntime(978): FATAL EXCEPTION: main
03-28 14:42:59.639: E/AndroidRuntime(978): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.razatubevidurl/com.example.razatubevidurl.CustomizedListView}: java.lang.NullPointerException
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.os.Handler.dispatchMessage(Handler.java:99)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.os.Looper.loop(Looper.java:137)
03-28 14:42:59.639: E/AndroidRuntime(978):  at android.app.ActivityThread.main(ActivityThread.java:5041)
03-28 14:42:59.639: E/AndroidRuntime(978):  at java.lang.reflect.Method.invokeNative(Native Method)
03-28 14:42:59.639: E/AndroidRuntime(978):  at java.lang.reflect.Method.invoke(Method.java:511)
03-28 14:42:59.639: E/AndroidRuntime(978):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-28 14:42:59.639: E/AndroidRuntime(978):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-28 14:42:59.639: E/AndroidRuntime(978):  at dalvik.system.NativeStart.main(Native Method)
03-28 14:42:59.639: E/AndroidRuntime(978): Caused by: java.lang.NullPointerException

请告诉我我做错了什么.我认为我之前的问题含糊不清，在这一个问题中，我尽力使问题清晰易懂.

Please tell me what I'm doing wrong. I thought my previous question was vague and in this one, I tried my best to make the question clear and understandable.

推荐答案

我猜这和编码有关.也许您的解析器不喜欢感叹号 (!).您能否确保使用正确编码的 XML 文件?(UTF-8)

I guess it's something about encoding. Maybe your parser doesn't like the exclamation mark (!). Can you make sure that you use the XML file with the correct encoding? (UTF-8)

否则，你有这个问题:KXmlParser 抛出意外的令牌"；RSS 开始时的异常.

Otherwise, you have this problem: KXmlParser throws "Unexpected token" exception at the start of RSS pasing.

我搜索了一下，看起来最简单的解决方法是 这里.您可以尝试添加此方法.(根据您使用的教程，将其放在 ImageLoader 类中.)

I googled around and it looks like the easiest fix is here. You can try adding this method. (From the tutorial you use, put this in the ImageLoader class.)

import java.io.PushbackInputStream;
private InputStream checkForUtf8BOMAndDiscardIfAny(InputStream inputStream) throws IOException {
PushbackInputStream pushbackInputStream = new PushbackInputStream(new BufferedInputStream(inputStream), 3);
byte[] bom = new byte[3];
if (pushbackInputStream.read(bom) != -1) {
    if (!(bom[0] == (byte) 0xEF && bom[1] == (byte) 0xBB && bom[2] == (byte) 0xBF)) {
        pushbackInputStream.unread(bom);
    }
}
return pushbackInputStream; }

那你就可以了

InputStream is=conn.getInputStream();
is = checkForUtf8BOMAndDiscardIfAny(is);

我没有机会测试该方法，但它应该这样做.另外，请参阅 字节顺序标记搞砸了 Java 中的文件读取.

I don't have a chance to test the method but it should do it. Also, please see Byte order mark screws up file reading in Java.

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