我正在尝试使用jsoup编写一个刮天气的android应用程序。我有在Java中工作的代码,但是即使是我可以在android中编写的最简单的形式,也会引发错误。这是我的代码的一部分:
private class Retrieve_Weather extends AsyncTask<Void, Void, String> {
private final String TAG = "Retrieve_Weather";
protected String doInBackground(Void... params) {
String weatherline= "oTHErly";
Log.i(TAG, weatherline);
Document doc = null;
try {
Log.i(TAG, "trying document...");
doc = Jsoup.connect("http://m.wund.com/cgi-bin/findweather/getForecast?brand=mobile&query=02139").get();
Log.i(TAG, "after document");
weatherline = "newline";
}
catch (IOException except) {
Log.i(TAG, "Cannot Connect", except);
except.printStackTrace();
weatherline = "Can't Connect";
Log.i(TAG, "End stacktrace");
}
Log.i(TAG, weatherline);
return weatherline;
}
@Override
protected void onPreExecute() {
Log.i(TAG, "onPreExecute");
}
@Override
protected void onProgressUpdate(Void... values) {
Log.i(TAG, "onProgressUpdate");
}
@Override
protected void onPostExecute(String result){
//super.onPostExecute(result);
Log.i(TAG, "onPostExecute");
}
}
我已经玩弄了我的代码和logcat,足以弄清楚我的错误是运行.get()时抛出的nullpointerexception异常。我只是不知道为什么或如何解决它。这是我的堆栈跟踪:
07-09 03:18:13.901: I/Retrieve_Weather(1754): trying document...
07-09 03:18:15.900: D/dalvikvm(1754): GC_CONCURRENT freed 80K, 7% free 2711K/2912K, paused 83ms+20ms, total 244ms
07-09 03:18:15.910: D/dalvikvm(1754): WAIT_FOR_CONCURRENT_GC blocked 157ms
07-09 03:18:16.351: D/dalvikvm(1754): GC_CONCURRENT freed 297K, 15% free 2841K/3340K, paused 81ms+124ms, total 329ms
07-09 03:18:16.740: W/dalvikvm(1754): Exception Ljava/lang/NullPointerException; thrown while initializing Lorg/jsoup/nodes/Entities;
07-09 03:18:16.740: W/dalvikvm(1754): Exception Ljava/lang/ExceptionInInitializerError; thrown while initializing Lorg/jsoup/nodes/Entities$EscapeMode;
07-09 03:18:16.810: W/System.err(1754): java.util.concurrent.ExecutionException: java.lang.ExceptionInInitializerError
07-09 03:18:16.830: W/System.err(1754): at java.util.concurrent.FutureTask.report(FutureTask.java:94)
07-09 03:18:16.830: W/System.err(1754): at java.util.concurrent.FutureTask.get(FutureTask.java:160)
07-09 03:18:16.860: W/System.err(1754): at android.os.AsyncTask.get(AsyncTask.java:482)
07-09 03:18:16.880: W/System.err(1754): at com.example.weatherresponse.Weather.onCreate(Weather.java:35)
07-09 03:18:16.880: W/System.err(1754): at android.app.Activity.performCreate(Activity.java:5104)
07-09 03:18:16.911: W/System.err(1754): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
07-09 03:18:16.911: W/System.err(1754): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
07-09 03:18:16.960: W/System.err(1754): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
07-09 03:18:16.970: W/System.err(1754): at android.app.ActivityThread.access$600(ActivityThread.java:141)
07-09 03:18:16.970: W/System.err(1754): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
07-09 03:18:16.980: W/System.err(1754): at android.os.Handler.dispatchMessage(Handler.java:99)
07-09 03:18:16.990: W/System.err(1754): at android.os.Looper.loop(Looper.java:137)
07-09 03:18:16.990: W/System.err(1754): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-09 03:18:16.990: W/System.err(1754): at java.lang.reflect.Method.invokeNative(Native Method)
07-09 03:18:17.010: W/System.err(1754): at java.lang.reflect.Method.invoke(Method.java:511)
07-09 03:18:17.061: W/System.err(1754): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-09 03:18:17.061: W/System.err(1754): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-09 03:18:17.061: W/System.err(1754): at dalvik.system.NativeStart.main(Native Method)
07-09 03:18:17.090: W/System.err(1754): Caused by: java.lang.ExceptionInInitializerError
07-09 03:18:17.090: W/System.err(1754): at org.jsoup.nodes.Document$OutputSettings.<init>(Document.java:210)
07-09 03:18:17.150: W/dalvikvm(1754): threadid=11: thread exiting with uncaught exception (group=0x40a71930)
07-09 03:18:17.150: W/System.err(1754): at org.jsoup.nodes.Document.<init>(Document.java:18)
07-09 03:18:17.160: W/System.err(1754): at org.jsoup.parser.TreeBuilder.initialiseParse(TreeBuilder.java:27)
07-09 03:18:17.160: W/System.err(1754): at org.jsoup.parser.TreeBuilder.parse(TreeBuilder.java:40)
07-09 03:18:17.160: W/System.err(1754): at org.jsoup.parser.HtmlTreeBuilder.parse(HtmlTreeBuilder.java:37)
07-09 03:18:17.170: W/System.err(1754): at org.jsoup.parser.Parser.parseInput(Parser.java:30)
07-09 03:18:17.170: W/System.err(1754): at org.jsoup.helper.DataUtil.parseByteData(DataUtil.java:102)
07-09 03:18:17.170: W/System.err(1754): at org.jsoup.helper.HttpConnection$Response.parse(HttpConnection.java:498)
07-09 03:18:17.215: W/System.err(1754): at org.jsoup.helper.HttpConnection.get(HttpConnection.java:154)
07-09 03:18:17.215: W/System.err(1754): at com.example.weatherresponse.Weather$Retrieve_Weather.doInBackground(Weather.java:85)
07-09 03:18:17.220: W/System.err(1754): at com.example.weatherresponse.Weather$Retrieve_Weather.doInBackground(Weather.java:1)
07-09 03:18:17.220: W/System.err(1754): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-09 03:18:17.230: W/System.err(1754): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
07-09 03:18:17.230: W/System.err(1754): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-09 03:18:17.240: W/System.err(1754): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-09 03:18:17.240: W/System.err(1754): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-09 03:18:17.240: W/System.err(1754): at java.lang.Thread.run(Thread.java:856)
07-09 03:18:17.260: W/System.err(1754): Caused by: java.lang.ExceptionInInitializerError
07-09 03:18:17.290: W/System.err(1754): at org.jsoup.nodes.Entities$EscapeMode.<clinit>(Entities.java:20)
07-09 03:18:17.290: W/System.err(1754): ... 17 more
07-09 03:18:17.290: W/System.err(1754): Caused by: java.lang.NullPointerException: in == null
07-09 03:18:17.290: W/System.err(1754): at java.util.Properties.load(Properties.java:246)
07-09 03:18:17.290: W/System.err(1754): at org.jsoup.nodes.Entities.loadEntities(Entities.java:151)
07-09 03:18:17.290: W/System.err(1754): at org.jsoup.nodes.Entities.<clinit>(Entities.java:135)
07-09 03:18:17.290: W/System.err(1754): ... 18 more
07-09 03:18:17.383: I/System.out(1754): ExecExceptjava.lang.ExceptionInInitializerError
07-09 03:18:19.570: E/AndroidRuntime(1754): FATAL EXCEPTION: AsyncTask #1
07-09 03:18:19.570: E/AndroidRuntime(1754): java.lang.RuntimeException: An error occured while executing doInBackground()
07-09 03:18:19.570: E/AndroidRuntime(1754): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
07-09 03:18:19.570: E/AndroidRuntime(1754): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.lang.Thread.run(Thread.java:856)
07-09 03:18:19.570: E/AndroidRuntime(1754): Caused by: java.lang.ExceptionInInitializerError
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.nodes.Document$OutputSettings.<init>(Document.java:210)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.nodes.Document.<init>(Document.java:18)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.parser.TreeBuilder.initialiseParse(TreeBuilder.java:27)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.parser.TreeBuilder.parse(TreeBuilder.java:40)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.parser.HtmlTreeBuilder.parse(HtmlTreeBuilder.java:37)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.parser.Parser.parseInput(Parser.java:30)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.helper.DataUtil.parseByteData(DataUtil.java:102)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.helper.HttpConnection$Response.parse(HttpConnection.java:498)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.helper.HttpConnection.get(HttpConnection.java:154)
07-09 03:18:19.570: E/AndroidRuntime(1754): at com.example.weatherresponse.Weather$Retrieve_Weather.doInBackground(Weather.java:85)
07-09 03:18:19.570: E/AndroidRuntime(1754): at com.example.weatherresponse.Weather$Retrieve_Weather.doInBackground(Weather.java:1)
07-09 03:18:19.570: E/AndroidRuntime(1754): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
07-09 03:18:19.570: E/AndroidRuntime(1754): ... 4 more
07-09 03:18:19.570: E/AndroidRuntime(1754): Caused by: java.lang.ExceptionInInitializerError
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.nodes.Entities$EscapeMode.<clinit>(Entities.java:20)
07-09 03:18:19.570: E/AndroidRuntime(1754): ... 17 more
07-09 03:18:19.570: E/AndroidRuntime(1754): Caused by: java.lang.NullPointerException: in == null
07-09 03:18:19.570: E/AndroidRuntime(1754): at java.util.Properties.load(Properties.java:246)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.nodes.Entities.loadEntities(Entities.java:151)
07-09 03:18:19.570: E/AndroidRuntime(1754): at org.jsoup.nodes.Entities.<clinit>(Entities.java:135)
07-09 03:18:19.570: E/AndroidRuntime(1754): ... 18 more
除了这一行基本代码外,我的代码都能正常运行。我已经在模拟器和Android手机上测试了我的代码,并且都可以访问互联网。我试过多个网站,以及这些网站的移动版本,但没有一个起作用。我的清单和库文件都在正确的位置具有Internet权限。我在这个站点和其他站点上到处都是关于我的问题的解决方案。由于我在相关帖子中找到了我所修改的代码和权限,但是我还没有找到适合我的已回答帖子。但是,我发现了一些未回答的帖子,它们提出了完全相同的问题。我发现我尚未尝试过的唯一答案是此问题使用AsyncTask和Jsoup释放APK时出错:我不知道要更改哪个文件来测试它是否解决了我的问题。我是编程的新手,将不胜感激。谢谢!
我的代码现在可以使用了!我最终将.jar文件移动到lib中,而不是按照Android-SDK r17的建议将其用作引用的外部jar破坏了工作项目。我还添加了一个用户代理,并对AsyncTask进行了重新设计,以便Jsoup.connect(url)位于onPreExecute中,而将.get()保留在doInBackground中。
private class Retrieve_Weather extends AsyncTask<Void, Void, String> {
private final String TAG = "Retrieve_Weather";
Connection con = null;
protected Void doInBackground(String... params) {
//Log.i(TAG, weatherline);
Document doc = null;
if (con !=null){
try {
Log.i(TAG, "trying document...");
doc = con.get();
Log.i(TAG, "after document");
Element currentWeather = doc.getElementById("curCond");
currentweather = currentWeather.text();
Log.i(TAG, currentWeather.text());
}
catch (IOException except) {
Log.i(TAG, "Cannot Connect", except);
except.printStackTrace();
currentweather = "Can't Connect";
Log.i(TAG, "End stacktrace");
}
}
else{
currentweather = "Connection returned null";
}
//Log.i(TAG, weatherline);
return currentweather;
}
@Override
protected void onPreExecute() {
//Log.i(TAG, "onPreExecute");
Log.i(TAG, "trying to connect...");
con = Jsoup.connect("http://www.wunderground.com/cgi-bin/findweather/getForecast?query=zmw:02142.1.99999").userAgent("Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20100101 Firefox/21.0");
Log.i(TAG, "CONNECTED!!!");
}
@Override
protected void onProgressUpdate(Void... values) {
Log.i(TAG, "onProgressUpdate");
}
@Override
protected void onPostExecute(Void result){
Log.i(TAG, "onPostExecute");
}
}
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