我一直在研究一个Android项目,我想要一些API来获取信息.看起来这应该是非常基本的！

这是我的代码的一般要点：

private InputStream retrieveStream2(String url)

{

DefaultHttpClient client = new DefaultHttpClient();

HttpGet getRequest = new HttpGet(url);

System.out.println("getRequest == " + getRequest);

try {

HttpResponse getResponse = client.execute(getRequest);//here is teh problem

final int statusCode = getResponse.getStatusLine().getStatusCode();

if (statusCode != HttpStatus.SC_OK)

{

Log.w(getClass().getSimpleName(),

"Error " + statusCode + " for URL " + url);

return null;

}

HttpEntity getResponseEntity = getResponse.getEntity();

return getResponseEntity.getContent();

}

catch (Exception e)

{

getRequest.abort();

Log.w(getClass().getSimpleName(), "Error for URL, YO " + url, e);

}

return null;

}

其中url变量是字符串“http://search.twitter.com/search.json?q=javacodegeeks”.

正如您所看到的,该站点有一些不错的JSON信息;我的问题是,每次调用’client.execute(getRequest);”时,程序都会抛出并捕获异常.没用处！

我听说过两件事：

1)您必须为模拟器/设备设置使用互联网的权限！

?? – 我想我已经覆盖了这个,但也许我做错了！

??在我添加的androidmanifest.xml中

< uses-permission android:name="android.permission.INTERNET" >< /uses-permission>

就是这样.

2)(我不太确定)你不能在’ui’线程中启动’网络’线程.我不完全确定这意味着什么,但我继续前进并遵循Android Threads,Handlers和AsyncTasks的一些教程.这里：请查看我遵循的AsyncTask教程下的代码：

继AsyncTask教程之后,我发现我仍然遇到同样的问题 –

这条线：

HttpGet httpGet = new HttpGet(url)

像往常一样抛出异常.

这是我尝试上面的线程教程的logcat：

02-27 20:43:28.565: I/ActivityManager(92): START {cmp=com.Prometheus.R1/.JsonParsingActivity} from pid 574

02-27 20:43:28.565: W/WindowManager(92): Failure taking screenshot for (180x300) to layer 21010

02-27 20:43:28.896: I/System.out(574): pre execute

02-27 20:43:29.236: I/ActivityManager(92): Displayed com.Prometheus.R1/.JsonParsingActivity: +638ms

02-27 20:43:29.329: I/ARMAssembler(35): generated scanline__00000077:03010104_00008001_00000000 [ 89 ipp] (110 ins) at [0x40fad6a8:0x40fad860] in 7204915 ns

02-27 20:43:30.016: W/System.err(574): java.net.UnknownHostException: Unable to resolve host "search.twitter.com": No address associated with hostname

02-27 20:43:30.016: W/System.err(574): at java.net.InetAddress.lookupHostByName(InetAddress.java:426)

02-27 20:43:30.026: W/System.err(574): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)

02-27 20:43:30.026: W/System.err(574): at java.net.InetAddress.getAllByName(InetAddress.java:220)

02-27 20:43:30.026: W/System.err(574): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)

02-27 20:43:30.036: W/System.err(574): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)

02-27 20:43:30.036: W/System.err(574): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)

02-27 20:43:30.046: W/System.err(574): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)

02-27 20:43:30.046: W/System.err(574): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)

02-27 20:43:30.046: W/System.err(574): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)

02-27 20:43:30.055: W/System.err(574): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)

02-27 20:43:30.055: W/System.err(574): at com.Prometheus.R1.JsonParsingActivity$DownloadWebPageTask.doInBackground(JsonParsingActivity.java:88)

02-27 20:43:30.055: W/System.err(574): at com.Prometheus.R1.JsonParsingActivity$DownloadWebPageTask.doInBackground(JsonParsingActivity.java:1)

02-27 20:43:30.055: W/System.err(574): at android.os.AsyncTask$2.call(AsyncTask.java:264)

02-27 20:43:30.066: W/System.err(574): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)

02-27 20:43:30.066: W/System.err(574): at java.util.concurrent.FutureTask.run(FutureTask.java:137)

02-27 20:43:30.066: W/System.err(574): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)

02-27 20:43:30.076: W/System.err(574): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)

02-27 20:43:30.076: W/System.err(574): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)

02-27 20:43:30.087: W/System.err(574): at java.lang.Thread.run(Thread.java:856)

02-27 20:43:30.108: W/System.err(574): Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)

02-27 20:43:30.116: W/System.err(574): at libcore.io.Posix.getaddrinfo(Native Method)

02-27 20:43:30.116: W/System.err(574): at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55)

02-27 20:43:30.126: W/System.err(574): at java.net.InetAddress.lookupHostByName(InetAddress.java:411)

02-27 20:43:30.126: W/System.err(574): ... 18 more

02-27 20:43:30.136: I/System.out(574): Except thrown by url http://search.twitter.com/search.json?q=javacodegeeks, ....

02-27 20:43:30.136: I/System.out(574): response =

您可以看到异常是UnknownHostException：

“ava.net.UnknownHostException：无法解析主机”search.twitter.com“：没有与主机名关联的地址”

但我不认为该网站是不可接受的……

任何人都可以告诉我,我需要做些什么才能通过它？