Android java.lang.IllegalArgumentException：主机名不能为空
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java.lang.IllegalArgumentException: Host name may not be null
提问by user3622530
Hello everyone I'm posting here my question bcz i've gone through all the post , but didn't get any help for my problem. I'm using jersey web service and trying to access through android phone via URL .I want to print hello message from web service but it always throws java.lang.IllegalArgumentException Host name may not be null, added internet permission,
please check my activity
大家好，我在这里发布了我的问题，因为我已经浏览了所有帖子，但没有为我的问题提供任何帮助。我正在使用 jersey Web 服务并尝试通过 URL 通过 android 手机访问。我想从 Web 服务打印 hello 消息，但它总是抛出 java.lang.IllegalArgumentException Host name may not be null，添加了互联网权限，请检查我的活动
public class MainActivity extends Activity {
公共类 MainActivity 扩展 Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
EditText content = (EditText)this.findViewById(R.id.editText1);
// Creating HTTP client
HttpClient httpClient = new DefaultHttpClient();
// Creating HTTP Post
HttpGet httpget = new HttpGet("http://localhost:10.0.2.2:8009/BookService/rest/bookresource/hello");
HttpResponse res;
try {
res = httpClient.execute(httpget);
BufferedReader br = null;
StringBuilder sb = new StringBuilder();
String line;
br = new BufferedReader(new InputStreamReader(res.getEntity().getContent()));
while ((line = br.readLine()) != null) {
sb.append(line);
}
content.setText(sb);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
here is logcat output
这是 logcat 输出
05-10 01:38:24.768: D/AndroidRuntime(1438): Shutting down VM
05-10 01:38:24.768: W/dalvikvm(1438): threadid=1: thread exiting with uncaught exception (group=0xb4b0cba8)
05-10 01:38:24.818: E/AndroidRuntime(1438): FATAL EXCEPTION: main
05-10 01:38:24.818: E/AndroidRuntime(1438): Process: com.example.androidhttp, PID: 1438
05-10 01:38:24.818: E/AndroidRuntime(1438): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.androidhttp/com.example.androidhttp.MainActivity}: **java.lang.IllegalArgumentException: Host name may not be null**
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread.access0(ActivityThread.java:135)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.os.Handler.dispatchMessage(Handler.java:102)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.os.Looper.loop(Looper.java:136)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-10 01:38:24.818: E/AndroidRuntime(1438): at java.lang.reflect.Method.invokeNative(Native Method)
05-10 01:38:24.818: E/AndroidRuntime(1438): at java.lang.reflect.Method.invoke(Method.java:515)
05-10 01:38:24.818: E/AndroidRuntime(1438): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-10 01:38:24.818: E/AndroidRuntime(1438): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-10 01:38:24.818: E/AndroidRuntime(1438): at dalvik.system.NativeStart.main(Native Method)
05-10 01:38:24.818: E/AndroidRuntime(1438): Caused by: java.lang.IllegalArgumentException: Host name may not be null
05-10 01:38:24.818: E/AndroidRuntime(1438): at org.apache.http.HttpHost.<init>(HttpHost.java:83)
05-10 01:38:24.818: E/AndroidRuntime(1438): at org.apache.http.impl.client.AbstractHttpClient.determineTarget(AbstractHttpClient.java:497)
05-10 01:38:24.818: E/AndroidRuntime(1438): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
05-10 01:38:24.818: E/AndroidRuntime(1438): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
05-10 01:38:24.818: E/AndroidRuntime(1438): at com.example.androidhttp.MainActivity.onCreate(MainActivity.java:59)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.Activity.performCreate(Activity.java:5231)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-10 01:38:24.818: E/AndroidRuntime(1438): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
05-10 01:38:24.818: E/AndroidRuntime(1438): ... 11 more
回答by Gary Schreiner
HttpGet httpget = new HttpGet("http://localhost:10.0.2.2:8009/BookService/rest/bookresource/hello");
the host of your URL is http://localhost:10.0.2.2:8009/and is therefore invalid .. change it to either http://localhost:8009/, or http://10.0.2.2:8009/and that should fix it. The bad URL is likely causing an Exception in the HttpGet where it processes the URL is returning a null to the rest of the code
您的 URL 的主机是http://localhost:10.0.2.2:8009/，因此无效.. 将其更改为http://localhost:8009/, orhttp://10.0.2.2:8009/并且应该修复它。错误的 URL 可能导致 HttpGet 中的异常，它在处理 URL 时向其余代码返回空值
回答by Piyush
Here your URL is
你的网址在这里
HttpGet httpget = new HttpGet("http://localhost:10.0.2.2:8009/BookService/rest/bookresource/hello");
Means you are using local web service. So you have to run your application in Emulatorinstead of android phone device. So you need to change it to either http://localhost:8009/, or http://10.0.2.2:8009/
表示您正在使用本地 Web 服务。所以你必须在Emulator而不是android phone device. 因此，您需要将其更改为http://localhost:8009/, 或http://10.0.2.2:8009/
