发送http网址请求

时间：2014-02-05 02:14:55

标签： java android http

我一直在尝试将Android开发者页面中的HttpURLConnection片段复制到我的项目中，看看我是否可以建立互联网连接，每次运行我的应用程序关闭的功能。我不确定为什么申请失败，任何帮助将不胜感激。此代码放在public class main extends Activity

中

main.java：

public void showHelp() throws IOException {
        URL url = new URL("http://www.android.com/");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        try{
            InputStream in = new BufferedInputStream(urlConnection.getInputStream());
            //readStream(in);
        } finally{
            urlConnection.disconnect();
        }
    }

我注释掉了readStream因为我认为转换可能是问题，但事实并非如此。功能是：

private String readStream(InputStream is) {
        try {
          ByteArrayOutputStream bo = new ByteArrayOutputStream();
          int i = is.read();
          while(i != -1) {
            bo.write(i);
            i = is.read();
          }
          return bo.toString();
        } catch (IOException e) {
          return "";
        }
    }

如果发布日志猫结果有帮助请告诉我。我在Android编程方面相当新，当点击一个菜单选项时，第一个函数被调用，但我不认为这是相关的。还

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

包含在android清单xml

中

logcat错误：

02-04 21:27:14.468: W/dalvikvm(16978): threadid=1: thread exiting with uncaught exception (group=0x4208d2a0)
02-04 21:27:14.492: E/AndroidRuntime(16978): FATAL EXCEPTION: main
02-04 21:27:14.492: E/AndroidRuntime(16978): android.os.NetworkOnMainThreadException
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at java.net.InetAddress.getAllByName(InetAddress.java:214)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpEngine.connect(HttpEngine.java:310)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.MeadowEast.audiotest.MainActivity.showHelp(MainActivity.java:369)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.MeadowEast.audiotest.MainActivity.onOptionsItemSelected(MainActivity.java:97)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.app.Activity.onMenuItemSelected(Activity.java:2625)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:1061)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:179)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.widget.AdapterView.performItemClick(AdapterView.java:298)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.widget.AbsListView.performItemClick(AbsListView.java:1280)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3083)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.widget.AbsListView$1.run(AbsListView.java:3983)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.os.Handler.handleCallback(Handler.java:615)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.os.Handler.dispatchMessage(Handler.java:92)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.os.Looper.loop(Looper.java:137)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at android.app.ActivityThread.main(ActivityThread.java:4949)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at java.lang.reflect.Method.invokeNative(Native Method)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at java.lang.reflect.Method.invoke(Method.java:511)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1043)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
02-04 21:27:14.492: E/AndroidRuntime(16978):    at dalvik.system.NativeStart.main(Native Method)

新的AsyncTask代码：

private abstract class myTask extends AsyncTask<String,Void,Void>{
        protected void doInBackground(String addressName) throws IOException {
            URL url = new URL(addressName);
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            try{
                InputStream in = new BufferedInputStream(urlConnection.getInputStream());
                //readStream(in);
            } finally{
                urlConnection.disconnect();
            }
         }

         protected void onProgressUpdate() {
             //do nothing
         }

         protected void onPostExecute() {
             //toast me
         }
    }

来自：

 public void showHelp(){
        new myTask().execute("http://www.android.com/");
    }

我无法加载到Android设备我遇到问题：无法实例化类型main.mytask

3 个答案:

答案 0 :(得分：0)

我能想到的一个原因是您将网络通信放在主线程上。你不被允许这样做。您可以使用AsyncTask 

http://developer.android.com/reference/android/os/AsyncTask.html

对于测试，您可以在主要活动中添加以下内容，但这是不好的做法。

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

答案 1 :(得分：0)

您需要在不同的线程中进行网络操作

答案 2 :(得分：0)

查看你的logcat，你的问题是NetworkOnMainThreadException，以便将你的urlconnection放入其他线程

new Thread(new Runnable() {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        showHelp();
    }
}).start();
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