Question

在我的应用程序中，我以JSON的形式从服务器获取数据。数据大约为1.5 MB。该应用程序可以工作，但有时它会在从服务器获取OutOfMemoryError的数据时崩溃。

这是我的方法：

private String sendPostRequest(String url, List<NameValuePair> params)
        throws Exception {
    String ret = null;

    BufferedReader bufferedReader = null;
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost request = new HttpPost(url);

    try {
        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params);
        request.setEntity(entity);

        HttpResponse response = httpClient.execute(request);

        bufferedReader = new BufferedReader(new InputStreamReader(response
                .getEntity().getContent()));
        StringBuilder stringBuilder = new StringBuilder("");
        StringBuilder stringBuilder2;
        String line = "";
        //String LineSeparator = System.getProperty("line.separator");
        while ((line = bufferedReader.readLine()) != null) {
            stringBuilder.append(line);
        }
        bufferedReader.close();

        ret = stringBuilder.toString();
        stringBuilder = null;

    } catch (ClientProtocolException e) {
        e.printStackTrace();
        // TODO: report an error
    } catch (IOException e) {
        e.printStackTrace();
        // TODO: report an error
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
                // TODO Auto-generated catch block
            }
        }
    }
    return ret;
}

我尝试在使用后将StringBuilder设置为null但没有帮助。我发布下面的logcat痕迹：

10-23 03:39:25.271: E/dalvikvm-heap(1011): Out of memory on a 4116282-byte allocation.
10-23 03:39:25.271: I/dalvikvm(1011): "AsyncTask #1" prio=5 tid=11 RUNNABLE
10-23 03:39:25.271: I/dalvikvm(1011):   | group="main" sCount=0 dsCount=0 obj=0x417c5e88 self=0x2a1d1db8
10-23 03:39:25.271: I/dalvikvm(1011):   | sysTid=1025 nice=10 sched=0/0 cgrp=apps/bg_non_interactive handle=706552328
10-23 03:39:25.271: I/dalvikvm(1011):   | state=R schedstat=( 3053328788 23773807212 6541 ) utm=241 stm=64 core=0
10-23 03:39:25.271: I/dalvikvm(1011):   at java.lang.String.<init>(String.java:~422)
10-23 03:39:25.271: I/dalvikvm(1011):   at java.lang.AbstractStringBuilder.toString(AbstractStringBuilder.java:642)
10-23 03:39:25.282: I/dalvikvm(1011):   at java.lang.StringBuilder.toString(StringBuilder.java:663)
10-23 03:39:25.282: I/dalvikvm(1011):   at com.dzo.dispatchcrude.driverapp.datalayer.ServerConnect.sendPostRequest(ServerConnect.java:128)
10-23 03:39:25.282: I/dalvikvm(1011):   at com.dzo.dispatchcrude.driverapp.datalayer.ServerConnect.Sync(ServerConnect.java:61)
10-23 03:39:25.282: I/dalvikvm(1011):   at com.dzo.dispatchcrude.driverapp.datalayer.DBSync.Login(DBSync.java:59)
10-23 03:39:25.282: I/dalvikvm(1011):   at com.dzo.dispatchcrude.driverapp.asynctask.SyncDBTask.doInBackground(SyncDBTask.java:52)
10-23 03:39:25.282: I/dalvikvm(1011):   at com.dzo.dispatchcrude.driverapp.asynctask.SyncDBTask.doInBackground(SyncDBTask.java:1)
10-23 03:39:25.282: I/dalvikvm(1011):   at android.os.AsyncTask$2.call(AsyncTask.java:287)
10-23 03:39:25.282: I/dalvikvm(1011):   at java.util.concurrent.FutureTask.run(FutureTask.java:234)
10-23 03:39:25.282: I/dalvikvm(1011):   at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
10-23 03:39:25.282: I/dalvikvm(1011):   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
10-23 03:39:25.282: I/dalvikvm(1011):   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
10-23 03:39:25.282: I/dalvikvm(1011):   at java.lang.Thread.run(Thread.java:841)
10-23 03:39:25.282: W/dalvikvm(1011): threadid=11: thread exiting with uncaught exception (group=0x41465700)
10-23 03:39:25.292: I/Choreographer(1011): Skipped 30 frames!  The application may be doing too much work on its main thread.
10-23 03:39:25.491: E/AndroidRuntime(1011): FATAL EXCEPTION: AsyncTask #1
10-23 03:39:25.491: E/AndroidRuntime(1011): java.lang.RuntimeException: An error occured while executing doInBackground()
10-23 03:39:25.491: E/AndroidRuntime(1011):     at android.os.AsyncTask$3.done(AsyncTask.java:299) 
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.FutureTask.run(FutureTask.java:239)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.lang.Thread.run(Thread.java:841)
10-23 03:39:25.491: E/AndroidRuntime(1011): Caused by: java.lang.OutOfMemoryError
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.lang.String.<init>(String.java:422)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.lang.AbstractStringBuilder.toString(AbstractStringBuilder.java:642)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.lang.StringBuilder.toString(StringBuilder.java:663)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at com.dzo.dispatchcrude.driverapp.datalayer.ServerConnect.sendPostRequest(ServerConnect.java:128)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at com.dzo.dispatchcrude.driverapp.datalayer.ServerConnect.Sync(ServerConnect.java:61)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at com.dzo.dispatchcrude.driverapp.datalayer.DBSync.Login(DBSync.java:59)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at com.dzo.dispatchcrude.driverapp.asynctask.SyncDBTask.doInBackground(SyncDBTask.java:52)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at com.dzo.dispatchcrude.driverapp.asynctask.SyncDBTask.doInBackground(SyncDBTask.java:1)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
10-23 03:39:25.491: E/AndroidRuntime(1011):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
10-23 03:39:25.491: E/AndroidRuntime(1011):     ... 4 more
10-23 03:39:28.091: E/WindowManager(1011): Activity com.dzo.dispatchcrude.driverapp.LoginActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{4178fcb0 V.E..... R.....ID 0,0-479,96} that was originally added here
10-23 03:39:28.091: E/WindowManager(1011): android.view.WindowLeaked: Activity com.dzo.dispatchcrude.driverapp.LoginActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{4178fcb0 V.E..... R.....ID 0,0-479,96} that was originally added here
10-23 03:39:28.091: E/WindowManager(1011):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:345)
10-23 03:39:28.091: E/WindowManager(1011):  at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:239)
10-23 03:39:28.091: E/WindowManager(1011):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
10-23 03:39:28.091: E/WindowManager(1011):  at android.app.Dialog.show(Dialog.java:281)
10-23 03:39:28.091: E/WindowManager(1011):  at com.dzo.dispatchcrude.driverapp.asynctask.SyncDBTask.onPreExecute(SyncDBTask.java:43)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.AsyncTask.execute(AsyncTask.java:534)
10-23 03:39:28.091: E/WindowManager(1011):  at com.dzo.dispatchcrude.driverapp.asynctask.LoginAsyncTask.onPostExecute(LoginAsyncTask.java:87)
10-23 03:39:28.091: E/WindowManager(1011):  at com.dzo.dispatchcrude.driverapp.asynctask.LoginAsyncTask.onPostExecute(LoginAsyncTask.java:1)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.AsyncTask.finish(AsyncTask.java:631)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.AsyncTask.access$600(AsyncTask.java:177)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-23 03:39:28.091: E/WindowManager(1011):  at android.os.Looper.loop(Looper.java:137)
10-23 03:39:28.091: E/WindowManager(1011):  at android.app.ActivityThread.main(ActivityThread.java:5103)
10-23 03:39:28.091: E/WindowManager(1011):  at java.lang.reflect.Method.invokeNative(Native Method)
10-23 03:39:28.091: E/WindowManager(1011):  at java.lang.reflect.Method.invoke(Method.java:525)
10-23 03:39:28.091: E/WindowManager(1011):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-23 03:39:28.091: E/WindowManager(1011):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-23 03:39:28.091: E/WindowManager(1011):  at dalvik.system.NativeStart.main(Native Method)
10-23 03:44:25.761: I/Process(1011): Sending signal. PID: 1011 SIG: 9

更新1

我再次尝试with this approach它在我的情况下也给了toString（）错误，它给了toString（）错误。我尝试使用Amit's answer时发生了同样的事情。是否有toString（）。

更新2

从while循环中删除了新的String构建器对象的创建，现在我没有使用行分隔符。但是，它没有太大的区别。该应用程序首次运行。但是，如果我尝试连续运行2-3次，则会再次出现同样的问题。

Answer 1

如果你没有足够的内存来存储你的字符串，你可以：释放一些内存，减少内存消耗，不要将字符串存储在内存中。

在您的情况下，您需要：

存储响应的内存（大约1.5 + mb）
字符串生成器的内存（约1.5 + mb）
结果字符串的内存（大约1.5 + mb连续内存，非常糟糕）
的BufferedReader / InputStreamReader的...等等。（一些公斤）

选项：

将响应转换为字符串without string builder。它将节省1 + mb。
以流形式读取响应并将其转换为不带字符串构建器的String。 Request/Response entity streaming。它将节省大约3mb
不要将响应转换为字符串。将其作为流读取并保存到文件或数据库，或者将流提供给流式JSON解析器。
在发送您的帖子请求之前尽可能多地释放内存并开始祈祷一切都会好起来。

Answer 2

只需将其添加到清单中的<application />标记：

android:largeHeap="true"

Answer 3

试试这个，

private String sendPostRequest(String url, List<NameValuePair> params)
        throws Exception {
    String ret = null;
    BufferedReader bufferedReader = null;
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost request = new HttpPost(url);

    try {
        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params);
        request.setEntity(entity);

        HttpResponse response = httpClient.execute(request);
        bufferedReader = new BufferedReader(new InputStreamReader(response
                .getEntity().getContent()));
        String line = "";
        while ((line = bufferedReader.readLine()) != null) {
           ret =ret +line;
        }
        bufferedReader.close();

    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return ret;
}

Android：Out of Memory错误StringBuilder

3 个答案: