尽管有缓冲，但从 Android 应用上传大文件仍会出现内存不足错误答案

【问题标题】：Uploading large file from Android app gives out of memory error despite buffering尽管有缓冲，但从 Android 应用上传大文件仍会出现内存不足错误
【发布时间】：2016-08-26 13:51:45
【问题描述】：

我正在尝试使用 POST 将大型视频文件（约 900mb）上传到 PHP 服务器。我正在使用 FileInputStream 读取文件并使用 DataOutputStream 将其写入 HTTPUrlConnection。尽管有 1024 字节的缓冲区，我最终还是会内存不足，下面是我的代码

String result = "";

String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
try {

    FileInputStream fileInputStream = new FileInputStream(
            new File(path));

    URL url = new URL(ServerUtils.ip + "upload.php");
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setDoInput(true);
    conn.setDoOutput(true);
    conn.setUseCaches(false);
    conn.setRequestMethod("POST");
    conn.setRequestProperty("Connection", "Keep-Alive");
    conn.setRequestProperty("Content-Type",
            "multipart/form-data;boundary=" + boundary);

    DataOutputStream dos = new DataOutputStream(new BufferedOutputStream(conn.getOutputStream()));
    dos.writeBytes(twoHyphens + boundary + lineEnd);
    dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\""
            + path + "\"" + lineEnd);
    dos.writeBytes(lineEnd);

    int count;
    byte[]  buffer = new byte[1024];
    while((count = fileInputStream.read(buffer)) > 0){
        dos.write(buffer, 0 , count);
    }

    dos.writeBytes(lineEnd);
    dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

    fileInputStream.close();
    dos.flush();
    dos.close();
    BufferedReader rd = new BufferedReader(new InputStreamReader(
            conn.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        result += line;
    }
    rd.close();

} catch (Exception e) {
    e.printStackTrace();
}

这是错误

Throwing OutOfMemoryError "Failed to allocate a 28 byte allocation with 0 free bytes and 3GB until OOM" (recursive case)
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art: "FinalizerDaemon" daemon prio=5 tid=5 Runnable
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:   | group="system" sCount=0 dsCount=0 obj=0x32c071c0 self=0xae085200
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:   | sysTid=4387 nice=0 cgrp=default sched=0/0 handle=0xb42ff930
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:   | state=R schedstat=( 862325936 45498700 428 ) utm=43 stm=43 core=2 HZ=100
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:   | stack=0xb41fd000-0xb41ff000 stackSize=1038KB
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:   | held mutexes= "mutator lock"(shared held)
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:     at com.android.internal.os.BinderInternal$GcWatcher.finalize(BinderInternal.java:53)
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:     at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:202)
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:     at java.lang.Daemons$FinalizerDaemon.run(Daemons.java:185)
08-26 14:48:56.276 4379-4387/com.hamzahrmalik.groupwatch W/art:     at java.lang.Thread.run(Thread.java:818)
08-26 14:48:56.277 4379-4387/com.hamzahrmalik.groupwatch E/System: Uncaught exception thrown by finalizer
08-26 14:48:56.277 4379-4387/com.hamzahrmalik.groupwatch I/art: Waiting for a blocking GC Alloc
08-26 14:48:56.277 4379-4722/com.hamzahrmalik.groupwatch I/art: Waiting for a blocking GC Alloc
08-26 14:48:56.277 4379-4414/com.hamzahrmalik.groupwatch I/art: Waiting for a blocking GC Alloc
08-26 14:48:56.313 4379-4385/com.hamzahrmalik.groupwatch I/art: Clamp target GC heap from 208MB to 192MB
08-26 14:48:56.313 4379-4385/com.hamzahrmalik.groupwatch I/art: Alloc concurrent mark sweep GC freed 0(0B) AllocSpace objects, 0(0B) LOS objects, 0% free, 192MB/192MB, paused 1.360ms total 38.641ms
08-26 14:48:56.313 4379-4387/com.hamzahrmalik.groupwatch I/art: WaitForGcToComplete blocked for 36.526ms for cause Alloc
08-26 14:48:56.313 4379-4387/com.hamzahrmalik.groupwatch I/art: Starting a blocking GC Alloc
08-26 14:48:56.313 4379-4722/com.hamzahrmalik.groupwatch I/art: WaitForGcToComplete blocked for 108.918ms for cause Alloc
08-26 14:48:56.313 4379-4722/com.hamzahrmalik.groupwatch I/art: Starting a blocking GC Alloc
08-26 14:48:56.313 4379-4414/com.hamzahrmalik.groupwatch I/art: Waiting for a blocking GC Alloc
08-26 14:48:56.314 4379-4387/com.hamzahrmalik.groupwatch I/art: Waiting for a blocking GC Alloc
08-26 14:48:56.314 4379-4385/com.hamzahrmalik.groupwatch W/art: Throwing OutOfMemoryError "Failed to allocate a 28 byte allocation with 0 free bytes and 3GB until OOM" (recursive case)
08-26 14:48:56.338 4379-4385/com.hamzahrmalik.groupwatch W/art: "JDWP" daemon prio=5 tid=3 Runnable
08-26 14:48:56.339 4379-4385/com.hamzahrmalik.groupwatch W/art:   | group="system" sCount=0 dsCount=0 obj=0x32c07100 self=0xae083900
08-26 14:48:56.339 4379-4385/com.hamzahrmalik.groupwatch W/art:   | sysTid=4385 nice=0 cgrp=default sched=0/0 handle=0xb455a930
08-26 14:48:56.339 4379-4385/com.hamzahrmalik.groupwatch W/art:   | state=R schedstat=( 298147394 24472603 183 ) utm=25 stm=4 core=3 HZ=100
08-26 14:48:56.339 4379-4385/com.hamzahrmalik.groupwatch W/art:   | stack=0xb445e000-0xb4460000 stackSize=1014KB
08-26 14:48:56.339 4379-4385/com.hamzahrmalik.groupwatch W/art:   | held mutexes= "mutator lock"(shared held)

【问题讨论】：

也许问题在于您从服务器获得的响应，您将其存储在 String 中。
您可以尝试使用conn.setChunkedStreamingMode(....) 选项来防止系统在发送请求之前对其进行缓冲。
@Titus 它在任何响应到来之前就崩溃了。此外，回应仅仅是“成功”。我试试谢谢
我明白了，在这种情况下，问题可能是请求在发送之前在系统上被缓冲，您可以通过使用setChunkedStreamingMode(....)来防止这种情况
是的，我现在正在尝试，如果有效，会通知您

标签： java php android out-of-memory dataoutputstream

【解决方案1】：

这个问题很可能是因为系统在将请求发送到服务器之前正在缓冲请求。为了防止这种情况（请求表单被缓冲），您可以使用：

conn.setChunkedStreamingMode(....);

其中conn 是HttpURLConnection 的一个实例。

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【讨论】：