我正在尝试下载一个开始时不到22 MB的zip文件。我在这些异常之后更改了默认的BufferedInputStream，但仍然出现内存不足错误。
public void downloadFromUrl(String fileName) {
//avoid unknown host exception
try {
InetAddress i = InetAddress
.getByName("http://xxx/Android/" + fileName);
} catch (UnknownHostException e1) {
e1.printStackTrace();
}
try {
URL url = new URL("http://xxx/Android/" + fileName);
File file = new File(fileName);
long startTime = System.currentTimeMillis();
Log.d("DownloadManager", "download begining");
Log.d("DownloadManager", "download url:" + url);
Log.d("DownloadManager", "downloaded file name:" + fileName);
URLConnection ucon = url.openConnection();
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is, 23 * 1024);
ByteArrayBuffer baf = new ByteArrayBuffer(23 * 1024);
int current = 0;
while ((current = bis.read()) != -1) {
baf.append((byte) current);
}
FileOutputStream fos = new FileOutputStream(file);
fos.write(baf.toByteArray());
fos.close();
Log.d("DownloadManager",
"download ready in"
+ ((System.currentTimeMillis() - startTime) / 1000)
+ " sec");
} catch (IOException e) {
Log.d("DownloadManager", "Error: " + e);
}
}
堆栈：
10-28 10:18:16.885: DEBUG/ImageManager(1804): download begining
10-28 10:18:16.885: DEBUG/ImageManager(1804): download url:http://xxx/Android/Samples.zip
10-28 10:18:16.885: DEBUG/ImageManager(1804): downloaded file name:Samples.zip
10-28 10:18:17.204: INFO/global(1804): Default buffer size used in BufferedInputStream constructor. It would be better to be explicit if an 8k buffer is required.
10-28 10:18:17.845: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 1803 objects / 185168 bytes in 96ms
10-28 10:18:18.415: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 229 objects / 105296 bytes in 78ms
10-28 10:18:18.425: INFO/dalvikvm-heap(1804): Grow heap (frag case) to 3.184MB for 376848-byte allocation
10-28 10:18:18.545: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 109ms
10-28 10:18:20.555: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 44 objects / 190080 bytes in 65ms
10-28 10:18:20.575: INFO/dalvikvm-heap(1804): Grow heap (frag case) to 3.721MB for 753680-byte allocation
10-28 10:18:20.675: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 95ms
10-28 10:18:22.725: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 3 objects / 376904 bytes in 66ms
10-28 10:18:23.145: INFO/dalvikvm-heap(1804): Grow heap (frag case) to 4.799MB for 1507344-byte allocation
10-28 10:18:23.245: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 95ms
10-28 10:18:25.415: WARN/ActivityManager(59): Launch timeout has expired, giving up wake lock!
10-28 10:18:26.205: WARN/ActivityManager(59): Activity idle timeout for HistoryRecord{43ef1378 com.xxx.xxxe/.TabViewMain}
10-28 10:18:27.995: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 3 objects / 753736 bytes in 65ms
10-28 10:18:28.655: INFO/dalvikvm-heap(1804): Grow heap (frag case) to 6.956MB for 3014672-byte allocation
10-28 10:18:28.765: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 102ms
10-28 10:18:33.275: DEBUG/dalvikvm(123): GC_EXPLICIT freed 833 objects / 48984 bytes in 2059ms
10-28 10:18:37.275: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 3 objects / 1507400 bytes in 69ms
10-28 10:18:38.115: INFO/dalvikvm-heap(1804): Grow heap (frag case) to 11.268MB for 6029328-byte allocation
10-28 10:18:38.275: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 151ms
10-28 10:18:53.885: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 3 objects / 3014728 bytes in 70ms
10-28 10:18:53.895: INFO/dalvikvm-heap(1804): Forcing collection of SoftReferences for 12058640-byte allocation
10-28 10:18:54.055: DEBUG/dalvikvm(1804): GC_FOR_MALLOC freed 0 objects / 0 bytes in 158ms
10-28 10:18:54.055: ERROR/dalvikvm-heap(1804): Out of memory on a 12058640-byte allocation.
编辑：好的，我能够让this example正常工作，但即使拥有正确的权限，我也会收到权限被拒绝错误：
`10-2`8 11:33:15.478: WARN/System.err(1781): java.io.FileNotFoundException: /mnt/sdcard/testDirectory/Samples.zip (Permission denied)
答案 0 :(得分：6)
毫无疑问，您正试图在手机内存中创建一个22MB的字节阵列;大多数Android手机都没有那么多内存。您要做的是将文件流式传输到SD卡或内部存储器中：
// untested
final int BUFFER_SIZE = 23 * 1024;
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is, BUFFER_SIZE);
FileOutputStream fos = new FileOutputStream(file);
byte[] baf = new byte[BUFFER_SIZE];
int actual = 0;
while (actual != -1) {
fos.write(baf, 0, actual)
actual = bis.read(baf, 0, BUFFER_SIZE);
}
fos.close();
答案 1 :(得分：4)
下面是一个小方法来下载受Lie Ryan启发测试的大文件（感谢他），使用FileOutputStream来刷新缓冲区。
public void DownloadFromUrl(String fileURL, String fileName) { //this is the downloader method
try {
URL url = new URL( fileURL);
File file = new File(fileName);
file.createNewFile();
long startTime = System.currentTimeMillis();
Log.d("DownloadManager", "download begining");
Log.d("DownloadManager", "download url:" + url);
Log.d("DownloadManager", "downloaded file name:" + fileName);
/* Open a connection to that URL. */
URLConnection ucon = url.openConnection();
/*
* Define InputStreams to read from the URLConnection.
*/
InputStream is = ucon.getInputStream();
/*
* Read bytes to the Buffer until there is nothing more to read(-1) and write on the fly in the file.
*/
FileOutputStream fos = new FileOutputStream(file);
final int BUFFER_SIZE = 23 * 1024;
BufferedInputStream bis = new BufferedInputStream(is, BUFFER_SIZE);
byte[] baf = new byte[BUFFER_SIZE];
int actual = 0;
while (actual != -1) {
fos.write(baf, 0, actual);
actual = bis.read(baf, 0, BUFFER_SIZE);
}
fos.close();
Log.d("DownloadManager", "download ready in"
+ ((System.currentTimeMillis() - startTime) / 1000)
+ " sec");
} catch (IOException e) {
Log.d("DownloadManager", "Error: " + e);
}
}
答案 2 :(得分：1)
为什么使用ByteArrayBuffer？这是问题所在，你试图在其中存储22mb。