我有一个非常大的ByteBuffer
,大小约为几MB。当我运行ByteBuffer
时
FileChannel fc = new FileInputStream(new File(decodedUri)).getChannel();
ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
CharBuffer cb;
if (encoding == null)
encoding = "UTF-8";
cb = Charset.forName(encoding).decode(bb);
我每隔一段时间就会得到一个OutOfMemoryError
,其中堆栈跟踪可以追溯到Charset.decode
.正是这条线触发了错误。
cb = Charset.forName(encoding).decode(bb);
我该如何解决这个问题?
因为第一次启动应用程序时 内存错误 没有触发,并且只有第二次尝试启动它时,才会发生此错误。 我想知道是否需要从缓冲区中冲洗出来? 还是类似的东西?
如果你想分
块读取这个大文件,你可以像这样用AsyncTask
static class StreamTask extends AsyncTask<String, Void, Integer> {
private static final int BUFFER_LENGTH = 1024 * 8; // Adjust to taste
// Param #0 = file name
// Param #1 = charset name
@Override
protected Integer doInBackground(String... params) {
if (params.length != 2) {
throw new IllegalArgumentException();
}
int chars = 0;
CharsetDecoder cd = Charset.forName(params[1]).newDecoder();
try {
FileInputStream fin = new FileInputStream(params[0]);
try {
FileChannel fc = fin.getChannel();
ByteBuffer bb = ByteBuffer.allocateDirect(BUFFER_LENGTH);
CharBuffer cb = CharBuffer.allocate(BUFFER_LENGTH);
while (fc.read(bb) != -1) {
// Flip the buffer, decode the contents
bb.flip();
cd.decode(bb, cb, false); // You should probably look at CoderResult also.
// Flip & extract the decoded characters.
cb.flip();
chars += cb.remaining();
onCharacters(cb.array(), cb.position(), cb.remaining());
cb.clear();
// Prepare the buffer for reuse.
bb.compact();
}
// fc.read(..) returned -1 -> EOF, but bb may still contain
// stuff to decode.
bb.flip();
cd.decode(bb, cb, true);
cd.flush(cb);
cb.flip();
if (cb.remaining() > 0) {
chars += cb.remaining();
onCharacters(cb.array(), cb.position(), cb.remaining());
}
} finally {
fin.close();
}
} catch (IOException e) {
chars = -1;
}
return chars;
}
protected void onCharacters(char[] ch, int offset, int length) {
// Do something with the characters (still running in the AsyncTask thread)
}
}