如何将整个输入流读到字节数组?
当前回答
public static byte[] getBytesFromInputStream(InputStream is) throws IOException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] buffer = new byte[0xFFFF];
for (int len = is.read(buffer); len != -1; len = is.read(buffer)) {
os.write(buffer, 0, len);
}
return os.toByteArray();
}
其他回答
如果由于某种原因,它不在表中,则将其包装在DataInputStream中,只需使用read来锤击它,直到它给您一个-1或您所要求的整个块。
public int readFully(InputStream in, byte[] data) throws IOException {
int offset = 0;
int bytesRead;
boolean read = false;
while ((bytesRead = in.read(data, offset, data.length - offset)) != -1) {
read = true;
offset += bytesRead;
if (offset >= data.length) {
break;
}
}
return (read) ? offset : -1;
}
另一种情况是在发送请求到服务器并等待响应后,通过流获得正确的字节数组。
/**
* Begin setup TCP connection to PC app
* to open integrate connection between mobile app and pc app (or mobile app)
*/
mSocket = new Socket(IP, port);
// mSocket.setSoTimeout(30000);
DataOutputStream mDos = new DataOutputStream(mSocket.getOutputStream());
String str = "MobileRequest#" + params[0] + "#<EOF>";
mDos.write(str.getBytes());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
/* Since data are accepted as byte, all of them will be collected in the
following byte array which initialised with accepted data length. */
DataInputStream mDis = new DataInputStream(mSocket.getInputStream());
byte[] data = new byte[mDis.available()];
// Collecting data into byte array
for (int i = 0; i < data.length; i++)
data[i] = mDis.readByte();
// Converting collected data in byte array into String.
String RESPONSE = new String(data);
如果您不想使用Apache common -io库,则此代码片段取自sun.misc.IOUtils类。它的速度几乎是使用ByteBuffers的普通实现的两倍:
public static byte[] readFully(InputStream is, int length, boolean readAll)
throws IOException {
byte[] output = {};
if (length == -1) length = Integer.MAX_VALUE;
int pos = 0;
while (pos < length) {
int bytesToRead;
if (pos >= output.length) { // Only expand when there's no room
bytesToRead = Math.min(length - pos, output.length + 1024);
if (output.length < pos + bytesToRead) {
output = Arrays.copyOf(output, pos + bytesToRead);
}
} else {
bytesToRead = output.length - pos;
}
int cc = is.read(output, pos, bytesToRead);
if (cc < 0) {
if (readAll && length != Integer.MAX_VALUE) {
throw new EOFException("Detect premature EOF");
} else {
if (output.length != pos) {
output = Arrays.copyOf(output, pos);
}
break;
}
}
pos += cc;
}
return output;
}
你可以使用Cactoos(我是它的开发者之一):
import org.cactoos.bytes.BytesOf;
byte[] array = new BytesOf(stream).asBytes();
你也可以将流转换为字符串:
import org.cactoos.text.TextOf;
String txt = new TextOf(stream).asString();
asBytes()和asString()方法都会抛出checked Exception。如果你不想捕获它,使用Unchecked*装饰器,例如:
import org.cactoos.bytes.BytesOf;
import org.cactoos.bytes.UncheckedBytes;
byte[] array = new UncheckedBytes(new BytesOf(stream)).asBytes();
下面的代码
public static byte[] serializeObj(Object obj) throws IOException {
ByteArrayOutputStream baOStream = new ByteArrayOutputStream();
ObjectOutputStream objOStream = new ObjectOutputStream(baOStream);
objOStream.writeObject(obj);
objOStream.flush();
objOStream.close();
return baOStream.toByteArray();
}
OR
BufferedImage img = ...
ByteArrayOutputStream baos = new ByteArrayOutputStream(1000);
ImageIO.write(img, "jpeg", baos);
baos.flush();
byte[] result = baos.toByteArray();
baos.close();
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