如何将整个输入流读到字节数组?
当前回答
这对我很有用,
if(inputStream != null){
ByteArrayOutputStream contentStream = readSourceContent(inputStream);
String stringContent = contentStream.toString();
byte[] byteArr = encodeString(stringContent);
}
readSourceContent ()
public static ByteArrayOutputStream readSourceContent(InputStream inputStream) throws IOException {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int nextChar;
try {
while ((nextChar = inputStream.read()) != -1) {
outputStream.write(nextChar);
}
outputStream.flush();
} catch (IOException e) {
throw new IOException("Exception occurred while reading content", e);
}
return outputStream;
}
encodeString()
public static byte[] encodeString(String content) throws UnsupportedEncodingException {
byte[] bytes;
try {
bytes = content.getBytes();
} catch (UnsupportedEncodingException e) {
String msg = ENCODING + " is unsupported encoding type";
log.error(msg,e);
throw new UnsupportedEncodingException(msg, e);
}
return bytes;
}
其他回答
我用这个。
public static byte[] toByteArray(InputStream is) throws IOException {
ByteArrayOutputStream output = new ByteArrayOutputStream();
try {
byte[] b = new byte[4096];
int n = 0;
while ((n = is.read(b)) != -1) {
output.write(b, 0, n);
}
return output.toByteArray();
} finally {
output.close();
}
}
下面是一个优化的版本,尽量避免复制数据字节:
private static byte[] loadStream (InputStream stream) throws IOException {
int available = stream.available();
int expectedSize = available > 0 ? available : -1;
return loadStream(stream, expectedSize);
}
private static byte[] loadStream (InputStream stream, int expectedSize) throws IOException {
int basicBufferSize = 0x4000;
int initialBufferSize = (expectedSize >= 0) ? expectedSize : basicBufferSize;
byte[] buf = new byte[initialBufferSize];
int pos = 0;
while (true) {
if (pos == buf.length) {
int readAhead = -1;
if (pos == expectedSize) {
readAhead = stream.read(); // test whether EOF is at expectedSize
if (readAhead == -1) {
return buf;
}
}
int newBufferSize = Math.max(2 * buf.length, basicBufferSize);
buf = Arrays.copyOf(buf, newBufferSize);
if (readAhead != -1) {
buf[pos++] = (byte)readAhead;
}
}
int len = stream.read(buf, pos, buf.length - pos);
if (len < 0) {
return Arrays.copyOf(buf, pos);
}
pos += len;
}
}
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();
请参阅InputStream.available()文档:
It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, File.length returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
while (true) {
int r = in.read(buffer);
if (r == -1) break;
out.write(buffer, 0, r);
}
byte[] ret = out.toByteArray();
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