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();

安全解决方案(正确关闭流):

Java 9及更新版本: 最终字节[]字节; try (inputStream) { 字节= inputStream.readAllBytes(); ｝

Java 8 and older: public static byte[] readAllBytes(InputStream inputStream) throws IOException { final int bufLen = 4 * 0x400; // 4KB byte[] buf = new byte[bufLen]; int readLen; IOException exception = null; try { try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) { while ((readLen = inputStream.read(buf, 0, bufLen)) != -1) outputStream.write(buf, 0, readLen); return outputStream.toByteArray(); } } catch (IOException e) { exception = e; throw e; } finally { if (exception == null) inputStream.close(); else try { inputStream.close(); } catch (IOException e) { exception.addSuppressed(e); } } }

Kotlin(当Java 9+不可访问时): @Throws (IOException::类) fun InputStream.readAllBytes(): ByteArray { val bufLen = 4 * 0x400 // 4KB val buf = ByteArray(bufLen) var readLen: Int = 0 ByteArrayOutputStream()。使用{o -> 这一点。使用{I -> i.read(buf, 0, bufLen)。{readLen = it} != -1) o.write(buf, 0, readLen) ｝ 返回o.toByteArray () ｝ ｝ 避免嵌套使用请看这里。

Scala(当Java 9+不可访问时)(By @Joan。Thx): def readAllBytes(inputStream: inputStream): Array[Byte] = Stream.continually (read)。takeWhile(_ != -1).map(_. tobyte).toArray . take (_

使用普通Java的DataInputStream和它的readFully方法(至少从Java 1.4开始存在):

...
byte[] bytes = new byte[(int) file.length()];
DataInputStream dis = new DataInputStream(new FileInputStream(file));
dis.readFully(bytes);
...

这个方法还有其他一些形式，但在这个用例中，我一直使用这个方法。

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();

你可以试试仙人掌:

byte[] array = new BytesOf(stream).bytes();

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;
   }
}