java如何将字节数组转换为ByteArrayOutputStream

Question

我需要将字节数组转换为ByteArrayOutputStream，以便在屏幕上显示它

Answer 1

使用JDK/11，您可以使用writeBytes(byte b[])API，它最终会调用write(b, 0, b.length)，正如answer by Josh中建议的那样

/**
 * Writes the complete contents of the specified byte array
 * to this {@code ByteArrayOutputStream}.
 *
 * @apiNote
 * This method is equivalent to {@link #write(byte[],int,int)
 * write(b, 0, b.length)}.
 *
 * @param   b     the data.
 * @throws  NullPointerException if {@code b} is {@code null}.
 * @since   11
 */
public void writeBytes(byte b[]) {
    write(b, 0, b.length);
}

示例代码将简单地转换为

byte[] bytes = new byte[100];
ByteArrayOutputStream baos = new ByteArrayOutputStream(bytes.length);
baos.writeBytes(bytes);

Answer 2

无法显示ByteArrayOutputStream。我猜你想做的是

byte[] bytes = ...
String text = new String(bytes, "UTF-8"); // or some other encoding.
// display text.

您可以让ByteArrayOutputStream执行类似的操作，但这不是显而易见的、有效的或最佳实践（因为您无法控制所使用的编码）

Answer 3

byte[] bytes = ....;
ByteArrayOutputStream baos = new ByteArrayOutputStream(bytes.length);
baos.write(bytes, 0, bytes.length);

方法说明：

Writes len bytes from the specified byte array starting at offset off to this byte array output stream.