Java equivalent of Python's struct.pack?

问题:

Is there any function equivalent to Python's struct.pack in Java that allows me to pack and unpack values like this?

pump_on = struct.pack("IIHHI", 0, 0, 21, 96, 512)

回答1:

I think what you may be after is a ByteBuffer:

ByteBuffer pump_on_buf = ...
pump_on_buf.putInt(0);
pump_on_buf.putInt(0);
pump_on_buf.putShort(21);
pump_on_buf.putShort(96);
pump_on_buf.putInt(512);
byte[] pump_on = pump_on_buf.array();

回答2:

Something like this:

final ByteArrayOutputStream data = new ByteArrayOutputStream();
final DataOutputStream stream = new DataOutputStream(data);
stream.writeUTF(name);
stream.writeUTF(password);
final byte[] bytes = stream.toByteArray(); // there you go

Later, you can read that data:

final DataInputStream stream = new DataInputStream(
  new ByteArrayInputStream(bytes)
);
final String user = stream.readUTF();
final String password = stream.readUTF();

回答3:

Closest feature in core Java is Serialization. It converts object into byte sequence and back.

回答4:

I started development of project which is very close to Python Struct: java-binary-block-parser in JBBP it will look like

JBBPOut.BeginBin().Int(0,0).Short(21,96).Int(512).End().toByteArray();