java套接字发送压缩对象

Question

I want to compress my serializable objects and send them through java sockets. serializable object:

public class MyObject implements Serializable {

private int id;
private String name;
//getter,setter and equal, hashCode, toString methods

}



public class Sender {

private Socket clientSocket;

public void send(MyObject obj){
GZIPOutputStream gzipOut = new GZIPOutputStream(clientSocket.getOutputStream());
ObjectOutputStream objectOut = new ObjectOutputStream(gzipOut);
objectOut.writeObject(obj);
}
}



public class Receiver {

private Socket serverSocket;

public MyObject receive(){
GZIPInputStream gzipIn = new GZIPInputStream(serverSocket.getInputStream());
ObjectInputStream objectIn = new ObjectInputStream(gzipIn);
return (MyObject) objectIn.readObject();
}

}

this throws ZipException: Not in GZIP format at receiver side.

I won't close streams and sockets, because need to send multiple objects using the same stream and socket (performance wise)

Answer 1

ObjectStream is one of the most verbose serialisation formats available. Just about any other Serialization would be better for size. ObjectStreams have to flushed to send all the data and you can't send more than one stream in a connection, making it inefficient to just send one object per connection.

Compressed streams work best for large amounts of data, when you try to apply them to a few bytes, the result is larger, not smaller. Compressed Streams must be flushed to be read.

need to send multiple objects using the same stream and socket (performance wise)

This means you have to retain your GZIP/Object streams. You can't use more than one per stream.

public class ObjectSocket implements Closeable {
    private final Socket socket;
    private final ObjectOutputStream output;
    private final ObjectInputStream input;

    public ObjectSocket(Socket socket) throws IOException {
        this.socket = socket;
        this.output = new ObjectOutputStream(new DeflaterOutputStream(socket.getOutputStream()));
        this.input = new ObjectInputStream(new InflaterInputStream(socket.getInputStream()));
    }

    public void send(Serializable obj) throws IOException {
        output.writeObject(obj);
        output.reset();
        output.flush();
    }

    public <T extends Serializable> T receive() throws IOException, ClassNotFoundException {
        return (T) input.readObject();
    }

    @Override
    public void close() throws IOException {
        output.close();
        input.close();
        socket.close();
    }
}