查看此页面http://wiki.vg/Protocol，看来您未写入足够的数据或顺序不正确。您还需要使用varint，它是整数的一种特殊类型的数据表示形式。
与该问题有关的链接：
- 握手协议
- 封包格式
- 服务器Ping解释和示例（涉及握手）
状态ping的工作方式如下：
C->S : Handshake State=1C->S : RequestS->C : ResponseC->S : PingS->C : Pong
C是客户端，S是服务器
使用Wiki和提供的代码示例，我修改了您的代码以遵循整个状态请求。
public static void main(String [] args) throws IOException { String address = "162.244.165.111"; int port = 48040; InetSocketAddress host = new InetSocketAddress(address, port); Socket socket = new Socket(); System.out.println("Connecting..."); socket.connect(host, 3000); System.out.println("Done!"); System.out.println("Making streams..."); DataOutputStream output = new DataOutputStream(socket.getOutputStream()); DataInputStream input = new DataInputStream(socket.getInputStream()); System.out.println("Done!"); System.out.println("Attempting handshake... "+host.getAddress().toString()); byte [] handshakeMessage = createHandshakeMessage(address, port); // C->S : Handshake State=1 // send packet length and packet writeVarInt(output, handshakeMessage.length); output.write(handshakeMessage); // C->S : Request output.writeByte(0x01); //size is only 1 output.writeByte(0x00); //packet id for ping // S->C : Response int size = readVarInt(input); int packetId = readVarInt(input); if (packetId == -1) { throw new IOException("Premature end of stream."); } if (packetId != 0x00) { //we want a status response throw new IOException("Invalid packetID"); } int length = readVarInt(input); //length of json string if (length == -1) { throw new IOException("Premature end of stream."); } if (length == 0) { throw new IOException("Invalid string length."); } byte[] in = new byte[length]; input.readFully(in); //read json string String json = new String(in); // C->S : Ping long now = System.currentTimeMillis(); output.writeByte(0x09); //size of packet output.writeByte(0x01); //0x01 for ping output.writeLong(now); //time!? // S->C : Pong readVarInt(input); packetId = readVarInt(input); if (packetId == -1) { throw new IOException("Premature end of stream."); } if (packetId != 0x01) { throw new IOException("Invalid packetID"); } long pingtime = input.readLong(); //read response // print out server info System.out.println(json); System.out.println("Done!");}public static byte [] createHandshakeMessage(String host, int port) throws IOException { ByteArrayOutputStream buffer = new ByteArrayOutputStream(); DataOutputStream handshake = new DataOutputStream(buffer); handshake.writeByte(0x00); //packet id for handshake writeVarInt(handshake, 4); //protocol version writeString(handshake, host, StandardCharsets.UTF_8); handshake.writeShort(port); //port writeVarInt(handshake, 1); //state (1 for handshake) return buffer.toByteArray();}public static void writeString(DataOutputStream out, String string, Charset charset) throws IOException { byte [] bytes = string.getBytes(charset); writeVarInt(out, bytes.length); out.write(bytes);}public static void writeVarInt(DataOutputStream out, int paramInt) throws IOException { while (true) { if ((paramInt & 0xFFFFFF80) == 0) { out.writeByte(paramInt); return; } out.writeByte(paramInt & 0x7F | 0x80); paramInt >>>= 7; }}public static int readVarInt(DataInputStream in) throws IOException { int i = 0; int j = 0; while (true) { int k = in.readByte(); i |= (k & 0x7F) << j++ * 7; if (j > 5) throw new RuntimeException("VarInt too big"); if ((k & 0x80) != 128) break; } return i;}
