我尝试获取远程服务器的 MOTD,但无法获取颜色。当 MOTD 为彩色时,该插件不起作用。 我知道原因,但不知道如何解决。
public PingServer(String host, int port) {
this.host = host;
this.port = port;
try {
socket.connect(new InetSocketAddress(host, port));
OutputStream out = socket.getOutputStream();
InputStream in = socket.getInputStream();
out.write(0xFE);
int b;
StringBuffer str = new StringBuffer();
while ((b = in.read()) != -1) {
if (b != 0 && b > 16 && b != 255 && b != 23 && b != 24) {
str.append((char) b);
}
}
data = str.toString().split("§");
data[0] = data[0].substring(1, data[0].length());
} catch (IOException e) {
e.printStackTrace();
}
}
根据specification ,插件将得到如下响应:MOTD§ONLINEPLAYERS§MAXPLAYERS
,应在 §
上拆分以获得不同的部分。但是,§
也用于 chat messages ,我不知道如何区分两者。我该如何解决这个问题?
最佳答案
您当前正在使用legacy server list ping ,专为 beta 1.8 至 1.3 设计。只需发送FE
即可触发该事件。到服务器。虽然当前的服务器仍然支持此 ping,但它非常旧并且有几个缺陷(包括您发现的缺陷)。
您应该执行 current ping 。虽然这稍微复杂一些,但您不需要实现大部分协议(protocol)来实际执行它。
您只需要了解该协议(protocol)的一个复杂部分:VarInt
s。这些有点复杂,因为它们根据值占用不同数量的字节。因此,数据包长度可能有点难以计算。
/** See http://wiki.vg/Protocol_version_numbers. 47 = 1.8.x */
private static final int PROTOCOL_VERSION_NUMBER = 47;
private static final int STATUS_PROTOCOL = 1;
private static final JsonParser PARSER = new JsonParser();
/** Pings a server, returning the MOTD */
public static String pingServer(String host, int port) {
this.host = host;
this.port = port;
try {
socket.connect(new InetSocketAddress(host, port));
OutputStream out = socket.getOutputStream();
InputStream in = socket.getInputStream();
byte[] hostBytes = host.getBytes("UTF-8");
int handshakeLength =
varIntLength(0) + // Packet ID
varIntLength(PROTOCOL_VERSION_NUMBER) + // Protocol version number
varIntLength(hostBytes.length) + hostBytes.length + // Host
2 + // Port
varIntLength(STATUS_PROTOCOL); // Next state
writeVarInt(handshakeLength, out);
writeVarInt(0, out); // Handshake packet
writeVarInt(PROTOCOL_VERSION_NUMBER, out);
writeVarInt(hostBytes.length, out);
out.write(hostBytes);
out.write((port & 0xFF00) >> 8);
out.write(port & 0xFF);
writeVarInt(STATUS_PROTOCOL, out);
writeVarInt(varIntLength(0));
writeVarInt(0); // Request packet (has no payload)
int packetLength = readVarInt(in);
int payloadLength = readVarInt(in);
byte[] payloadBytes = new int[payloadLength];
int readLength = in.read(payloadBytes);
if (readLength < payloadLength) {
throw new RuntimeException("Unexpected end of stream");
}
String payload = new String(payloadBytes, "UTF-8");
// Now you need to parse the JSON; this is using GSON
// See https://github.com/google/gson
// and http://www.javadoc.io/doc/com.google.code.gson/gson/2.8.0
JsonObject element = (JsonObject) PARSER.parse(payload);
JsonElement description = element.get("description");
// This is a naive implementation; it assumes a specific format for the description
// rather than parsing the entire chat format. But it works for the way the
// notchian server impmlements the ping.
String motd = ((JsonObject) description).get("text").getAsString();
return motd;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
public static int varIntLength(int value) {
int length = 0;
do {
// Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
value >>>= 7;
length++;
} while (value != 0);
}
public static void writeVarInt(int value, OutputStream out) {
do {
byte temp = (byte)(value & 0b01111111);
// Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
value >>>= 7;
if (value != 0) {
temp |= 0b10000000;
}
out.write(temp);
} while (value != 0);
}
public static int readVarInt(InputStream in) {
int numRead = 0;
int result = 0;
int read;
do {
read = in.read();
if (read < 0) {
throw new RuntimeException("Unexpected end of stream");
}
int value = (read & 0b01111111);
result |= (value << (7 * numRead));
numRead++;
if (numRead > 5) {
throw new RuntimeException("VarInt is too big");
}
} while ((read & 0b10000000) != 0);
return result;
}
当前 ping 确实使用 JSON,这意味着您需要使用 GSON。此外,此实现对 chat 做出了一些假设。格式;此实现可能会在更完整地实现聊天的自定义服务器上中断,但它适用于嵌入 §
的服务器。进入 motd,而不是使用更完整的聊天系统(这包括 Notchian 服务器实现)。
如果您需要使用旧版 ping,则可以假设倒数第二个 §
标志着 MOTD 的结束(而不是第一个 §
)。像这样的事情:
String legacyPingResult = str.toString();
String[] data = new String[3];
int splitPoint2 = legacyPingResult.lastIndexOf('§');
int splitPoint1 = legacyPingResult.lastIndexOf('§', splitPoint2 - 1);
data[0] = legacyPingResult.substring(0, splitPoint1);
data[1] = legacyPingResult.substring(splitPoint1 + 1, splitPoint2);
data[2] = legacyPingResult.substring(splitPoint2 + 1);
但是,我仍然不建议使用旧版 ping。
关于java - Minecraft - Bukkit socket ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42509251/