1.15.2 通信报错

IDE：IntelliJ IDEA
IDE版本:2019.3
Forge版本: 31.1.9
Minecraft版本: 1.15.2

错误情况简述
服务端与客户端之间de通信问题。

报错日志

[17:44:20] [Render thread/ERROR] [ne.mi.fm.ne.si.IndexedMessageCodec/SIMPLENET]: Received empty payload on channel fml:handshake
[17:44:20] [Render thread/FATAL] [minecraft/ThreadTaskExecutor]: Error executing task on Client
java.lang.IndexOutOfBoundsException: index: 2, length: 123 (expected: range(0, 45))
	at io.netty.buffer.AbstractByteBuf.checkIndex0(AbstractByteBuf.java:1362) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.AbstractByteBuf.checkIndex(AbstractByteBuf.java:1357) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.PooledUnsafeDirectByteBuf.nioBuffer(PooledUnsafeDirectByteBuf.java:324) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.ByteBufUtil.decodeString(ByteBufUtil.java:769) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.AbstractByteBuf.toString(AbstractByteBuf.java:1222) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at net.minecraft.network.PacketBuffer.toString(PacketBuffer.java:1068) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.PacketBuffer.readString(PacketBuffer.java:319) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.PacketBuffer.readString(PacketBuffer.java:309) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at cc.kunss.packet.ToturPacket.<init>(ToturPacket.java:16) ~[main/:?] {re:classloading}
	at cc.kunss.packet.ToturPacket.decode(ToturPacket.java:43) ~[main/:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.lambda$tryDecode$0(IndexedMessageCodec.java:116) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_202] {}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.tryDecode(IndexedMessageCodec.java:116) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.consume(IndexedMessageCodec.java:157) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.SimpleChannel.networkEventListener(SimpleChannel.java:79) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:212) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:204) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.fml.network.NetworkInstance.dispatch(NetworkInstance.java:84) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.NetworkHooks.lambda$onCustomPayload$0(NetworkHooks.java:74) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_202] {}
	at net.minecraftforge.fml.network.NetworkHooks.onCustomPayload(NetworkHooks.java:74) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.client.network.play.ClientPlayNetHandler.handleCustomPayload(ClientPlayNetHandler.java:1868) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.network.play.server.SCustomPayloadPlayPacket.processPacket(SCustomPayloadPlayPacket.java:59) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.play.server.SCustomPayloadPlayPacket.processPacket(SCustomPayloadPlayPacket.java:11) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.run(SourceFile:144) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.RecursiveEventLoop.run(SourceFile:23) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.driveOne(SourceFile:118) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.drainTasks(SourceFile:103) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:898) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.run(Minecraft.java:554) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(SourceFile:204) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_202] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_202] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_202] {}
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_202] {}
	at net.minecraftforge.userdev.FMLUserdevClientLaunchProvider.lambda$launchService$0(FMLUserdevClientLaunchProvider.java:55) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-5.0.0-milestone.4.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-5.0.0-milestone.4.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-5.0.0-milestone.4.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-5.0.0-milestone.4.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-5.0.0-milestone.4.jar:?] {}
	at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:102) [forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {}

相关代码

package cc.kunss.packet;

import cc.kunss.channel.ToturMessage;
import net.minecraft.network.PacketBuffer;
import net.minecraftforge.fml.network.NetworkEvent;

import java.util.function.Supplier;

public class ToturPacket {

 private String name;
 private String json;
 private ToturMessage toturMessage;

 public ToturPacket(PacketBuffer packetBuffer) {
     json = packetBuffer.readString();
     toturMessage = new ToturMessage().fromJSON(json);
 }

 /**
  * 序列
  * @param s
  * @param packetBuffer
  */
 public static void encode(ToturPacket toturPacket, PacketBuffer packetBuffer) {
     packetBuffer.writeString(toturPacket.toturMessage.toJson());
 }

 /**
  * 处理 Handle
  * @param s
  * @param contextSupplier
  * @return true
  */
 public static boolean handle(ToturPacket s, Supplier<NetworkEvent.Context> contextSupplier) {
     System.out.println("ToturMod Debug: "+s.toturMessage.toString());
     return true;
 }

 public static ToturPacket decode(PacketBuffer packetBuffer) {
     return new ToturPacket(packetBuffer);
 }
}

注册数据包代码

INSTANCE.messageBuilder(ToturPacket.class, id++).encoder(ToturPacket::encode).decoder(ToturPacket::decode).consumer(ToturPacket::handle).add();

代码贴的不全，请把包处理整个类的代码贴上来，其次请补充Channel注册的代码。

ok ， 改了

如你要发送数据包，得自定义Channel，你的Channel注册在哪里了？

下面是例子：

这个注册了 没放出来

package cc.kunss.channel;

import cc.kunss.Totur;
import cc.kunss.packet.ToturPacket;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.network.NetworkRegistry;
import net.minecraftforge.fml.network.simple.SimpleChannel;

public class ToturNetwork {


   private final String PROTOCOL_VERSION = "1";
   private int id = 0;
   private static boolean channelEnable = false;

   public SimpleChannel INSTANCE = NetworkRegistry.newSimpleChannel(
           new ResourceLocation(Totur.MODID, "main"),
           () -> PROTOCOL_VERSION,
           (clientProtocol) -> clientProtocol.startsWith("ALLOWVANILLA \uD83D\uDC93\uD83D\uDC93\uD83D\uDC93") || PROTOCOL_VERSION.equals(clientProtocol),
           (clientProtocol) -> clientProtocol.startsWith("ALLOWVANILLA \uD83D\uDC93\uD83D\uDC93\uD83D\uDC93") || PROTOCOL_VERSION.equals(clientProtocol)
   );

   public ToturNetwork() {
       INSTANCE.messageBuilder(ToturPacket.class, id++).encoder(ToturPacket::encode).decoder(ToturPacket::decode).consumer(ToturPacket::handle).add();
   }
   
   public static boolean isChannelEnable() {
       return channelEnable;
   }

   public static void setChannelEnable(boolean channelEnable) {
       ToturNetwork.channelEnable = channelEnable;
   }


   public void sendToServer(Object o){
       INSTANCE.sendToServer(o);
   }

}

你有没有试过把INSTANCE改成静态的。
其次为什么你要用messageBuilder方法而不是registerMessage？

试过
现在换成了registerMessage
但是现在还是相同的问题

看起来是你的json太长了，超出了限制46的限制，把它分成两次试试。

{“a”:“b”}
这是传入的JSON 也没那么长吧…

你发送数据包的代码怎么写的？

IMessage.java

package cc.kunss.expand.message;

import com.google.gson.Gson;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import it.unimi.dsi.fastutil.Hash;

import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

public class IMessage {

    private Gson gson = new Gson();
    private Map<String,Object> map = new HashMap<>();

    public IMessage() {
    }

    public IMessage(Map<String, Object> map) {
        this.map = map;
    }

    public IMessage add(String path,Object o){
        map.put(path,o);
        return this;
    }

    public <T> Object get(String path, Class<?> c){
        return c.cast(map.get(path));
    }


    public IMessage addString(String path,String gbString) {
        char[] utfBytes = gbString.toCharArray();
        String unicodeBytes = "";
        for (int i = 0; i < utfBytes.length; i++) {
            String hexB = Integer.toHexString(utfBytes[i]);
            if (hexB.length() <= 2) {
                hexB = "00" + hexB;
            }
            unicodeBytes = unicodeBytes + "\\u" + hexB;
        }
        return add(path,unicodeBytes);
    }

    public IMessage fromMessage(byte[] bytes){
        ByteBuf buf = Unpooled.wrappedBuffer(bytes);
        this.map = gson.fromJson(buf.toString(StandardCharsets.UTF_8), HashMap.class);
        return this;
    }

    public String toJson(){
        return gson.toJson(map);
    }


    public byte[] toBytes(){
        System.out.println(toJson());
        return toJson().getBytes(StandardCharsets.UTF_8);
    }

    public ByteBuf toByteBuf(int index){
        byte[] bytes = toBytes();
        ByteBuf byteBuf = Unpooled.buffer(bytes.length +1);
        byteBuf.writeByte(index);
        byteBuf.writeBytes(bytes);
        return byteBuf;
    }
}

发送的类

package cc.kunss.expand.listener;

import cc.kunss.expand.Basics;
import cc.kunss.expand.message.IMessage;
import com.google.gson.Gson;
import org.bukkit.command.CommandSender;
import org.bukkit.craftbukkit.v1_15_R1.entity.CraftPlayer;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.scheduler.BukkitRunnable;

import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;

public class PlayerListener implements Listener{

    private Basics basics = Basics.getInstance();

    @EventHandler
    public void onJoin(PlayerJoinEvent e){
        Player player = e.getPlayer();
        try {
            Class<? extends CommandSender> senderClass = player.getClass();
            Method addChannel = senderClass.getDeclaredMethod("addChannel", String.class);
            addChannel.setAccessible(true);
            addChannel.invoke(player, "totur:main");
        } catch (Exception es) {
            es.printStackTrace();
        }
        IMessage iMessage = new IMessage();
        iMessage.add("a","b");
        byte[] bytes = iMessage.toByteBuf(0).array();
        e.getPlayer().sendPluginMessage(basics,"totur:main",bytes);
    }
}

ToturMessage 这个类的内容是什么？

package cc.kunss.channel;

import cc.kunss.Totur;
import com.google.gson.Gson;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;

import java.lang.reflect.Field;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

public class ToturMessage {

    private Map<String,Object> map = new HashMap<>();
    private Gson gson = new Gson();

    public ToturMessage() { }

    public ToturMessage(Map<String, Object> map) {
        this.map = map;
    }

    public ToturMessage fromJSON(String json){
        map = gson.fromJson(json,Map.class);
        return this;
    }

    public ToturMessage add(String path,Object o){
        map.put(path,o);
        return this;
    }

    public <T> T get(String path, Class<?> c){
        if (c.getTypeName().equals("int")){
            return get(path,Integer.class);
        }else if (c.getTypeName().equals("boolean")){
            return get(path,Boolean.class);
        }else if(c.getTypeName().equals("float")){
            return get(path,Float.class);
        }else if(c.getTypeName().equals("double")){
            return get(path,Double.class);
        }else if(c.getTypeName().equals("long")){
            return get(path,Long.class);
        }else if(c.getTypeName().equals("short")){
            return get(path,Short.class);
        }else {
            return (T) c.cast(map.get(path));
        }
    }

    public static void main(String[] args) {
        Class<?> c = int.class;
        System.out.println(c.getTypeName());
    }

    public Object assignment(Object o,String[] strings){
        for (String string : strings) {
            try {
                Field field = o.getClass().getDeclaredField(string);
                field.setAccessible(true);
                field.set(o,get(string,field.getType()));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return o;
    }

    @Override
    public String toString() {
        return gson.toJson(map);
    }

    public String toJson(){

        return gson.toJson(map);
    }

    public byte[] toBytes(){
        return toJson().getBytes(StandardCharsets.UTF_8);
    }
}

PlayerListener.java

byte[] bytes = iMessage.toByteBuf(0).array();

这里下个断点，看看具体的长度是多少。

bytes.lenght = 10

Basics.java是什么，贴出来。

e.getPlayer().sendPluginMessage(basics,"totur:main",bytes);
这个是什么函数，好像不是Forge里的。
其次

at io.netty.buffer.AbstractByteBuf.checkIndex0(AbstractByteBuf.java:1362) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.AbstractByteBuf.checkIndex(AbstractByteBuf.java:1357) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.PooledUnsafeDirectByteBuf.nioBuffer(PooledUnsafeDirectByteBuf.java:324) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.ByteBufUtil.decodeString(ByteBufUtil.java:769) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at io.netty.buffer.AbstractByteBuf.toString(AbstractByteBuf.java:1222) ~[netty-all-4.1.25.Final.jar:4.1.25.Final] {}
	at net.minecraft.network.PacketBuffer.toString(PacketBuffer.java:1068) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.PacketBuffer.readString(PacketBuffer.java:319) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}
	at net.minecraft.network.PacketBuffer.readString(PacketBuffer.java:309) ~[forge-1.15.2-31.1.9_mapped_stable_60-1.15.jar:?] {re:classloading}

按照这个顺序一层层打断点，看看到底传过来的是什么值。

看起来，输入的数据没有问题，应该是sendPluginMessage上出问题了。

这是服务端(PaperSpigot Bukkit)向客户端发送的方法

有可能有兼容性的问题，在传输数据的时候添加了某些数据头之类的东西。
看起来你得向Spigot官方询问这个问题，我并不会Spigot编程。

之前我测试还好着。。。

之前测试？

如果之前测试还好的，你恢复之前的代码就行。

好像是readString问题 之前没用到readString

问题解决了，请选择一个楼层作为答案。
如果都不是合适的答案，请自行补充一下解决方法作为答案。

传入的是byte数据 而我read的是String数据 因此无法读取到 应更换为readByte或者传入String