如何使用 Gson 在 java 中使用非本机字段序列化 class？
How to serialize a class with non native fields in java with Gson?
我目前正在为 Minecraft 中的 Spigot 插件编写自己的 NPC class。
import com.mojang.authlib.GameProfile;
import com.mojang.authlib.properties.Property;
import net.minecraft.server.v1_16_R1.*;
import org.bukkit.Bukkit;
import org.bukkit.Location;
import org.bukkit.craftbukkit.v1_16_R1.CraftServer;
import org.bukkit.craftbukkit.v1_16_R1.CraftWorld;
import org.bukkit.craftbukkit.v1_16_R1.entity.CraftPlayer;
import org.bukkit.craftbukkit.v1_16_R1.util.CraftChatMessage;
import org.bukkit.entity.Player;
import org.bukkit.plugin.Plugin;
import org.bukkit.scheduler.BukkitRunnable;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class NPC extends EntityPlayer implements Serializable {
private final int entityId;
private Location location;
private GameProfile gameprofile;
private final List<Player> recipients;
private Recipient recipient_type;
private String display_name;
private String tablist_name;
private final DataWatcher dataWatcher;
private final DataWatcherObject<Byte> object_entity_state;
private final DataWatcherObject<String> object_customName;
private final DataWatcherObject<Boolean> object_isSilent;
private final DataWatcherObject<Boolean> object_hasGravity;
private final DataWatcherObject<Boolean> object_isCustomNameVisible;
private boolean isDestroyed;
private final Plugin plugin;
public NPC(String name, Location location, UUID uuid, WorldServer worldServer, Plugin plugin) {
super(((CraftServer) Bukkit.getServer()).getServer(), worldServer, new GameProfile(uuid, name), new PlayerInteractManager(worldServer));
this.plugin = plugin;
this.display_name = name;
this.tablist_name = name;
this.recipient_type = Recipient.ALL;
this.recipients = new ArrayList<>();
this.entityId = (int) Math.ceil(Math.random() * 1000);
this.gameprofile = new GameProfile(uuid, display_name);
this.location = location;
this.dataWatcher = new DataWatcher(null);
this.dataWatcher.register(object_entity_state = new DataWatcherObject<>(0, DataWatcherRegistry.a), (byte) 0);
this.dataWatcher.register(new DataWatcherObject<>(1, DataWatcherRegistry.b), 300);
this.dataWatcher.register(object_customName = new DataWatcherObject<>(2, DataWatcherRegistry.d), "");
this.dataWatcher.register(object_isCustomNameVisible = new DataWatcherObject<>(3, DataWatcherRegistry.i),false);
this.dataWatcher.register(object_isSilent = new DataWatcherObject<>(4, DataWatcherRegistry.i), false);
this.dataWatcher.register(object_hasGravity = new DataWatcherObject<>(5, DataWatcherRegistry.i), false);
this.dataWatcher.register(new DataWatcherObject<>(9, DataWatcherRegistry.i), false);
this.dataWatcher.register(new DataWatcherObject<>(6, DataWatcherRegistry.a), (byte) 0);
this.dataWatcher.register(new DataWatcherObject<>(7, DataWatcherRegistry.c), 20.0F);
this.dataWatcher.register(new DataWatcherObject<>(8, DataWatcherRegistry.b), 0);
this.dataWatcher.register(new DataWatcherObject<>(10, DataWatcherRegistry.b), 0);
this.dataWatcher.register(new DataWatcherObject<>(11, DataWatcherRegistry.c), 0.0F);
this.dataWatcher.register(new DataWatcherObject<>(12, DataWatcherRegistry.b), 20);
this.dataWatcher.register(new DataWatcherObject<>(13, DataWatcherRegistry.a), (byte) 127);
this.dataWatcher.register(new DataWatcherObject<>(14, DataWatcherRegistry.a), (byte) 1);
this.dataWatcher.register(new DataWatcherObject<>(15, DataWatcherRegistry.p), new NBTTagCompound());
this.dataWatcher.register(new DataWatcherObject<>(16, DataWatcherRegistry.p), new NBTTagCompound());
}
public NPC(String name, Location location, Plugin plugin) {
this(name, location, UUID.randomUUID(), ((CraftWorld) Bukkit.getWorlds().get(0)).getHandle(), plugin);
}
public NPC(String name, Location location, UUID uuid, Plugin plugin) {
this(name, location, uuid, ((CraftWorld) Bukkit.getWorlds().get(0)).getHandle(), plugin);
}
// public Map<String, Object> serialize() {
// Map<String, Object> result = new HashMap<>();
// BeanInfo info = null;
// try {
// info = Introspector.getBeanInfo(this.getClass());
// } catch (IntrospectionException e) {
// e.printStackTrace();
// }
// for (PropertyDescriptor pd : info.getPropertyDescriptors()) {
// Method reader = pd.getReadMethod();
// if (reader != null) {
// try {
// result.put(pd.getName(), reader.invoke(this));
// } catch (IllegalAccessException | InvocationTargetException e) {
// e.printStackTrace();
// }
// }
// }
// return result;
// }
/*
* view all the packet receivers
*/
public List<Player> getRecipients() {
return this.recipients;
}
/*
* get the signature and skin from the gameprofile
*/
public Property getSkin() {
if (this.gameprofile.getProperties().isEmpty())
return null;
return (Property) this.gameprofile.getProperties().get("textures").toArray()[0];
}
/*
* get npc id
*/
public int getEntityId() {
return entityId;
}
/*
* get npc location
*/
public Location getLocation() {
return location;
}
/*
* get npc gameprofile
*/
public GameProfile getGameprofile() {
return gameprofile;
}
/*
* get all the packet receivers
*/
public Recipient getRecipient_type() {
return recipient_type;
}
/*
* get npc displayname above head
*/
public String getDisplay_name() {
return display_name;
}
/*
* get npc displayname in tablist
*/
public String getTablist_name() {
return tablist_name;
}
/*
* check if npc is deleted
*/
public boolean isDestroyed() {
return isDestroyed;
}
/*
* get plugin
*/
public Plugin getPlugin() {
return plugin;
}
/*
* add Player so it receives the update packets
*/
public void addRecipient(Player p) {
this.recipients.add(p);
}
/*
* Remove Player that receives the update packets
*/
public void removeRecipient(Player p) {
this.recipients.remove(p);
}
/*
* toggle if the packet receivers are all the players online or a specicif group.
* If set to ALL (online) then the set/get recipient will have no effect
*/
public void setRecipientType(Recipient recipient_type) {
this.recipient_type = recipient_type;
}
/*
* spawn the npc, this should be the last function after init.
*/
public void spawn(boolean tablist, boolean fix_head) {
PacketPlayOutNamedEntitySpawn packet = new PacketPlayOutNamedEntitySpawn();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", this.gameprofile.getId());
this.setField(packet, "c", location.getX());
this.setField(packet, "d", location.getY());
this.setField(packet, "e", location.getZ());
this.setField(packet, "f", fix_head ? (byte) ((int) location.getYaw() * 256.0F / 360.0F) : 0);
this.setField(packet, "g", fix_head ? (byte) ((int) location.getPitch() * 256.0F / 360.0F) : 0);
// this.setField(packet, "i", this.dataWatcher);
this.addToTabList();
this.sendPacket(packet);
this.isDestroyed = false;
//Delay is required to commit the tablist changes
new BukkitRunnable() {
@Override
public void run() {
if (!tablist) removeFromTabList();
}
}.runTaskLater(this.plugin, 5);
}
/*
* put items in inventory, see https://www.google.nl/search?q=bukkit+inventory+slots&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjr9v_FxvjaAhUFMuwKHQi7ALUQ_AUICigB&biw=1920&bih=974#imgrc=QUECAbUohgZxbM:
* for more info
*/
public void setEquipment(EnumItemSlot slot, ItemStack item) {
PacketPlayOutEntityEquipment packet = new PacketPlayOutEntityEquipment();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", slot);
this.setField(packet, "c", item);
this.sendPacket(packet);
}
/*
* set the name above the player
*/
public void setDisplayNameAboveHead(String name) throws IOException {
if(name.length() > 16) throw new IOException("Name cannot be longer than 16 chatacters.");
this.display_name = name;
this.reloadNpc();
}
/*
* set the name above the player and tablist.
*/
public void setDisplayName(String name) throws IOException {
this.setDisplayNameAboveHead(name);
this.setTablistName(name);
}
/*
* set custom name in tablist
*/
public void setTablistName(String name) {
this.tablist_name = name;
this.updateToTabList();
}
/*
* respawn the npc and refresh all comitted changes
*/
public void reloadNpc() {
this.updateProfile();
if(!this.isDestroyed) {
PacketPlayOutEntityDestroy packet = new PacketPlayOutEntityDestroy(this.entityId);
this.sendPacket(packet);
this.spawn(true, true);
}
}
/*
* Update/Refresh the gameprofile that contains UUID, Name, Skin.
*/
private void updateProfile() {
Property skin = this.getSkin();
this.gameprofile = new GameProfile(this.gameprofile.getId(), this.display_name);
if (skin != null)
this.setSkin(skin.getValue(), skin.getSignature());
}
/*
* set the texture and signature in the gameprofile, to submit it you must reload player.
*/
public void setSkin(String texture, String signature) {
this.gameprofile.getProperties().put("textures", new Property("textures", texture, signature));
}
/*
* remove npc from the recipient's tablist
*/
public void removeFromTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.REMOVE_PLAYER);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* update npc to the recipient's tablist
*/
public void updateToTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.UPDATE_DISPLAY_NAME);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* add npc from the recipient's tablist
*/
public void addToTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.ADD_PLAYER);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* set player action, such as shift, onfire, ect recommending to use 'public void setAction(Action action)'.
*/
public void setAction(byte action) {
this.setMetaData(action);
}
/*
* set player action, such as shift, onfire, ect.
*/
public void setAction(Action action) {
this.setMetaData(action.build());
}
/*
* make sure the npc is near a bed or on it.
*/
// public void setSleep(boolean state) {
// if (state) {
// Location bed = new Location(this.location.getWorld(), 0, 0, 0);
// PacketPlayOutBed packet = new PacketPlayOutBed();
// this.setField(packet, "a", this.entityId);
// this.setField(packet, "b", new BlockPosition(bed.getX(), bed.getY(), bed.getZ()));
//
// for (Player p : (this.recipient_type == Recipient.ALL ? Bukkit.getOnlinePlayers() : this.recipients)) {
// ((CraftPlayer) p).sendBlockChange(bed, Material.BED_BLOCK, (byte) 0);
// ((CraftPlayer) p).sendBlockChange(bed.add(0, 0, 1), Material.BED_BLOCK, (byte) 2);
// }
//
// this.sendPacket(packet);
// this.teleport(location.clone().add(0, 0.3, 0), false);
//
// } else {
// this.setAnimation(NPCAnimation.LEAVE_BED);
// this.teleport(location.clone().subtract(0, 0.3, 0), true);
// }
// }
/*
* delete the npc from the server.
*/
public void destroy() {
PacketPlayOutEntityDestroy packet = new PacketPlayOutEntityDestroy(this.entityId);
this.removeFromTabList();
this.sendPacket(packet);
this.isDestroyed = true;
}
/*
* set npc status such as die or hurt. I recommond to use method 'public void setStatus(NPCStatus status)'
*/
public void setStatus(byte status) {
PacketPlayOutEntityStatus packet = new PacketPlayOutEntityStatus();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", status);
this.sendPacket(packet);
}
/*
* set npc status such as die or hurt.
*/
public void setStatus(NPCStatus status) {
this.setStatus((byte) status.getId());
}
/*
* set npc effect such as Night Vision or something else.
*/
public void setEffect(MobEffect effect) {
this.sendPacket(new PacketPlayOutEntityEffect(this.entityId, effect));
}
/*
* set npc animation such as Swing arm ect. I recommend using method 'public void setAnimation(NPCAnimation animation)'
*/
public void setAnimation(byte animation) {
PacketPlayOutAnimation packet = new PacketPlayOutAnimation();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", animation);
this.sendPacket(packet);
}
/*
* set npc animation such as Swing arm ect.
*/
public void setAnimation(NPCAnimation animation) {
this.setAnimation((byte) animation.getId());
}
/*
* teleport npc to different location
*/
public void teleport(Location location, Boolean onGround) {
PacketPlayOutEntityTeleport packet = new PacketPlayOutEntityTeleport();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", location.getX());
this.setField(packet, "c", location.getY());
this.setField(packet, "d", location.getZ());
this.setField(packet, "e", (byte) location.getYaw());
this.setField(packet, "f", (byte) location.getPitch());
this.setField(packet, "g", onGround);
this.sendPacket(packet);
this.rotateHead(location.getPitch(), location.getYaw());
this.location = location;
}
/*
* rotate npc head to pitch and yaw.
*/
public void rotateHead(float pitch, float yaw) {
PacketPlayOutEntity.PacketPlayOutEntityLook packet = new PacketPlayOutEntity.PacketPlayOutEntityLook(this.entityId, getFixRotation(yaw), (byte) pitch, true);
PacketPlayOutEntityHeadRotation packet_1 = new PacketPlayOutEntityHeadRotation();
this.setField(packet_1, "a", this.entityId);
this.setField(packet_1, "b", getFixRotation(yaw));
this.sendPacket(packet);
this.sendPacket(packet_1);
}
/*
* These methods below are not usefull.
*/
private <T> void setDataWatcherObject(DataWatcherObject<T> datawatcherobject, Object t0) {
try {
Method m = this.dataWatcher.getClass().getDeclaredMethod("registerObject", DataWatcherObject.class,
Object.class);
m.setAccessible(true);
m.invoke(this.dataWatcher, datawatcherobject, t0);
} catch (Exception e) {
e.printStackTrace();
}
}
private void setMetaData(byte data) {
this.setDataWatcherObject(this.object_entity_state, data);
PacketPlayOutEntityMetadata packet = new PacketPlayOutEntityMetadata(this.entityId, this.dataWatcher, true);
sendPacket(packet);
}
private byte getFixRotation(float yawpitch) {
return (byte) ((int) (this.location.getYaw() * 256.0F / 360.0F));
}
private Object getField(Object obj, String field_name) {
try {
Field field = obj.getClass().getDeclaredField(field_name);
field.setAccessible(true);
return field.get(obj);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private void setField(Object obj, String field_name, Object value) {
try {
Field field = obj.getClass().getDeclaredField(field_name);
field.setAccessible(true);
field.set(obj, value);
} catch (Exception e) {
e.printStackTrace();
}
}
private void sendPacket(Packet<?> packet, Player player) {
((CraftPlayer) player).getHandle().playerConnection.sendPacket(packet);
}
private void sendPacket(Packet<?> packet) {
for (Player p : (this.recipient_type == Recipient.ALL ? Bukkit.getOnlinePlayers() : this.recipients)) {
this.sendPacket(packet, p);
}
}
enum Recipient {
ALL, LISTED_RECIPIENTS
}
enum NPCAnimation {
SWING_MAIN_HAND(0),
TAKE_DAMAGE(1),
LEAVE_BED(2),
SWING_OFFHAND(3),
CRITICAL_EFFECT(4),
MAGIC_CRITICAL_EFFECT(5);
private final int id;
NPCAnimation(int id) {
this.id = id;
}
public int getId() {
return id;
}
}
enum NPCStatus {
HURT(2), DIE(3);
private final int id;
NPCStatus(int id) {
this.id = id;
}
public int getId() {
return id;
}
}
public static class Action {
private boolean on_fire, crouched, sprinting, invisible, glowing, flying_elytra;
private byte result = 0;
public Action(boolean on_fire, boolean crouched, boolean sprinting, boolean invisible, boolean glowing,
boolean flying_elytra) {
this.on_fire = on_fire;
this.crouched = crouched;
this.sprinting = sprinting;
this.invisible = invisible;
this.glowing = glowing;
this.flying_elytra = flying_elytra;
}
public Action() {
}
public boolean isOn_fire() {
return on_fire;
}
public Action setOn_fire(boolean on_fire) {
this.on_fire = on_fire;
return this;
}
public boolean isCrouched() {
return crouched;
}
public Action setCrouched(boolean crouched) {
this.crouched = crouched;
return this;
}
public boolean isSprinting() {
return sprinting;
}
public Action setSprinting(boolean sprinting) {
this.sprinting = sprinting;
return this;
}
public boolean isInvisible() {
return invisible;
}
public Action setInvisible(boolean invisible) {
this.invisible = invisible;
return this;
}
public boolean isGlowing() {
return glowing;
}
public Action setGlowing(boolean glowing) {
this.glowing = glowing;
return this;
}
public boolean isFlying_elytra() {
return flying_elytra;
}
public Action setFlying_elytra(boolean flying_elytra) {
this.flying_elytra = flying_elytra;
return this;
}
public byte build() {
result = 0;
result = add(this.on_fire, (byte) 0x01);
result = add(this.crouched, (byte) 0x02);
result = add(this.sprinting, (byte) 0x08);
result = add(this.invisible, (byte) 0x20);
result = add(this.glowing, (byte) 0x40);
result = add(this.flying_elytra, (byte) 0x80);
return result;
}
private byte add(boolean condition, byte amount) {
return result += (condition ? amount : 0x00);
}
}
}
我需要这个 class 可序列化（最好使用 Gson）以在服务器关闭时保存实体。
目前我正在这样做：
Gson gson = new Gson();
for (NPC npc : npcs) {
System.out.println(gson.toJson(npc));
}
我遇到堆栈溢出：
java.lang.WhosebugError: null
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:383) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:378) ~[patched_1.16.1.jar:git-Paper-44]
最后两行重复了很多次，直到出现：
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:158) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.Gson.getAdapter(Gson.java:423) ~[patched_1.16.1.jar:git-Paper-44]
这些行也重复。
打印语句没有输出，NPC实例完好无损，我可以查询他们的字段。
我想 Gson 不能正确序列化 class 因为字段不是本地的并且递归调用一些东西直到堆栈被破坏。
有人可以帮我解决这个问题吗？ :)
这可能是由不可序列化的字段之一引起的。继续将每个对象标记为瞬态，直到您可以成功序列化该对象，然后您就知道哪个是罪魁祸首了。
如果一个对象 A 引用了一个对象 B，它也引用了 A，就会发生这种情况。作为使用 minecraft 实体的示例，它看起来像：
PlayerA 有一个引用 Creeper1 的 currentTarget 字段，Creeper1 有一个 Player 类型的 lastDamageBy 字段引用 PlayerA。在这种情况下，序列化 Creeper1 将尝试序列化 PlayerA，后者又会尝试通过它的 currentTarget 字段再次序列化 Creeper1。最终这将导致 WhosebugException.
在您的字段中的某处寻找这种循环引用。否则，您可以在 GSON 代码中放置一个断点并检查导致错误的确切字段。
一旦找到罪魁祸首，您可以删除该循环依赖性，或者使用 transient 关键字或 Exclusion Strategy 来定义如何或是否 deserialize/serialize 这些字段。
我目前正在为 Minecraft 中的 Spigot 插件编写自己的 NPC class。
import com.mojang.authlib.GameProfile;
import com.mojang.authlib.properties.Property;
import net.minecraft.server.v1_16_R1.*;
import org.bukkit.Bukkit;
import org.bukkit.Location;
import org.bukkit.craftbukkit.v1_16_R1.CraftServer;
import org.bukkit.craftbukkit.v1_16_R1.CraftWorld;
import org.bukkit.craftbukkit.v1_16_R1.entity.CraftPlayer;
import org.bukkit.craftbukkit.v1_16_R1.util.CraftChatMessage;
import org.bukkit.entity.Player;
import org.bukkit.plugin.Plugin;
import org.bukkit.scheduler.BukkitRunnable;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class NPC extends EntityPlayer implements Serializable {
private final int entityId;
private Location location;
private GameProfile gameprofile;
private final List<Player> recipients;
private Recipient recipient_type;
private String display_name;
private String tablist_name;
private final DataWatcher dataWatcher;
private final DataWatcherObject<Byte> object_entity_state;
private final DataWatcherObject<String> object_customName;
private final DataWatcherObject<Boolean> object_isSilent;
private final DataWatcherObject<Boolean> object_hasGravity;
private final DataWatcherObject<Boolean> object_isCustomNameVisible;
private boolean isDestroyed;
private final Plugin plugin;
public NPC(String name, Location location, UUID uuid, WorldServer worldServer, Plugin plugin) {
super(((CraftServer) Bukkit.getServer()).getServer(), worldServer, new GameProfile(uuid, name), new PlayerInteractManager(worldServer));
this.plugin = plugin;
this.display_name = name;
this.tablist_name = name;
this.recipient_type = Recipient.ALL;
this.recipients = new ArrayList<>();
this.entityId = (int) Math.ceil(Math.random() * 1000);
this.gameprofile = new GameProfile(uuid, display_name);
this.location = location;
this.dataWatcher = new DataWatcher(null);
this.dataWatcher.register(object_entity_state = new DataWatcherObject<>(0, DataWatcherRegistry.a), (byte) 0);
this.dataWatcher.register(new DataWatcherObject<>(1, DataWatcherRegistry.b), 300);
this.dataWatcher.register(object_customName = new DataWatcherObject<>(2, DataWatcherRegistry.d), "");
this.dataWatcher.register(object_isCustomNameVisible = new DataWatcherObject<>(3, DataWatcherRegistry.i),false);
this.dataWatcher.register(object_isSilent = new DataWatcherObject<>(4, DataWatcherRegistry.i), false);
this.dataWatcher.register(object_hasGravity = new DataWatcherObject<>(5, DataWatcherRegistry.i), false);
this.dataWatcher.register(new DataWatcherObject<>(9, DataWatcherRegistry.i), false);
this.dataWatcher.register(new DataWatcherObject<>(6, DataWatcherRegistry.a), (byte) 0);
this.dataWatcher.register(new DataWatcherObject<>(7, DataWatcherRegistry.c), 20.0F);
this.dataWatcher.register(new DataWatcherObject<>(8, DataWatcherRegistry.b), 0);
this.dataWatcher.register(new DataWatcherObject<>(10, DataWatcherRegistry.b), 0);
this.dataWatcher.register(new DataWatcherObject<>(11, DataWatcherRegistry.c), 0.0F);
this.dataWatcher.register(new DataWatcherObject<>(12, DataWatcherRegistry.b), 20);
this.dataWatcher.register(new DataWatcherObject<>(13, DataWatcherRegistry.a), (byte) 127);
this.dataWatcher.register(new DataWatcherObject<>(14, DataWatcherRegistry.a), (byte) 1);
this.dataWatcher.register(new DataWatcherObject<>(15, DataWatcherRegistry.p), new NBTTagCompound());
this.dataWatcher.register(new DataWatcherObject<>(16, DataWatcherRegistry.p), new NBTTagCompound());
}
public NPC(String name, Location location, Plugin plugin) {
this(name, location, UUID.randomUUID(), ((CraftWorld) Bukkit.getWorlds().get(0)).getHandle(), plugin);
}
public NPC(String name, Location location, UUID uuid, Plugin plugin) {
this(name, location, uuid, ((CraftWorld) Bukkit.getWorlds().get(0)).getHandle(), plugin);
}
// public Map<String, Object> serialize() {
// Map<String, Object> result = new HashMap<>();
// BeanInfo info = null;
// try {
// info = Introspector.getBeanInfo(this.getClass());
// } catch (IntrospectionException e) {
// e.printStackTrace();
// }
// for (PropertyDescriptor pd : info.getPropertyDescriptors()) {
// Method reader = pd.getReadMethod();
// if (reader != null) {
// try {
// result.put(pd.getName(), reader.invoke(this));
// } catch (IllegalAccessException | InvocationTargetException e) {
// e.printStackTrace();
// }
// }
// }
// return result;
// }
/*
* view all the packet receivers
*/
public List<Player> getRecipients() {
return this.recipients;
}
/*
* get the signature and skin from the gameprofile
*/
public Property getSkin() {
if (this.gameprofile.getProperties().isEmpty())
return null;
return (Property) this.gameprofile.getProperties().get("textures").toArray()[0];
}
/*
* get npc id
*/
public int getEntityId() {
return entityId;
}
/*
* get npc location
*/
public Location getLocation() {
return location;
}
/*
* get npc gameprofile
*/
public GameProfile getGameprofile() {
return gameprofile;
}
/*
* get all the packet receivers
*/
public Recipient getRecipient_type() {
return recipient_type;
}
/*
* get npc displayname above head
*/
public String getDisplay_name() {
return display_name;
}
/*
* get npc displayname in tablist
*/
public String getTablist_name() {
return tablist_name;
}
/*
* check if npc is deleted
*/
public boolean isDestroyed() {
return isDestroyed;
}
/*
* get plugin
*/
public Plugin getPlugin() {
return plugin;
}
/*
* add Player so it receives the update packets
*/
public void addRecipient(Player p) {
this.recipients.add(p);
}
/*
* Remove Player that receives the update packets
*/
public void removeRecipient(Player p) {
this.recipients.remove(p);
}
/*
* toggle if the packet receivers are all the players online or a specicif group.
* If set to ALL (online) then the set/get recipient will have no effect
*/
public void setRecipientType(Recipient recipient_type) {
this.recipient_type = recipient_type;
}
/*
* spawn the npc, this should be the last function after init.
*/
public void spawn(boolean tablist, boolean fix_head) {
PacketPlayOutNamedEntitySpawn packet = new PacketPlayOutNamedEntitySpawn();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", this.gameprofile.getId());
this.setField(packet, "c", location.getX());
this.setField(packet, "d", location.getY());
this.setField(packet, "e", location.getZ());
this.setField(packet, "f", fix_head ? (byte) ((int) location.getYaw() * 256.0F / 360.0F) : 0);
this.setField(packet, "g", fix_head ? (byte) ((int) location.getPitch() * 256.0F / 360.0F) : 0);
// this.setField(packet, "i", this.dataWatcher);
this.addToTabList();
this.sendPacket(packet);
this.isDestroyed = false;
//Delay is required to commit the tablist changes
new BukkitRunnable() {
@Override
public void run() {
if (!tablist) removeFromTabList();
}
}.runTaskLater(this.plugin, 5);
}
/*
* put items in inventory, see https://www.google.nl/search?q=bukkit+inventory+slots&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjr9v_FxvjaAhUFMuwKHQi7ALUQ_AUICigB&biw=1920&bih=974#imgrc=QUECAbUohgZxbM:
* for more info
*/
public void setEquipment(EnumItemSlot slot, ItemStack item) {
PacketPlayOutEntityEquipment packet = new PacketPlayOutEntityEquipment();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", slot);
this.setField(packet, "c", item);
this.sendPacket(packet);
}
/*
* set the name above the player
*/
public void setDisplayNameAboveHead(String name) throws IOException {
if(name.length() > 16) throw new IOException("Name cannot be longer than 16 chatacters.");
this.display_name = name;
this.reloadNpc();
}
/*
* set the name above the player and tablist.
*/
public void setDisplayName(String name) throws IOException {
this.setDisplayNameAboveHead(name);
this.setTablistName(name);
}
/*
* set custom name in tablist
*/
public void setTablistName(String name) {
this.tablist_name = name;
this.updateToTabList();
}
/*
* respawn the npc and refresh all comitted changes
*/
public void reloadNpc() {
this.updateProfile();
if(!this.isDestroyed) {
PacketPlayOutEntityDestroy packet = new PacketPlayOutEntityDestroy(this.entityId);
this.sendPacket(packet);
this.spawn(true, true);
}
}
/*
* Update/Refresh the gameprofile that contains UUID, Name, Skin.
*/
private void updateProfile() {
Property skin = this.getSkin();
this.gameprofile = new GameProfile(this.gameprofile.getId(), this.display_name);
if (skin != null)
this.setSkin(skin.getValue(), skin.getSignature());
}
/*
* set the texture and signature in the gameprofile, to submit it you must reload player.
*/
public void setSkin(String texture, String signature) {
this.gameprofile.getProperties().put("textures", new Property("textures", texture, signature));
}
/*
* remove npc from the recipient's tablist
*/
public void removeFromTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.REMOVE_PLAYER);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* update npc to the recipient's tablist
*/
public void updateToTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.UPDATE_DISPLAY_NAME);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* add npc from the recipient's tablist
*/
public void addToTabList() {
PacketPlayOutPlayerInfo packet = new PacketPlayOutPlayerInfo();
PacketPlayOutPlayerInfo.PlayerInfoData data = packet.new PlayerInfoData(this.gameprofile, 0,
EnumGamemode.NOT_SET, CraftChatMessage.fromString(tablist_name)[0]);
List<PacketPlayOutPlayerInfo.PlayerInfoData> players = (List<PacketPlayOutPlayerInfo.PlayerInfoData>) getField(packet, "b");
players.add(data);
this.setField(packet, "a", PacketPlayOutPlayerInfo.EnumPlayerInfoAction.ADD_PLAYER);
this.setField(packet, "b", players);
this.sendPacket(packet);
}
/*
* set player action, such as shift, onfire, ect recommending to use 'public void setAction(Action action)'.
*/
public void setAction(byte action) {
this.setMetaData(action);
}
/*
* set player action, such as shift, onfire, ect.
*/
public void setAction(Action action) {
this.setMetaData(action.build());
}
/*
* make sure the npc is near a bed or on it.
*/
// public void setSleep(boolean state) {
// if (state) {
// Location bed = new Location(this.location.getWorld(), 0, 0, 0);
// PacketPlayOutBed packet = new PacketPlayOutBed();
// this.setField(packet, "a", this.entityId);
// this.setField(packet, "b", new BlockPosition(bed.getX(), bed.getY(), bed.getZ()));
//
// for (Player p : (this.recipient_type == Recipient.ALL ? Bukkit.getOnlinePlayers() : this.recipients)) {
// ((CraftPlayer) p).sendBlockChange(bed, Material.BED_BLOCK, (byte) 0);
// ((CraftPlayer) p).sendBlockChange(bed.add(0, 0, 1), Material.BED_BLOCK, (byte) 2);
// }
//
// this.sendPacket(packet);
// this.teleport(location.clone().add(0, 0.3, 0), false);
//
// } else {
// this.setAnimation(NPCAnimation.LEAVE_BED);
// this.teleport(location.clone().subtract(0, 0.3, 0), true);
// }
// }
/*
* delete the npc from the server.
*/
public void destroy() {
PacketPlayOutEntityDestroy packet = new PacketPlayOutEntityDestroy(this.entityId);
this.removeFromTabList();
this.sendPacket(packet);
this.isDestroyed = true;
}
/*
* set npc status such as die or hurt. I recommond to use method 'public void setStatus(NPCStatus status)'
*/
public void setStatus(byte status) {
PacketPlayOutEntityStatus packet = new PacketPlayOutEntityStatus();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", status);
this.sendPacket(packet);
}
/*
* set npc status such as die or hurt.
*/
public void setStatus(NPCStatus status) {
this.setStatus((byte) status.getId());
}
/*
* set npc effect such as Night Vision or something else.
*/
public void setEffect(MobEffect effect) {
this.sendPacket(new PacketPlayOutEntityEffect(this.entityId, effect));
}
/*
* set npc animation such as Swing arm ect. I recommend using method 'public void setAnimation(NPCAnimation animation)'
*/
public void setAnimation(byte animation) {
PacketPlayOutAnimation packet = new PacketPlayOutAnimation();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", animation);
this.sendPacket(packet);
}
/*
* set npc animation such as Swing arm ect.
*/
public void setAnimation(NPCAnimation animation) {
this.setAnimation((byte) animation.getId());
}
/*
* teleport npc to different location
*/
public void teleport(Location location, Boolean onGround) {
PacketPlayOutEntityTeleport packet = new PacketPlayOutEntityTeleport();
this.setField(packet, "a", this.entityId);
this.setField(packet, "b", location.getX());
this.setField(packet, "c", location.getY());
this.setField(packet, "d", location.getZ());
this.setField(packet, "e", (byte) location.getYaw());
this.setField(packet, "f", (byte) location.getPitch());
this.setField(packet, "g", onGround);
this.sendPacket(packet);
this.rotateHead(location.getPitch(), location.getYaw());
this.location = location;
}
/*
* rotate npc head to pitch and yaw.
*/
public void rotateHead(float pitch, float yaw) {
PacketPlayOutEntity.PacketPlayOutEntityLook packet = new PacketPlayOutEntity.PacketPlayOutEntityLook(this.entityId, getFixRotation(yaw), (byte) pitch, true);
PacketPlayOutEntityHeadRotation packet_1 = new PacketPlayOutEntityHeadRotation();
this.setField(packet_1, "a", this.entityId);
this.setField(packet_1, "b", getFixRotation(yaw));
this.sendPacket(packet);
this.sendPacket(packet_1);
}
/*
* These methods below are not usefull.
*/
private <T> void setDataWatcherObject(DataWatcherObject<T> datawatcherobject, Object t0) {
try {
Method m = this.dataWatcher.getClass().getDeclaredMethod("registerObject", DataWatcherObject.class,
Object.class);
m.setAccessible(true);
m.invoke(this.dataWatcher, datawatcherobject, t0);
} catch (Exception e) {
e.printStackTrace();
}
}
private void setMetaData(byte data) {
this.setDataWatcherObject(this.object_entity_state, data);
PacketPlayOutEntityMetadata packet = new PacketPlayOutEntityMetadata(this.entityId, this.dataWatcher, true);
sendPacket(packet);
}
private byte getFixRotation(float yawpitch) {
return (byte) ((int) (this.location.getYaw() * 256.0F / 360.0F));
}
private Object getField(Object obj, String field_name) {
try {
Field field = obj.getClass().getDeclaredField(field_name);
field.setAccessible(true);
return field.get(obj);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private void setField(Object obj, String field_name, Object value) {
try {
Field field = obj.getClass().getDeclaredField(field_name);
field.setAccessible(true);
field.set(obj, value);
} catch (Exception e) {
e.printStackTrace();
}
}
private void sendPacket(Packet<?> packet, Player player) {
((CraftPlayer) player).getHandle().playerConnection.sendPacket(packet);
}
private void sendPacket(Packet<?> packet) {
for (Player p : (this.recipient_type == Recipient.ALL ? Bukkit.getOnlinePlayers() : this.recipients)) {
this.sendPacket(packet, p);
}
}
enum Recipient {
ALL, LISTED_RECIPIENTS
}
enum NPCAnimation {
SWING_MAIN_HAND(0),
TAKE_DAMAGE(1),
LEAVE_BED(2),
SWING_OFFHAND(3),
CRITICAL_EFFECT(4),
MAGIC_CRITICAL_EFFECT(5);
private final int id;
NPCAnimation(int id) {
this.id = id;
}
public int getId() {
return id;
}
}
enum NPCStatus {
HURT(2), DIE(3);
private final int id;
NPCStatus(int id) {
this.id = id;
}
public int getId() {
return id;
}
}
public static class Action {
private boolean on_fire, crouched, sprinting, invisible, glowing, flying_elytra;
private byte result = 0;
public Action(boolean on_fire, boolean crouched, boolean sprinting, boolean invisible, boolean glowing,
boolean flying_elytra) {
this.on_fire = on_fire;
this.crouched = crouched;
this.sprinting = sprinting;
this.invisible = invisible;
this.glowing = glowing;
this.flying_elytra = flying_elytra;
}
public Action() {
}
public boolean isOn_fire() {
return on_fire;
}
public Action setOn_fire(boolean on_fire) {
this.on_fire = on_fire;
return this;
}
public boolean isCrouched() {
return crouched;
}
public Action setCrouched(boolean crouched) {
this.crouched = crouched;
return this;
}
public boolean isSprinting() {
return sprinting;
}
public Action setSprinting(boolean sprinting) {
this.sprinting = sprinting;
return this;
}
public boolean isInvisible() {
return invisible;
}
public Action setInvisible(boolean invisible) {
this.invisible = invisible;
return this;
}
public boolean isGlowing() {
return glowing;
}
public Action setGlowing(boolean glowing) {
this.glowing = glowing;
return this;
}
public boolean isFlying_elytra() {
return flying_elytra;
}
public Action setFlying_elytra(boolean flying_elytra) {
this.flying_elytra = flying_elytra;
return this;
}
public byte build() {
result = 0;
result = add(this.on_fire, (byte) 0x01);
result = add(this.crouched, (byte) 0x02);
result = add(this.sprinting, (byte) 0x08);
result = add(this.invisible, (byte) 0x20);
result = add(this.glowing, (byte) 0x40);
result = add(this.flying_elytra, (byte) 0x80);
return result;
}
private byte add(boolean condition, byte amount) {
return result += (condition ? amount : 0x00);
}
}
}
我需要这个 class 可序列化（最好使用 Gson）以在服务器关闭时保存实体。 目前我正在这样做：
Gson gson = new Gson();
for (NPC npc : npcs) {
System.out.println(gson.toJson(npc));
}
我遇到堆栈溢出：
java.lang.WhosebugError: null
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:383) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:378) ~[patched_1.16.1.jar:git-Paper-44]
最后两行重复了很多次，直到出现：
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:158) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100) ~[patched_1.16.1.jar:git-Paper-44]
at com.google.gson.Gson.getAdapter(Gson.java:423) ~[patched_1.16.1.jar:git-Paper-44]
这些行也重复。 打印语句没有输出，NPC实例完好无损，我可以查询他们的字段。
我想 Gson 不能正确序列化 class 因为字段不是本地的并且递归调用一些东西直到堆栈被破坏。
有人可以帮我解决这个问题吗？ :)
这可能是由不可序列化的字段之一引起的。继续将每个对象标记为瞬态，直到您可以成功序列化该对象，然后您就知道哪个是罪魁祸首了。
如果一个对象 A 引用了一个对象 B，它也引用了 A，就会发生这种情况。作为使用 minecraft 实体的示例，它看起来像：
PlayerA 有一个引用 Creeper1 的 currentTarget 字段，Creeper1 有一个 Player 类型的 lastDamageBy 字段引用 PlayerA。在这种情况下，序列化 Creeper1 将尝试序列化 PlayerA，后者又会尝试通过它的 currentTarget 字段再次序列化 Creeper1。最终这将导致 WhosebugException.
在您的字段中的某处寻找这种循环引用。否则，您可以在 GSON 代码中放置一个断点并检查导致错误的确切字段。
一旦找到罪魁祸首，您可以删除该循环依赖性，或者使用 transient 关键字或 Exclusion Strategy 来定义如何或是否 deserialize/serialize 这些字段。