检查附魔时的 Bukkit Nullpointer

Question

每当我使用 Bukkit 的 "containsEnchantment()" 方法时，我都会收到 nullpointerexception，据推测，该方法 returns 是一个布尔值。此代码段的目的是检查玩家物品栏中的物品是否具有高于 5 的附魔。

我的日志显示在第 408 行抛出了空指针异常。在我的代码中，我在第 408 行留下了注释。

我试着用其他方法来检查物品是否有附魔；但是，每当我使用 "getEnchantments()." 我在 Eclipse 中编译和导出我的插件时都会出现导出错误，然后使用 jd-GUI 对其进行反编译以检查是否损坏。当我使用 getEnchantments() 时：java.util.Map，当我反编译我的 .jar 时，jd-GUI 显示 //INTERNAL ERROR//。使用地图不适用于 Bukkit。

我不明白为什么我的代码不起作用。变量 "player" 是类型 org.Bukkit.entity.Player.

这是我的一些代码：

       boolean illegalEnchants = false;
         ArrayList<ItemStack> stacks = new ArrayList<ItemStack>();
        Inventory i = player.getInventory();
                      if(i.getContents() != null){
                          for(ItemStack inven : i.getContents()){

                            ArrayList<Integer> enchants = new ArrayList<Integer>();

                                if(inven.containsEnchantment(Enchantment.ARROW_DAMAGE)){ //LINE 408
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.ARROW_DAMAGE));
                                }
                                if(inven.containsEnchantment(Enchantment.ARROW_FIRE)){
                                enchants.add(inven.getEnchantmentLevel(Enchantment.ARROW_FIRE));
                                }
                                if(inven.containsEnchantment(Enchantment.ARROW_INFINITE)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.ARROW_INFINITE));
                                    }
                                if(inven.containsEnchantment(Enchantment.ARROW_KNOCKBACK)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.ARROW_KNOCKBACK));
                                }
                                if(inven.containsEnchantment(Enchantment.DAMAGE_ALL)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.DAMAGE_ALL));
                                }
                                if(inven.containsEnchantment(Enchantment.DAMAGE_ARTHROPODS)){
                                enchants.add(inven.getEnchantmentLevel(Enchantment.DAMAGE_ARTHROPODS));
                                }
                                if(inven.containsEnchantment(Enchantment.DAMAGE_UNDEAD)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.DAMAGE_UNDEAD));
                                }
                                if(inven.containsEnchantment(Enchantment.DEPTH_STRIDER)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.DEPTH_STRIDER));
                                }
                                if(inven.containsEnchantment(Enchantment.DIG_SPEED)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.DIG_SPEED));
                                }
                                if(inven.containsEnchantment(Enchantment.DURABILITY)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.DURABILITY));
                                }

                                if(inven.containsEnchantment(Enchantment.FIRE_ASPECT)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.FIRE_ASPECT));
                                }
                                if(inven.containsEnchantment(Enchantment.KNOCKBACK)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.KNOCKBACK));
                                }
                                if(inven.containsEnchantment(Enchantment.LOOT_BONUS_BLOCKS)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.LOOT_BONUS_BLOCKS));
                                }
                                if(inven.containsEnchantment(Enchantment.LOOT_BONUS_MOBS)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.LOOT_BONUS_MOBS));
                                }
                                if(inven.containsEnchantment(Enchantment.LUCK)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.LUCK));
                                }
                                if(inven.containsEnchantment(Enchantment.OXYGEN)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.OXYGEN));
                                }
                                if(inven.containsEnchantment(Enchantment.LURE)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.LURE));
                                }
                                if(inven.containsEnchantment(Enchantment.PROTECTION_ENVIRONMENTAL)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.PROTECTION_ENVIRONMENTAL));
                                }
                                if(inven.containsEnchantment(Enchantment.PROTECTION_EXPLOSIONS)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.PROTECTION_EXPLOSIONS));
                                }
                                if(inven.containsEnchantment(Enchantment.PROTECTION_FALL)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.PROTECTION_FALL));   
                                }
                                if(inven.containsEnchantment(Enchantment.PROTECTION_FIRE)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.PROTECTION_FIRE));
                                }
                                if(inven.containsEnchantmen(tEnchantment.PROTECTION_PROJECTILE)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.PROTECTION_PROJECTILE));
                                }
                                if(inven.containsEnchantment(Enchantment.SILK_TOUCH)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.SILK_TOUCH));    
                                }
                                if(inven.containsEnchantment(Enchantment.THORNS)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.THORNS));
                                }
                                if(inven.containsEnchantment(Enchantment.WATER_WORKER)){
                                    enchants.add(inven.getEnchantmentLevel(Enchantment.WATER_WORKER));
                                }


                                for(int j : enchants){
                                    if(j > 5){
                                        illegalEnchants = true;
                                            stacks.add(inven);
                                    }
                                }

                          }
                      }
for(ItemStack is : stacks){
i.removeItem(is);
}

这是我的服务器日志：

10.03 21:54:54 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at me.pyro.main.Main.onCommand(Main.java:408) ~[?:?] 10.03 21:54:54 [Server] INFO Caused by: java.lang.NullPointerException 10.03 21:54:54 [Server] INFO at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:536) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:628) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:335) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:672) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_45] 10.03 21:54:54 [Server] INFO at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.PlayerConnectionUtils.run(SourceFile:13) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(SourceFile:9) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(SourceFile:37) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:966) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1106) [craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:620) ~[craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:140) ~[craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[craftbukkit.jar:git-Bukkit-880a532] 10.03 21:54:54 [Server] INFO org.bukkit.command.CommandException: Unhandled exception executing command 'removeitems' in plugin AntiInventoryCheat v1.8 10.03 21:54:54 [Server] ERROR null

Answer 1

代码中的第 408 行（以及所有其他引用 inven 的行）可以抛出 NullPointerException，因为您正在遍历的清单中的 ItemStack 可以是 null 在空插槽的情况下。空检查将解决这个问题，例如：

for (ItemStack item : inventory.getContents()) {
    if (item == null) {
        continue;
    }
    // Your enchantment code here
}

Answer 2

int getEnchantmentLevel(Enchantment ench) Gets the level of the specified enchantment on this item stack

getEnchantmentLevel 正在返回一个 int，但您的数组列表是 Integer。难道是那个？

检查附魔时的 Bukkit Nullpointer

Bukkit Nullpointer when checking for enchantment

bukkit