Java 使用newInstance()实例化类时出现NoSuchMethodException
我使用以下代码实例化包中的每个类:Java 使用newInstance()实例化类时出现NoSuchMethodException,java,bukkit,Java,Bukkit,我使用以下代码实例化包中的每个类: for (Class listenerClass : ClassGetter.getClassesForPackage(this, "cullan.listener")) { Bukkit.getLogger().info(listenerClass.getSimpleName()); if (!listenerClass.getSimpleName().equals("EnchantmentListener")
for (Class listenerClass : ClassGetter.getClassesForPackage(this, "cullan.listener")) {
Bukkit.getLogger().info(listenerClass.getSimpleName());
if (!listenerClass.getSimpleName().equals("EnchantmentListener")) {
try {
listenerClass.newInstance();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
这工作得非常好,但是,当其中一个类被实例化时,我遇到了这个错误:
[07:07:58] [Server thread/WARN]: java.lang.InstantiationException: cullan.listener.AgilityListener$1
[07:07:58] [Server thread/WARN]: at java.lang.Class.newInstance(Unknown Source)
[07:07:58] [Server thread/WARN]: at cullan.main.DCEnchants.loadEnchants(DCEnchants.java:62)
[07:07:58] [Server thread/WARN]: at cullan.main.DCEnchants.onEnable(DCEnchants.java:24)
[07:07:58] [Server thread/WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321)
[07:07:58] [Server thread/WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340)
[07:07:58] [Server thread/WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405)
[07:07:58] [Server thread/WARN]: at net.skycraftmc.PluginManager.PluginManagerPlugin.onCommand(PluginManagerPlugin.java:287)
[07:07:58] [Server thread/WARN]: at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
[07:07:58] [Server thread/WARN]: at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141)
[07:07:58] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:646)
[07:07:58] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:632)
[07:07:58] [Server thread/WARN]: at net.minecraft.server.v1_8_R3.DedicatedServer.aO(DedicatedServer.java:409)
[07:07:58] [Server thread/WARN]: at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:373)
[07:07:58] [Server thread/WARN]: at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:709)
[07:07:58] [Server thread/WARN]: at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:612)
[07:07:58] [Server thread/WARN]: at java.lang.Thread.run(Unknown Source)
[07:07:58] [Server thread/WARN]: Caused by: java.lang.NoSuchMethodException: cullan.listener.AgilityListener$1.<init>()
[07:07:58] [Server thread/WARN]: at java.lang.Class.getConstructor0(Unknown Source)
[07:07:58][Server-thread/WARN]:java.lang.InstantiationException:cullan.listener.AgilityListener$1
[07:07:58][Server thread/WARN]:位于java.lang.Class.newInstance(未知源)
[07:07:58][Server thread/WARN]:在cullan.main.DCEnchants.loadEnchants(DCEnchants.java:62)
[07:07:58][Server thread/WARN]:在cullan.main.DCEnchants.onEnable(DCEnchants.java:24)
[07:07:58][Server thread/WARN]:位于org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321)
[07:07:58][Server thread/WARN]:位于org.bukkit.plugin.java.javapluginload.enablePlugin(javapluginload.java:340)
[07:07:58][Server thread/WARN]:位于org.bukkit.plugin.SimplePluginManager.enablepluginmanager(SimplePluginManager.java:405)
[07:07:58][Server thread/WARN]:在net.skycraftmc.PluginManager.PluginManagerPlugin.onCommand(PluginManagerPlugin.java:287)
[07:07:58][Server thread/WARN]:位于org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
[07:07:58][Server thread/WARN]:位于org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141)
[07:07:58][Server thread/WARN]:位于org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:646)
[07:07:58][Server thread/WARN]:位于org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:632)
[07:07:58][Server-thread/WARN]:在net.minecraft.Server.v1_8_R3.dicatedserver.aO(dicatedserver.java:409)
[07:07:58][Server thread/WARN]:在net.minecraft.Server.v1_8_R3.dicatedserver.B(dicatedserver.java:373)
[07:07:58][Server thread/WARN]:位于net.minecraft.Server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:709)
[07:07:58][Server thread/WARN]:在net.minecraft.Server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:612)
[07:07:58][Server thread/WARN]:位于java.lang.thread.run(未知源)
[07:07:58][Server thread/WARN]:原因:java.lang.NoSuchMethodException:cullan.listener.AgilityListener$1。()
[07:07:58][Server thread/WARN]:位于java.lang.Class.getConstructor0(未知源)
这是引发错误的类:
package cullan.listener;
import cullan.type.EnchantmentRarity;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.player.PlayerQuitEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.potion.PotionEffect;
import java.util.ArrayList;
import java.util.List;
public class AgilityListener extends EnchantmentListener{
private List<Player> players = new ArrayList<>();
public AgilityListener() {
super(Enchantment.getByName("Agility"), EnchantmentRarity.VERY_RARE);
startTimer();
}
@EventHandler
public void onQuit(PlayerQuitEvent event) {
Player player = event.getPlayer();
if (players.contains(player)) {
players.remove(player);
}
}
private void startTimer() {
final PotionEffect effect = mainConfig.getAgilityEffect();
instance.getServer().getScheduler().scheduleSyncRepeatingTask(instance, new Runnable() {
@Override
public void run() {
for (Player player : instance.getServer().getOnlinePlayers()) {
ItemStack boots = player.getInventory().getBoots();
if (boots != null && boots.containsEnchantment(enchantment)) {
player.addPotionEffect(effect);
players.add(player);
} else if (players.contains(player)) {
player.removePotionEffect(effect.getType());
players.remove(player);
}
}
}
}, 10L, 10L);
}
}
包cullan.listener;
导入cullan.type.enchanmentrarity;
导入org.bukkit.enchanments.enchanment;
导入org.bukkit.entity.Player;
导入org.bukkit.event.EventHandler;
导入org.bukkit.event.player.PlayerQuitEvent;
导入org.bukkit.inventory.ItemStack;
导入org.bukkit.potion.PotionEffect;
导入java.util.ArrayList;
导入java.util.List;
公共类AgilityListener扩展了EnchantmentListener{
private List players=new ArrayList();
公共AgilityListener(){
超级(附魔,敏捷),附魔稀有,非常罕见);
startTimer();
}
@事件处理程序
public void onQuit(PlayerQuitEvent事件){
Player=event.getPlayer();
if(player.contains(player)){
玩家。移除(玩家);
}
}
私有void startTimer(){
最终PotioneEffect effect=mainConfig.getAgilityEffect();
instance.getServer().getScheduler().scheduleSyncRepeatingTask(实例,新的Runnable()){
@凌驾
公开募捐{
对于(Player-Player:instance.getServer().getOnlinePlayers()){
ItemStack boots=player.getInventory().getBoots();
if(boots!=null&&boots.containsenchant(附魔)){
玩家。添加药剂效果(效果);
players.add(player);
}else if(players.contains(player)){
player.removePotionEffect(effect.getType());
玩家。移除(玩家);
}
}
}
},10L,10L);
}
}
如果删除startTimer()方法,则不会发生此错误。为什么会发生这种情况?问题在于您没有试图构造
AgilityListener
的实例-您正在尝试构造在AgilityListener.startTimer
中创建的匿名内部类的实例。这就是为什么堆栈跟踪具有:
Caused by: java.lang.NoSuchMethodException: cullan.listener.AgilityListener$1.<init>()
或:
等等。您还可以检查该类是否具有公共无参数构造函数,以及它是否可分配给
EnchantmentListener
您的问题是什么?你是在问为什么会这样吗?@SotiriosDelimanolis是的
if (!listenerClass.getSimpleName().equals("EnchantmentListener") &&
!listenerClass.getSimpleName().contains("$"))
!listenerClass.isAnonymousClass()