当我通过反射调用无参数构造函数时,它会抛出 NoClassDefError。 我确信 bukkit 加载了我项目的所有类,因为当使用 Class.forName(String) 调用类时它不会抛出异常。
如何使用此代码解析 ClassNotFound?
我使用了这段代码:
ClassPool pool = ClassPool.getDefault();
pool.insertClassPath(new ClassClassPath(ReflectedNBTCompound.class));
CtClass cl = pool.getCtClass(ReflectedNBTWrapper.class.getCanonicalName());
CtClass ct = pool.makeClass("NBTCompatibleTileEntity", ctClass);
ct.addField(new CtField(cl, "nbtField", ct));
ct.addConstructor(CtNewConstructor.make(
"public NBTCompatibleTileEntity(){" +
" this.nbtField = new skywolf46.NBTUtil.v1_3.NBTData.ReflectedNBTCompound();" +
"System.out.println(\"Object created!\");" +
"}"
, ct
));
ct.addMethod(CtMethod.make(
"public skywolf46.NBTUtil.v1_3.NBTData.ReflectedNBTCompound getNBT(){" +
" return nbtField;" +
"}"
, ct));
ct.addMethod(CtMethod.make(
"public void load(" + BukkitVersionUtil.getNMSClass("NBTTagCompound").getName() + " comp){" +
" if(comp.hasKey(\"ReflectedNBT\"))" +
" nbtField = new skywolf46.NBTUtil.v1_3.NBTData.ReflectedNBTCompound(comp.getCompound(\"ReflectedNBT\"));" +
"}"
, ct));
Class c = ct.toClass();
c.getConstructor().newInstance();
Bukkit.getConsoleSender().sendMessage("§5ReflectedNBTWrapper §7| §aInitialized! ");
错误:
java.lang.NoClassDefFoundError: skywolf46/NBTUtil/v1_3/NBTData/ReflectedNBTCompound
at java.lang.Class.getDeclaredConstructors0(Native Method) ~[?:1.8.0_202]
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2671) ~[?:1.8.0_202]
at java.lang.Class.getConstructor0(Class.java:3075) ~[?:1.8.0_202]
at java.lang.Class.getConstructor(Class.java:1825) ~[?:1.8.0_202]
at skywolf46.NBTUtil.v1_3.ReflectedNBTWrapper.initBukkit(ReflectedNBTWrapper.java:88) ~[?:?]
at skywolf46.NBTUtil.v1_3.ReflectedNBTWrapper.onEnable(ReflectedNBTWrapper.java:27) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264) ~[spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:403) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugin(CraftServer.java:381) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugins(CraftServer.java:330) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at net.minecraft.server.v1_12_R1.MinecraftServer.t(MinecraftServer.java:422) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:383) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:338) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:545) [spigot-ram-patched.jar:git-Spigot-79a30d7-acbc348]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_202]
Caused by: java.lang.ClassNotFoundException: skywolf46.NBTUtil.v1_3.NBTData.ReflectedNBTCompound
at java.net.URLClassLoader.findClass(URLClassLoader.java:382) ~[?:1.8.0_202]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_202]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[?:1.8.0_202]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_202]
最佳答案
您可能在错误的类加载器中定义了此类,在 bukkit 中,每个插件都位于单独的类加载器中,并且 .toClass()
使用线程上下文类加载器,该类加载器可能设置为某个不同的类加载器.
因此,当加载新类时,它会尝试从插件中查找其他类,但会失败,因为无法从此类加载器访问它们。
尝试使用
Class c = ct.toClass(ReflectedNBTCompound.class)
或
Class c = ct.toClass(MyPlugin.class.getClassLoader())
关于Javassist CtClass 可以工作,但在调用构造函数时抛出 NoClassDefError,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60472956/