Question

我已经花了很多时间对其进行故障排除，因为你可以看到所有的println's。所以我需要问一下。为什么blocks.add工作但label.add我得到错误null？

我的故障排除println返回＆＃34;添加标签[1]：强度＆＃34;所以我知道价值观在那里。

void load() {       
    String path = "menus.inventorys.stats";
    System.out.println("setting variables");
    // now load stat details from config
    System.out.println("default name");
    String defaultName = statConfig.getDefaults().getString(path + ".name");
    System.out.println("done");
    System.out.println("defaultslots");
    int defaultSlots = statConfig.getDefaults().getInt(path + ".slots");
    System.out.println("done");
    System.out.println("mame");
    name = statConfig.getString(path + ".name", defaultName);
    System.out.println("done");
    System.out.println("slots");
    slots = statConfig.getInt(path + ".slots", defaultSlots);
    System.out.println("done");

    InventoryController inventory = new InventoryController();
    ArrayList<Material> blocks = new ArrayList<>();
    ArrayList<String> labels = new ArrayList<>();
    ArrayList<String> slots = new ArrayList<>();

    if (statConfig.isSet(path + "slot")) {
        System.out.println("path to slots exists");
    }

    System.out.println("beginning loop");
    for (String slot : statConfig.getConfigurationSection(path + ".slot").getKeys(false)) {
        System.out.println("iterating material");
        Material block = (Material) statConfig.get(path + ".slot." + slot + ".block");
        System.out.println("material found");
        System.out.println("iterating label");
        String label = statConfig.getString(path + ".slot." + slot + ".label");
        System.out.println("label found");
        System.out.println("adding block");
        blocks.add(block);
        System.out.println("done");
        int blockSize = blocks.size();
        System.out.println("adding labels[" + blockSize + "]: " + label);
        labels.add(blockSize, label);
        System.out.println("done");
        System.out.println("adding slot");
        slots.add(blocks.size(), label);  // remember this is seperate from the arraylist for the block ItemStacks we will need to call this seperately
        System.out.println("done");
    }

[16:17:08] [服务器主题/信息]：完成 [16:17:08] [服务器主题/信息]：添加标签[1]：强度 [16:17:08] [服务器主题/信息]：完成 [16:17:08] [服务器线程/信息]：添加插槽 [16:17:08] [服务器线程/错误]：null org.bukkit.command.CommandException：未处理的异常执行命令＆＃39; rift＆＃39;在插件rift v0.0.1中在org.bukkit.command.PluginCommand.execute（PluginCommand.java:46）〜[插口1.8_server.jar：GIT-插口dbe012b-61ef214] 在org.bukkit.command.SimpleCommandMap.dispatch（SimpleCommandMap.java:141）〜[插口1.8_server.jar：GIT-插口dbe012b-61ef214] 在org.bukkit.craftbukkit.v1_8_R2.CraftServer.dispatchCommand（CraftServer.java:646）〜[插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.PlayerConnection.handleCommand（PlayerConnection.java:1133） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.PlayerConnection.a（PlayerConnection.java:968） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.PacketPlayInChat.a（PacketPlayInChat.java:45） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.PacketPlayInChat.a（PacketPlayInChat.java:1） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.PlayerConnectionUtils $ 1.run（SourceFile：13） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at java.util.concurrent.Executors $ RunnableAdapter.call（Unknown Source）[？：1.8.0_51] at java.util.concurrent.FutureTask.run（Unknown Source）[？：1.8.0_51] at net.minecraft.server.v1_8_R2.SystemUtils.a（SourceFile：60）[spigot-1.8_server.jar：git-Spigot-dbe012b-61ef214] at net.minecraft.server.v1_8_R2.MinecraftServer.A（MinecraftServer.java:710） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.DedicatedServer.A（DedicatedServer.java:368） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.MinecraftServer.z（MinecraftServer.java:651） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] at net.minecraft.server.v1_8_R2.MinecraftServer.run（MinecraftServer.java:554） [插口1.8_server.jar：GIT-插口dbe012b-61ef214] 在java.lang.Thread.run（未知来源）[？：1.8.0_51] 引起：java.lang.IndexOutOfBoundsException：索引：1，大小：0 at java.util.ArrayList.rangeCheckForAdd（Unknown Source）〜[？：1.8.0_51] 在java.util.ArrayList.add（未知来源）〜[？：1.8.0_51] 在com.au.mshcraft.rift.StatModel.load（StatController.java:201）〜[？：？] 在com.au.mshcraft.rift.StatController.open（StatController.java:52）〜[：？] 在com.au.mshcraft.rift.Rift.statView（Rift.java:100）〜[？：？] 在com.au.mshcraft.rift.Rift.onCommand（Rift.java:81）〜[？：？] 在org.bukkit.command.PluginCommand.execute（PluginCommand.java:44）〜[插口1.8_server.jar：GIT-插口dbe012b-61ef214] ......还有15个

Answer 1

您收到错误是因为您尚未初始化标签ArrayList中的元素。如果您从索引0开始添加它将起作用，但由于索引1尚未为您初始化，因此会导致indexoutofbounds异常。

为什么variable.add（index，element）会创建一个空错误？

1 个答案: