Java IllegalArgumentException: Bound 必须为正
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IllegalArgumentException: Bound must be positive
提问by Guus Huizen
I get an error saying that my bound must be positive. Here is the line I get it on:
我收到一个错误，说我的界限必须是正数。这是我得到它的线路：
inv.setItem(i, items.get(r.nextInt(items.size())));
As far as I know, it comes from the part where I request a random integer from the list of items. This is how I defined the list:
据我所知，它来自我从项目列表中请求一个随机整数的部分。这就是我定义列表的方式：
List<ItemStack> items = getAllItems(level);
Where the getAllItems()method looks like:
该getAllItems()方法如下所示：
public List<ItemStack> getAllItems(int level) {
List<ItemStack> items = new ArrayList<ItemStack>();
for (String item : settings.getChests().getStringList("chestitems." + level)) {
ItemStack toAdd = parseItem(item);
items.add(toAdd);
}
return items;
}
I get this stacktrace:
我得到这个堆栈跟踪：
[19:03:53 ERROR]: Error occurred while enabling KitPvP v0.5 (Is it up to date?)
java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_51]
at me.iamguus.gamegetsiepunt.kitpvp.chests.ChestsUtil.randomlyFillInv(ChestsUtil.java:101) ~[?:?]
at me.iamguus.gamegetsiepunt.kitpvp.Main.onEnable(Main.java:40) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:335) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.reload(CraftServer.java:746) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.Bukkit.reload(Bukkit.java:534) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:25) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:646) [spigot.jar:git-Spigot-5818108-a486600]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:632) [spigot.jar:git-Spigot-5818108-a486600]
at net.minecraft.server.v1_8_R3.DedicatedServer.aO(DedicatedServer.java:405) [spigot.jar:git-Spigot-5818108-a486600]
at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:369) [spigot.jar:git-Spigot-5818108-a486600]
at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) [spigot.jar:git-Spigot-5818108-a486600]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot.jar:git-Spigot-5818108-a486600]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_51]
回答by Swapnil
As far as your stacktrace says,
至于你的堆栈跟踪说，
java.lang.IllegalArgumentException: bound must be positive at java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_51]
java.lang.IllegalArgumentException：在 java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_51] 时边界必须为正
The argument to nextInt needs to be a positive integer. You will need to find out where you're passing a non-positive input to that method.
nextInt 的参数需要是一个正整数。您需要找出将非正输入传递给该方法的位置。
回答by Todd
The issue is that you are calling Random.nextInt()with a zero and it doesn't like that. That is happening because the Listfrom getAllItems()is empty. I would prevent this situation by checking that the list has items before performing your logic:
问题是你Random.nextInt()用零打电话，它不喜欢那样。这是因为ListfromgetAllItems()是空的。我会通过在执行逻辑之前检查列表中是否包含项目来防止这种情况：
List<ItemStack> items = getAllItems(level);
if(!items.isEmpty()) {
inv.setItem(i, items.get(r.nextInt(items.size())));
}
