收集具体论点

Question

我正在 java 中开发一个游戏插件，但无法解决这个问题。我想在 args[1] 之后收集所有内容。这里有一些代码，所以你可以更好地理解。

    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
    if(sender instanceof Player) {
        Player player = (Player) sender;
        if(player.hasPermission("essentials.allow.kick")) {
            if(args.length == 0) {
                player.sendMessage(ChatColor.RED + "Please specify player name.");
            }
            if(args.length == 1) {
                Player target = Bukkit.getPlayer(args[0]);
                if(!target.isValid()) {
                    player.sendMessage(ChatColor.RED + "That player is not on server!");
                }else {
                    target.kickPlayer(ChatColor.RED + "The kick reason has been told!");
                }
            }
            if(args.length > 1) {
                Player target = Bukkit.getPlayer(args[0]);
                if(!target.isValid()) {
                    player.sendMessage(ChatColor.RED + "That player is not on server!");
                }
                else {
                    String message = Stream.of(args).skip(2).collect(Collectors.toList()).toString();
                    target.kickPlayer(ChatColor.RED + message);
                }
            }
        }
    }
    return true;
}

它只输出[]。

Answer 1

为了收集n-th元素之后的数组的所有元素，可以使用ArrayListclass的subList(int fromIndex, int toIndex)函数。文档说：

Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive.

因此您需要将数组转换为 List，然后在其上调用函数 subList。

List<String> list = Arrays.asList(args).sublist(1, args.length);
// Replace number 1 with the start index where you want to trim. (Inclusive)

现在，如果您想将该列表转换为字符串，您可以使用以下函数：

public String buildMessage(List<String> list, String separator) {
    StringBuilder sb = new StringBuilder();
    for (String s: list) {
        sb.append(s).append(separator);
    }
    return sb.toString();
}

然后调用它：

String message = buildMessage(list, " "); // It will separate the arguments with spaces.

完整演示

String[] args = new String[]{"Hi!", "I", "am", "a", "demo"};
List<String> list = Arrays.asList(args).sublist(1, args.length);
String message = buildMessage(list, " ");
System.out.println("Message: " + message);

产生的输出：

Message: I am a demo

让我知道这是否适合您！

编辑

如 @Holger 的评论所述，您可以将完整的演示简化为：

完整演示

String[] args = new String[]{"Hi!", "I", "am", "a", "demo"};
List<String> list = Arrays.asList(args).sublist(1, args.length);
String message = String.join(" ", list);
System.out.println("Message: " + message);

那么你就不需要buildMessage方法了。

收集具体论点

Collecting specific arguments

java

arrays

bukkit

collectors