Bukkit NullPointer插件参考

Question

我正在制作一个bukkit插件，它使用一个配置来存储数据，但是当我使用plugin.getConfig()时，我得到了一个NullPointer。我想是因为对插件的引用，但我如何解决这个问题呢？

错误出现在我使用插件的Storage类中。实例

主营：http://pastebin.com/d3bFXbiR

import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.block.Block;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.entity.LivingEntity;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.block.Action;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin {

   public void onEnable() {
      final FileConfiguration config = this.getConfig();

      config.options().copyDefaults(true);
      saveConfig();

   }

   @Override
   public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {

      if (cmd.getName().equalsIgnoreCase("BlockCmd")) {

         if (sender.isOp()) {
            if (args.length < 1) {
               sender.sendMessage(ChatColor.RED + "/BlockCmd [command] | Kijk naar het blok dat je wilt cmd'en");
            } else {
               Block block = ((LivingEntity) sender).getTargetBlock(null, 100);
               Location bl = block.getLocation();

               StringBuilder sb = new StringBuilder();
               for (int i = 1; i < args.length; i++) {
                  sb.append(args[i]).append(" ");
               }

               String allArgs = sb.toString().trim();

               Storage.addClickCmd(bl, allArgs);
               sender.sendMessage(ChatColor.GRAY + "[BlockCommand] " + ChatColor.BLUE + "Successfully added a command to the block");
               sender.sendMessage(ChatColor.GRAY + "[BlockCommand] " + ChatColor.BLUE + "Command: " + ChatColor.GREEN + allArgs);

            }

         } else {
            sender.sendMessage(ChatColor.RED + "Dit is alleen voor operators");
         }

      }
      return true;
   }

   @EventHandler
   public void onRightClick(PlayerInteractEvent event) {
      Player p = event.getPlayer();
      if ((event.getAction() == Action.RIGHT_CLICK_BLOCK) || (event.getAction() == Action.LEFT_CLICK_BLOCK)) {
         Location loc = event.getClickedBlock().getLocation();
         int x = loc.getBlockX();
         int y = loc.getBlockY();
         int z = loc.getBlockZ();
         String w = p.getWorld().getName();

         String cCc = "Click.Cmd." + w + "." + x + "." + y + "." + z;

         if (Storage.getClickCmd(w, x, y, z) != null) {
            String cCc2 = Storage.getString(cCc);
            p.performCommand(cCc2);
         }

      }
   }
}

存储：http://pastebin.com/wvQS3n57

import org.bukkit.Location;
import org.bukkit.event.Listener;

public class Storage implements Listener {

   static Main plugin;

   public Storage(Main instance) {
      plugin = instance;
   }

   public static void addClickCmd(Location loc, String text) {
      int x = loc.getBlockX();
      int y = loc.getBlockY();
      int z = loc.getBlockZ();
      String w = loc.getWorld().getName();

      if (plugin != null && plugin.getConfig() != null) {
         System.out.println("Check");
      }
        //if(plugin.getConfig() !=null){}
      //plugin.getConfig().set("Click.Cmd." + w + "." + x + "." + y + "." + z, text);
   }

   public static String getClickCmd(String w, int x, int y, int z) {
      return plugin.getConfig().getString("Click.Cmd." + w + "." + x + "." + y + "." + z);
   }

   public static String getString(String path) {
      return plugin.getConfig().getString(path);
   }
}

Answer 1

您使用static Main plugin;，但它从未初始化，因为您从未实例化Storage对象，而只使用它的静态函数。

在您的插件类中，创建一个Storage对象，并在onEnable方法中初始化它，将插件传递给它的构造函数。例如：

public class Main extends JavaPlugin {

   Storage myStorage = null;

   public void onEnable() {
       final FileConfiguration config = this.getConfig();

       config.options().copyDefaults(true);
       saveConfig();
       myStorage = new Storage(this);
   }

稍后在您的插件类中使用这个对象，最好是在Storage (以及plugin成员)中使静态方法非静态，因为您总是需要创建一个实例来使用构造函数中的plugin集。

我认为这的文章给出了一个很好的、基本的关于类成员的概述。