文件夹。getPlayersConfig（）。contains（）引发NullPointerException

Question

所以我目前正在开发一个Bukkit（技术上是插口插件），我希望当一个玩家第一次加入时，它能在一个文件（players.yml）中生成一个字符串。

我目前有：

public void onPlayerJoin(PlayerJoinEvent e){
    String player = e.getPlayer().getName().toString();

    if(!files.getPlayersConfig().contains(player)) {
        files.getPlayersConfig().set(player + ".enabled", true);
        files.getPlayersConfig().set(player + ".money", 100);
        files.savePlayersConfig();
        files.reloadPlayersConfig();
    }
}

我基本上要做的是在每个玩家第一次加入时在文件中创建一个字符串“player”。

例如，如果一个球员的名字鲍勃第一次加入，该文件将生成

bob:
    enabled: true
    money: 100

但是，我不希望每次玩家加入时都重置它，因此我尝试让它检查文件是否包含“bob”，如果返回null，它将创建它。我的问题是，它显示为一个错误，而不是仅仅创建它，所以它不是空的。

（抱歉措辞不好，但有点难以解释。）

谢谢

日志：

PlayerJoinEvent to McEconPlus v1.0
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:305) ~[spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.PlayerList.onPlayerJoin(PlayerList.java:262) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.PlayerList.a(PlayerList.java:147) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.LoginListener.b(LoginListener.java:109) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.LoginListener.c(LoginListener.java:41) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.NetworkManager.a(NetworkManager.java:159) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.ServerConnection.c(ServerConnection.java:82) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:785) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:623) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:526) [spigot.jar:git-Spigot-8dc4297-fbda3a7]
    at java.lang.Thread.run(Unknown Source) [?:1.7.0_67]
**Caused by: java.lang.NullPointerException**
    at me.mrson.McEconPlus.Events.MCEP_CreatePlayers.onPlayerJoin(MCEP_CreatePlayers.java:21) ~[?:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_67]
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301) ~[spigot.jar:git-Spigot-8dc4297-fbda3a7]
    ... 14 more

根据要求的主要类：

公共类MCEP_Base扩展了JavaPlugin{私有静态插件Plugin；

public File configFile = new File(this.getDataFolder(), "config.yml");
public FileConfiguration config = YamlConfiguration.loadConfiguration(configFile);

public File playersFile = new File(this.getDataFolder(), "players.yml");
public FileConfiguration players = YamlConfiguration.loadConfiguration(playersFile);


public void onEnable(){
    plugin = this;

    //config

    config.options().copyDefaults(true);
    config.addDefault("Enabled", "true");
    this.saveCustomConfig();

    players.options().copyDefaults(true);
    players.addDefault("Enabled", true);
    this.savePlayersConfig();

    //Logger
    this.getLogger().log(Level.FINEST, "[McEcon+] Enabling.");

    //Commands
    getCommand("econ").setExecutor(new MCEP_Econ());
    getCommand("pay").setExecutor(new MCEP_Pay());
    getCommand("sell").setExecutor(new MCEP_Sell());

    //Events
    registerEvents(this, new MCEP_CreatePlayers());


}

public void onDisable(){
    plugin = null;
}

public static void registerEvent(Plugin plugin, Listener... listeners){
    for(Listener listener : listeners){
        Bukkit.getServer().getPluginManager().registerEvents(listener, plugin);
    }
}

public static Plugin getPlugin() {
    return plugin;
}

public void saveCustomConfig(){
    try{
        config.save(configFile);
    }catch(IOException ex){
        ex.printStackTrace();
    }
}

public void savePlayersConfig(){
    try{
        players.save(playersFile);
    }catch(IOException ex){
        ex.printStackTrace();
    }
}

public FileConfiguration getCustomConfig(){
    if(config == null){
        saveCustomConfig();
    }
    return config;
}

public FileConfiguration getPlayersConfig() {
    if (players == null) {
        savePlayersConfig();
    }
    return players;
}

public void reloadCustomConfig(){
    if(configFile == null){
        configFile = new File(getDataFolder(), "config.yml");
    }
    config = YamlConfiguration.loadConfiguration(configFile);
    config.set("Enabled", true);
}

public void reloadPlayersConfig(){
    if(playersFile == null){
        playersFile = new File(getDataFolder(), "players.yml");
    }
    players = YamlConfiguration.loadConfiguration(playersFile);
    players.set("Enabled", true);
}

public static void registerEvents(org.bukkit.plugin.Plugin plugin, Listener... listeners) {
    for (Listener listener : listeners) {
        Bukkit.getServer().getPluginManager().registerEvents(listener, plugin);
    }
}

}

与我的Listener类一起：

公共类MCEP\u CreatePlayers实现监听器{MCEP\u基文件；

@EventHandler()
public void onPlayerJoin(PlayerJoinEvent e){
    String player = e.getPlayer().getName().toString();
    if(files == null){
        MCEP_Base.getPlugin().getLogger().warning("Test");
    }else if(files.getPlayersConfig() == null){
        MCEP_Base.getPlugin().getLogger().warning("Test1");
    }
    else if(!files.players.contains(player)) {
        files.getPlayersConfig().set(player + ".enabled", true);
        files.getPlayersConfig().set(player + ".money", 100);
        files.savePlayersConfig();
        files.reloadPlayersConfig();
    }
}

}

Answer 1

您可以添加另一个检查以查看getPlayersConfig（）是否返回null：

if(files.getPlayersConfig() == null) {
// handle this case
}
else if(!files.getPlayersConfig().contains(player)) {
// continue with rest of your code
}