Question

我今天第一次使用GSON。现在我正在尝试使用值反序列化序列化类。 Deserialise完美地工作，但在加载时它只输出所有字段为null。我真的想知道我做错了什么，或者为什么它不起作用。

要填写的课程：

public class PlayerData {

    private static Map<UUID, PlayerData> playerDataMap = new HashMap<UUID, PlayerData>();
    public UUID uuid;
    public Integer kills;
    public Integer level;
    public Integer xp;
    public SkillType skillType;

    public PlayerData() {
        playerDataMap.put(getUUID(), this);
        String logString = "[DEBUG] " + uuid + " " + skillType + " " + level;
        ZombieSurvival.getInstance().getLogger().info(logString);
    }
}

保存代码：

private synchronized void savePlayerData(){
    try {
        Map<UUID, PlayerData> map = PlayerData.getPlayerDataMap();
        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        String seperator = File.separator;
        String path = getDataFolder().getAbsolutePath() + seperator + "PlayerData" + seperator;
        File folder = new File(path);
        folder.mkdirs();
        for(UUID uuid : map.keySet()){
            PlayerData pd = map.get(uuid);
            String json = gson.toJson(pd);
            File myFile = new File(folder,uuid.toString() + ".json");
            myFile.createNewFile();
            FileOutputStream fOut = new FileOutputStream(myFile);
            OutputStreamWriter myOutWriter =new OutputStreamWriter(fOut);
            myOutWriter.append(json);
            myOutWriter.close();
            fOut.close();
        }
    } catch (Exception e){
        e.printStackTrace();
    }
}

信息：JSON内容是由此方法创建的！

加载代码：

private void loadPlayerData() {
    try {
        //Setup GSON Loading
        String seperator = File.separator;
        File invasionMobFolder = new File(getDataFolder() + seperator + "PlayerData" + seperator);
        invasionMobFolder.mkdirs();
        File[] listOfFiles = invasionMobFolder.listFiles();
        for (File file : listOfFiles) {
            if (file.getName().endsWith(".json")) {
                FileInputStream fIn = new FileInputStream(file);
                BufferedReader myReader = new BufferedReader(new InputStreamReader(fIn));
                String aDataRow = "";
                String aBuffer = ""; //Holds the text
                while ((aDataRow = myReader.readLine()) != null) {
                    aBuffer += aDataRow;
                }
                myReader.close();
                Gson gson = new Gson();
                gson.fromJson(aBuffer, PlayerData.class);
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

JSON内容：

{
    "uuid": "ba79c71f-aa2c-4f8b-a7e5-d6bfea7a4dcc",
    "kills": 0,
    "level": 0,
    "xp": 0,
    "skillType": "KNIGHT"
}

Answer 1

正如Steve Bishop所说或试图说的那样，import Foundation func flatten< T, U >( _ elem: T ) -> [ U ] { if let item = elem as? U { return [ item ] } else { return [] } } func flatten< T, U >( _ ary: [ T ] ) -> [ U ] { if ary.count == 0 { return [] } return flatten( ary.first ) + flatten( Array( ary.dropFirst() ) ) } let x: [ Int ] = flatten( [ 1, 2, [ 3, 4 ], [ [ 5, 6 ], nil, 7 ], 8, 9 ] ) print( x ) // Prints [1, 2, 8, 9 ] instead of [1, 2, 3, 4, 5, 6, 7, 8, 9]中gson.fromJson方法调用的返回值未被使用。如果要将PlayerData对象保存为静态变量，则无法在每个PlayerData类的构造函数中执行此操作，因为GSON很可能首先调用构造函数，然后使用您的匹配字段填充变量json字符串通过反射导致您的空填充字段。

您需要做的是从loadPlayerData获取反序列化的JSON并将其放入您的静态gson.fromJson字段中，该字段显然至少需要一个公共设置器。

Answer 2

您的字段是私有的，GSON默认只映射公共字段。

Answer 3

您没有保存结果。

private List<PlayerData> loadPlayerData(){
    List<PlayerData> players = new ArrayList<>();
    try {
        //Setup GSON Loading
        String seperator = File.separator;
        File invasionMobFolder = new File(getDataFolder() + seperator + "PlayerData" + seperator);
        invasionMobFolder.mkdirs();
        File[] listOfFiles = invasionMobFolder.listFiles();
        for(File file : listOfFiles){
            if(file.getName().endsWith(".json")){
                FileInputStream fIn = new FileInputStream(file);
                BufferedReader myReader = new BufferedReader(new InputStreamReader(fIn));
                String aDataRow = "";
                String aBuffer = ""; //Holds the text
                while ((aDataRow = myReader.readLine()) != null)
                {
                    aBuffer += aDataRow ;
                }
                myReader.close();
                Gson gson = new Gson();
                players.add(gson.fromJson(aBuffer, PlayerData.class));
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return players;
}

GSON将所有字段设置为null

3 个答案: