杰克逊的问题问题将所有变量设置为空

Question

我正在尝试，但在杰克逊（Jackson）2.9.2中未能进行挑选，我正在尝试制作游戏，用于一个我正在从事保存功能的Uni项目，我可以保存我的玩家类并序列化，但是当我尝试对其进行挑选并从中制作新播放器时，它将所有变量设置为null，这是我的方法：

public void LoadSaveString() throws IOException{
    ObjectMapper mapper = new ObjectMapper();
    SimpleModule module = new SimpleModule();
    //module.addDeserializer(SaveFile.class, new SaveDeserializer());
    mapper.registerModule(module);
    String filePath = "files/SaveFile.json";
    BufferedReader reader = new BufferedReader(new FileReader(filePath)); 
    testfile = reader.readLine();
    System.out.println("Stringen testfilen bliver printet: " + testfile);
    Player player1 = (Player) mapper.readValue(testfile, Player.class);
    System.out.println("Test 2: " + player1.toString());
}

我得到的输出是：

串起testfilen bliver printet：{" player"：{" hp"：100，" air"：97，contectory'：[]，" hascalledHelp"：false，false，" wongame"：wongame"：false"，" playername"："MADS"，" AwesomePoints"：0，" totalTimePlayed"：3，" terminateThreads"：false，" propthreadoxygen"：false，" potthreadhp"：false，false，" name"：" mads"}}}

测试2：player {hp = 0，air = 0，inting = null，hasCalledHelp = false，wongame = false，aveathypoints = 0，totaltimeplayed = 0，terminateThreads = false，propthreadoxygen = falseP>

我已经将玩家类设置为忽略未知属性，所以我只能获取并设置对Playerclass很重要的事物

@JsonIgnoreProperties(ignoreUnknown = true)

和我的玩家类中的属性：

public class Player {
private int hp;
private int air;
private ArrayList<Item> inventory;
private boolean hasCalledHelp = false;
private boolean wonGame = false;
public String playerName = "Mads"; // Non-negotiable
public int awesomePoints = 0;
public int totalTimePlayed = 0;

编辑：

文件savefile.json中的内容：

{
    "player": {
        "hp": 100,
        "air": 97,
        "inventory": [],
        "hasCalledHelp": false,
        "wonGame": false,
        "playerName": "Mads",
        "awesomePoints": 0,
        "totalTimePlayed": 3,
        "terminateThreads": false,
        "stopThreadOxygen": false,
        "stopThreadHP": false,
        "name": "Mads"
    }
}

Answer 1

首先，我建议您不仅读一行，而且还读了整个文件。只是为了确保支持其他格式的JSON文件。另外，正如Tobias已经说过的那样，JSON文件不是"播放器"，它仅包含一个播放器。或者，与Tobias的方法相比，您也可以在JSON文件中选择播放器部分。

public void LoadSaveString() throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    SimpleModule module = new SimpleModule();
    mapper.registerModule(module);
    String filePath = "files/SaveFile.json";
    //Read the whole file and not just one line
    byte[] encoded = Files.readAllBytes(Paths.get(filePath));
    String testfile = new String(encoded, "utf-8");
    JSONObject json = new JSONObject(testfile);
    //Pick only the player part
    String playerPart = json.getJSONObject("player").toString();
    System.out.println("Stringen testfilen bliver printet: " + testfile);
    Player player1 = (Player) mapper.readValue(playerPart, Player.class);
    System.out.println("Test 2: " + player1.toString());
}

还需要每个属性的玩家类别：

@JsonIgnoreProperties(ignoreUnknown = true)
public class Player {
    private int hp;
    private int air;
    private boolean hasCalledHelp = false;
    private boolean wonGame = false;
    public String playerName = "Mads"; // Non-negotiable
    public int awesomePoints = 0;
    public int totalTimePlayed = 0;
    public int getHp() {
        return hp;
    }
    public void setHp(int hp) {
        this.hp = hp;
    }
    public int getAir() {
        return air;
    }
    public void setAir(int air) {
        this.air = air;
    }
    public boolean isHasCalledHelp() {
        return hasCalledHelp;
    }
    public void setHasCalledHelp(boolean hasCalledHelp) {
        this.hasCalledHelp = hasCalledHelp;
    }
    public boolean isWonGame() {
        return wonGame;
    }
    public void setWonGame(boolean wonGame) {
        this.wonGame = wonGame;
    }
    public String getPlayerName() {
        return playerName;
    }
    public void setPlayerName(String playerName) {
        this.playerName = playerName;
    }
    public int getAwesomePoints() {
        return awesomePoints;
    }
    public void setAwesomePoints(int awesomePoints) {
        this.awesomePoints = awesomePoints;
    }
    public int getTotalTimePlayed() {
        return totalTimePlayed;
    }
    public void setTotalTimePlayed(int totalTimePlayed) {
        this.totalTimePlayed = totalTimePlayed;
    }
}

Answer 2

文件的JSON是具有属性player的Object。这不是Player

{
    "player": { "hp":100, ... }
}        

类似：

public class PlayerWrapper {
    public player Player;
}

json应该是

{
    "hp":100,
    "air":97,
    "inventory":[],
    "hasCalledHelp":false,
    "wonGame":false,
    "playerName":"Mads",
    "awesomePoints":0,
    "totalTimePlayed":3,
    "terminateThreads":false,
    "stopThreadOxygen":false,
    "stopThreadHP":false,
    "name":"Mads"
}

，或者如果无法更改文件，则使用PlayerWrapper：

mapper.readValue(testfile, PlayerWrapper.class)