java - 应为字符串，但为BEGIN_OBJECT我必须返回字符串

类

 class PrintRequest {
        private String data;
        private String userImageBase64;
        private String organizationImageBase64;
        private String fileBase64;
     //getters and setters
    }

用
PrintRequest printRequest = gson.fromJson(request.getBody(), PrintRequest.class);

json

{
   "data":{
      "nazwaDostawcy":"nazwa dostawcy (opis)",
      "nazwa":"Gniazdo przemysłowe, kątowe, 2p+E, 16A, 100...130 V AC, IP 44 ",
      "kod":"val",
      "kodEan":"val",
      "kodWewnrtrzny":"val",
      "cennaNetto":"val"
   },
   "fileBase64":""
}

就像在主题中一样，我理解为什么会收到此错误，但是我需要将data作为字符串返回。我如何实现我的目标？

感谢帮助！

最佳答案

这是不创建自定义gson序列化的最简单方法。只需重写toString（）方法

public class PrintRequest {
     private Value data;
     private String userImageBase64;
     private String organizationImageBase64;
     private String fileBase64;
     //getters and setters
}

public class Value {
    String nazwaDostawcy;

    @Override
    public String toString() {
        return "Value{" +
            "nazwaDostawcy='" + nazwaDostawcy + '\'' +
            ", nazwa='" + nazwa + '\'' +
            ", kod='" + kod + '\'' +
            ", kodEan='" + kodEan + '\'' +
            ", kodWewnrtrzny='" + kodWewnrtrzny + '\'' +
            ", cennaNetto='" + cennaNetto + '\'' +
            ", kategoria='" + kategoria + '\'' +
            ", opis='" + opis + '\'' +
            ", logo1='" + logo1 + '\'' +
            ", logo2='" + logo2 + '\'' +
            '}';
}

String nazwa;
String kod;
String kodEan;
String kodWewnrtrzny;
String cennaNetto;
String kategoria;
String opis;
String logo1;
String logo2;
//getters and setters
}

用法：

PrintRequest printRequest = gson.fromJson（json，PrintRequest.class）;
System.out.println（printRequest.getData（）。toString（））;

UPD：

定制JsonDeserializer的解决方案

public class CustomJsonDeserializer implements JsonDeserializer<PrintRequest> {

    @Override
    public PrintRequest deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
        PrintRequest printRequest = new PrintRequest();
        JsonObject jsonObject = jsonElement.getAsJsonObject();
        String dataStr="";
        JsonObject jsonObjectData = jsonObject.getAsJsonObject("data");
        for (Data data : Data.values()) {
            dataStr+=(data.name() + ":" + jsonObjectData.get(data.name()).getAsString()+",\n");
        }
        printRequest.setData(dataStr);
        return printRequest;
    }
}


public enum Data {
    nazwaDostawcy,
    nazwa
}

public class PrintRequest {
    private String data;
    private String userImageBase64;
    private String organizationImageBase64;
    private String fileBase64;
    //getters and setters

用法：

GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES);
        gsonBuilder.registerTypeAdapter(PrintRequest.class, new CustomJsonDeserializer());
        Gson gson = gsonBuilder.create();
        PrintRequest printRequest = gson.fromJson(json, PrintRequest.class);
        System.out.println(printRequest.getData());

关于java - 应为字符串，但为BEGIN_OBJECT我必须返回字符串，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/58953073/