Java 使用Gson解析单个json条目到多个对象

我有一个json响应，如下所示：

{
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2"
}

  {
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2",
    "events":[
        {
            "id":"01",
            "value":"22.5"
        },
        {
            "id":"02",
            "value":"31.0"
        }
    ]
}

public class TestDeserializer implements JsonDeserializer<Test> {
    @Override
    public Test deserialize(JsonElement json, Type type,
            JsonDeserializationContext context) throws JsonParseException {

        JsonObject obj = json.getAsJsonObject();

        Test test = new Test();
        test.setId(obj.get("id").getAsInt());
        test.setName(obj.get("name").getAsString());        

        Parameters params = new Parameters();
        params.setDistance(obj.get("param_distance").getAsDouble());
        params.setSampling(obj.get("param_sampling").getAsInt());
        test.setParameters(params);

        Gson eventGson = new Gson();
        Type eventsType = new TypeToken<List<Event>>(){}.getType();
        List<Event> eventList = eventGson.fromJson(obj.get("events"), eventsType);
        test.setEvents(eventList);
        return test;
    }
}

private class TestDeserializer implements JsonDeserializer<Test> {
  public Test deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException {

    JsonObject obj = json.getAsJsonObject();

    int id = obj.get("id").getAsInt();
    String name = obj.get("name").getAsString();

    double distance = obj.get("param_distance").getAsDouble();
    int sampling = obj.get("param_sampling").getAsInt();

    //assuming you have suitable constructors...
    Test test = new Test(id, name, new Parameters(distance, sampling));

    return test;
  }
}

我有两个类：Teste和Parameters

public class Test {
    private int id;
    private String name;
    private Parameters params;
}

public class Parameters {
    private double distance;
    private int sampling;
}

我的问题是：有没有一种方法可以让Gson理解一些json属性应该转到Parameters类，或者唯一的方法是“手动”解析它

编辑 好吧，让我在@MikO的回答中的评论更具可读性：

我将向json输出中添加一个对象列表，因此json响应应该如下所示：

{
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2"
}

  {
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2",
    "events":[
        {
            "id":"01",
            "value":"22.5"
        },
        {
            "id":"02",
            "value":"31.0"
        }
    ]
}

public class TestDeserializer implements JsonDeserializer<Test> {
    @Override
    public Test deserialize(JsonElement json, Type type,
            JsonDeserializationContext context) throws JsonParseException {

        JsonObject obj = json.getAsJsonObject();

        Test test = new Test();
        test.setId(obj.get("id").getAsInt());
        test.setName(obj.get("name").getAsString());        

        Parameters params = new Parameters();
        params.setDistance(obj.get("param_distance").getAsDouble());
        params.setSampling(obj.get("param_sampling").getAsInt());
        test.setParameters(params);

        Gson eventGson = new Gson();
        Type eventsType = new TypeToken<List<Event>>(){}.getType();
        List<Event> eventList = eventGson.fromJson(obj.get("events"), eventsType);
        test.setEvents(eventList);
        return test;
    }
}

private class TestDeserializer implements JsonDeserializer<Test> {
  public Test deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException {

    JsonObject obj = json.getAsJsonObject();

    int id = obj.get("id").getAsInt();
    String name = obj.get("name").getAsString();

    double distance = obj.get("param_distance").getAsDouble();
    int sampling = obj.get("param_sampling").getAsInt();

    //assuming you have suitable constructors...
    Test test = new Test(id, name, new Parameters(distance, sampling));

    return test;
  }
}

反序列化器类如下所示：

{
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2"
}

  {
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2",
    "events":[
        {
            "id":"01",
            "value":"22.5"
        },
        {
            "id":"02",
            "value":"31.0"
        }
    ]
}

public class TestDeserializer implements JsonDeserializer<Test> {
    @Override
    public Test deserialize(JsonElement json, Type type,
            JsonDeserializationContext context) throws JsonParseException {

        JsonObject obj = json.getAsJsonObject();

        Test test = new Test();
        test.setId(obj.get("id").getAsInt());
        test.setName(obj.get("name").getAsString());        

        Parameters params = new Parameters();
        params.setDistance(obj.get("param_distance").getAsDouble());
        params.setSampling(obj.get("param_sampling").getAsInt());
        test.setParameters(params);

        Gson eventGson = new Gson();
        Type eventsType = new TypeToken<List<Event>>(){}.getType();
        List<Event> eventList = eventGson.fromJson(obj.get("events"), eventsType);
        test.setEvents(eventList);
        return test;
    }
}

private class TestDeserializer implements JsonDeserializer<Test> {
  public Test deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException {

    JsonObject obj = json.getAsJsonObject();

    int id = obj.get("id").getAsInt();
    String name = obj.get("name").getAsString();

    double distance = obj.get("param_distance").getAsDouble();
    int sampling = obj.get("param_sampling").getAsInt();

    //assuming you have suitable constructors...
    Test test = new Test(id, name, new Parameters(distance, sampling));

    return test;
  }
}

---

按我想要的方式给我测试对象

让Gson理解它的方法是通过为

测试

类创建

类型适配器

来编写自定义反序列化程序。您可以在中找到信息。这并不完全是一个手动解析，但也没有什么不同，因为您必须告诉Gson如何处理每个JSON值

应该是这样的：

{
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2"
}

  {
    "id":"001",
    "name":"Name",
    "param_distance":"10",
    "param_sampling":"2",
    "events":[
        {
            "id":"01",
            "value":"22.5"
        },
        {
            "id":"02",
            "value":"31.0"
        }
    ]
}

public class TestDeserializer implements JsonDeserializer<Test> {
    @Override
    public Test deserialize(JsonElement json, Type type,
            JsonDeserializationContext context) throws JsonParseException {

        JsonObject obj = json.getAsJsonObject();

        Test test = new Test();
        test.setId(obj.get("id").getAsInt());
        test.setName(obj.get("name").getAsString());        

        Parameters params = new Parameters();
        params.setDistance(obj.get("param_distance").getAsDouble());
        params.setSampling(obj.get("param_sampling").getAsInt());
        test.setParameters(params);

        Gson eventGson = new Gson();
        Type eventsType = new TypeToken<List<Event>>(){}.getType();
        List<Event> eventList = eventGson.fromJson(obj.get("events"), eventsType);
        test.setEvents(eventList);
        return test;
    }
}

private class TestDeserializer implements JsonDeserializer<Test> {
  public Test deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException {

    JsonObject obj = json.getAsJsonObject();

    int id = obj.get("id").getAsInt();
    String name = obj.get("name").getAsString();

    double distance = obj.get("param_distance").getAsDouble();
    int sampling = obj.get("param_sampling").getAsInt();

    //assuming you have suitable constructors...
    Test test = new Test(id, name, new Parameters(distance, sampling));

    return test;
  }
}

最后，您只需像往常一样解析JSON，使用：

gson.fromJson(yourJsonString, Test.class);

---

Gson将自动使用您的自定义反序列化程序将JSON解析到您的

Test

类中。

Yep。我曾经在一些代码中使用过很多“示例”。这里有一个类，但该目录中的大多数内容都有一个自定义适配器：Ok。成功了。但让我们把问题复杂化一点。我在这个测试课上也有一个列表。列表如何在此方法中包含此列表解析。根据我所读的，我必须使用JsonArray类，对吗？好的。我的活动列表也在运行。您可以获取元素并使用regular Gson对象对其进行解析

Gson eventGson=new Gson（）；类型eventsType=newTypeToken（）{}.getType（）；List eventList=eventGson.fromJson（obj.get（“事件”），eventsType）；test.setEvents（事件列表）Json输入应该是这样的：
{“id”：“001”，“name”：“name”，“param_distance”：“10”，“param_sampling”：“2”，“events”：[{“id”：“01”}，{“id”：“02”}]}
我已经用这些信息更新了我的问题。谢谢你的帮助……=）