Java 将JSON作为对象列表读取-Jackson

我有一个Json字符串，如下所示

{
  "EngineData": [
    {
      "make": "Toyota",
      "transmission": "Manual",
      "fuel": "Petrol"
    },
    {
      "make": "GMC",
      "transmission": "Auto",
      "fuel": "Petrol"
    },
    {
      "make": "Honda",
      "transmission": "Manual",
      "fuel": "Petrol"
    }
  ]
}

@JsonIgnoreProperties(ignoreUnknown = true)
public class EngineData implements Serializable {
    @JsonProperty("make")
    private String make;
    @JsonProperty("transmission")
    private String transmission;
    @JsonProperty("fuel")
    private String fuel;

    //getters and setters
    
}

我有如下定义的POJO

{
  "EngineData": [
    {
      "make": "Toyota",
      "transmission": "Manual",
      "fuel": "Petrol"
    },
    {
      "make": "GMC",
      "transmission": "Auto",
      "fuel": "Petrol"
    },
    {
      "make": "Honda",
      "transmission": "Manual",
      "fuel": "Petrol"
    }
  ]
}

@JsonIgnoreProperties(ignoreUnknown = true)
public class EngineData implements Serializable {
    @JsonProperty("make")
    private String make;
    @JsonProperty("transmission")
    private String transmission;
    @JsonProperty("fuel")
    private String fuel;

    //getters and setters
    
}

我想把它读到

List

我写了以下内容，但它没有将字符串读入EngineData列表

List<EngineData> engineDataList =null;
ObjectMapper mapper = new ObjectMapper();
engineDataList = mapper.readValue(myJsonString, new TypeReference<List<EngineData>>() {
            });

List engineDataList=null；
ObjectMapper mapper=新的ObjectMapper（）；
engineDataList=mapper.readValue（myJsonString，新类型引用（）{
});

---

不确定这有什么问题，您的JSON对应一个对象，例如：

class CustomObject {
   List<EngineData> EngineData;
   //...
}

---

如果您被迫使用这个JSON，我认为您需要编写一个自定义反序列化程序。cf.

您的JSON对应一个对象，例如：

class CustomObject {
   List<EngineData> EngineData;
   //...
}

---

如果您被迫使用这个JSON，我认为您需要编写一个自定义反序列化程序。cf.

对象无法映射到列表

有关映射给定json的信息，请参阅：

public class EngineDataList {
   @JsonProperty("EngineData")
   List<EngineData> EngineData;
}

EngineDataList engineDataList =null;
ObjectMapper mapper = new ObjectMapper();
engineDataList = mapper.readValue(myJsonString, new TypeReference<EngineDataList>() {});

公共类EngineDataList{
@JsonProperty（“EngineData”）
列出引擎数据；
}
EngineDataList EngineDataList=null；
ObjectMapper mapper=新的ObjectMapper（）；
engineDataList=mapper.readValue（myJsonString，newTypeReference（）{}）；

对象无法映射到列表

有关映射给定json的信息，请参阅：

public class EngineDataList {
   @JsonProperty("EngineData")
   List<EngineData> EngineData;
}

EngineDataList engineDataList =null;
ObjectMapper mapper = new ObjectMapper();
engineDataList = mapper.readValue(myJsonString, new TypeReference<EngineDataList>() {});

公共类EngineDataList{
@JsonProperty（“EngineData”）
列出引擎数据；
}
EngineDataList EngineDataList=null；
ObjectMapper mapper=新的ObjectMapper（）；
engineDataList=mapper.readValue（myJsonString，newTypeReference（）{}）；