为什么我的 JSON 映射器无法识别我的对象？

Question

public class ResponseList implements Serializable {

    private String sku;

    private String query;

    private List<QAResponse> responses;

    // getter and setter

}

第二类：

public class QAResponse implements Serializable {

    private AnswerLevel answerLevel;

    private double similarity;

    private String question;

    private String dataSource;

    private String answer;

    private String ensembleFlag;

    // getter and setter

}

我的 JSON (jsonOutput)：

{  

   "sku":"4265252",

   "query":"\u8fd9\u6b3e\u662f\u5927\u4e00\u5339\u7684\u5440",

   "QAResponse":[  

      {  

         "answerLevel":"L1",

         "similarity":"1.217891",

         "question":"\u51e0\u5339\u7684",

         "dataSource":"knowledge",

         "ensembleFlag":"YES",

         "answer":"1\u5339\u7684"

      }

}

那为什么我的 JSON 对象映射器失败了呢？

ResponseList responseList = null;

if (jsonOutput != null) {

    ObjectMapper mapper = new ObjectMapper();

    try {

        responseList = mapper.readValue(jsonOutput, ResponseList.class);

    } catch (IOException io) {

        LOGGER.error(" json mapping to Java object failed!");

        io.printStackTrace();

    }

}

错误信息：

com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "QAResponse" (class com.jnlu.qe.model.ResponseList), not marked as ignorable (3 known properties: "query", "responses", "sku"])

 at [Source: (String)"{"sku": "4265252", "query": "\u8fd9\u6b3e\u662f\u5927\u4e00\u5339\u7684\u5440", "QAResponse": [{"answerLevel": "L1", "similarity": "1.217891", "question": "\u51e0\u5339\u7684", "dataSource": "knowledge", "ensembleFlag": "YES", "answer": "1\u5339\u7684"}, {"answerLevel": "L1", "similarity": "1.193976", "question": "\u8fd9\u4e2a\u662f\u51e0\u5339\u7684", "dataSource": "knowledge", "ensembleFlag": "YES", "answer": "\u8fd9\u6b3e\u662f1\u5339\u7684"}, {"answerLevel": "L1", "similarity": "1.179149", ""[truncated 8542 chars]; line: 1, column: 96] (through reference chain: com.jnlu.qe.model.ResponseList["QAResponse"])

Why doesn't the "QAResponse" not recognized?

Answer 1

它抛出异常，因为在 json 输入“QAResponse”属性中不存在。如果您不想将响应更改为类，请添加 @JsonProperty 注释。@JsonProperty(value = "QAResponse")private List<QAResponse> responses;

Answer 2

ResponseList类中的字段名称错误，而是：private&nbsp;List<QAResponse>&nbsp;responses;它应该是：private&nbsp;List<QAResponse>&nbsp;QAResponse;然而，QAResponse.answerLevel字段很可能是一个String除非AnswerLevel是一个枚举。

Answer 3

我认为这是因为在 JSON 中一个属性有一个名称，QAResponse但在一个类中它是一个responses.&nbsp;所以你必须让它们具有相同的名称