从嵌套的 JSON 字符串中获取特定键的值

Question

在这里，我有一个后映射类型的控制器。 我将请求正文作为嵌套 JSON 的字符串。 当使用字符串作为请求主体调用控制器时，我想将该字符串映射到 POJO。 在那个 POJO 中，我有要从嵌套的 json 映射的字段，还有一个字段，它按原样获取实际的 String 请求主体。 请帮助我如何将特定字段从嵌套的 json 字符串映射到 POJO。

请求看起来像 -

{
    "Application": {
        "DCode": "unsecliverelease",
        "PType": "DA",
        "AId": "230391106",
        "ApNO": "NTFLbjOF9fXI15AF1YiC",
        "crd": {
            "cate": "lion",
            "ProductCode": "lion"
        },
        "ld": {
            "dm": {
                "sn": "3",
                "RandomNumbers": {
                    "RandomNumber01": "319",
                    "RandomNumber02": "731",
                    "RandomNumber03": "520",
                    "RandomNumber04": "102",
                    "RandomNumber05": "678"
                },
                "Request": {
                    "Name": "MSE",
                    "ACount": "1",
                    "BrandInd": "wert",
                    "CID": "123456789",
                    
                }
            }
    }

//控制器

@PostMapping(
      value = "/decision",
      produces = MediaType.APPLICATION_JSON_VALUE,
      consumes = MediaType.APPLICATION_JSON_VALUE)
  public ResponseEntity<crdResponse > getDecision(
      @RequestBody final @Valid String request) throws JsonProcessingException {
    crdResponse response =
        crdService.getDec(request);

    return ResponseEntity.ok().body(response);
  }

//POJO

public class CRequestModel {

  @Column(name = "rid")
  @Id
  private String crdRqsId;

  @Column(name = "scode")
  private String scode;

  @Column(name = "cid")
  private Integer cid;

  @Column(name = "RequestNumber")
  private Integer requestNumber;

  @Column(name = "RequestJson")
  private String requestJSON;

  @Column(name = "CreatedAt")
  private Timestamp createdAt;
}

我想将整个 JSON 字符串保存到 requestJSON 字段中，并希望将 CID 值（来自请求 JSON STRING）保存到 cid 字段中。

请帮助我。 此输入 JSON 字符串可以更改，因此 CID 在当前 JSON 字符串中的顺序可能会有所不同。

Answer 1

您发布的 Json 无效。 我想它应该是这样的：

{
  "Application": {
    "DCode": "unsecliverelease",
    "PType": "DA",
    "AId": "230391106",
    "ApNO": "NTFLbjOF9fXI15AF1YiC",
    "crd": {
      "cate": "lion",
      "ProductCode": "lion"
    },
    "ld": {
      "dm": {
        "sn": "3",
        "RandomNumbers": {
          "RandomNumber01": "319",
          "RandomNumber02": "731",
          "RandomNumber03": "520",
          "RandomNumber04": "102",
          "RandomNumber05": "678"
        },
        "Request": {
          "Name": "MSE",
          "ACount": "1",
          "BrandInd": "wert",
          "CID": "123456789"
        }
      }
    }
  }
}

您可以执行以下操作：

String json ="{\n" +
                     "  \"Application\": {\n" +
                     "    \"DCode\": \"unsecliverelease\",\n" +
                     "    \"PType\": \"DA\",\n" +
                     "    \"AId\": \"230391106\",\n" +
                     "    \"ApNO\": \"NTFLbjOF9fXI15AF1YiC\",\n" +
                     "    \"crd\": {\n" +
                     "      \"cate\": \"lion\",\n" +
                     "      \"ProductCode\": \"lion\"\n" +
                     "    },\n" +
                     "    \"ld\": {\n" +
                     "      \"dm\": {\n" +
                     "        \"sn\": \"3\",\n" +
                     "        \"RandomNumbers\": {\n" +
                     "          \"RandomNumber01\": \"319\",\n" +
                     "          \"RandomNumber02\": \"731\",\n" +
                     "          \"RandomNumber03\": \"520\",\n" +
                     "          \"RandomNumber04\": \"102\",\n" +
                     "          \"RandomNumber05\": \"678\"\n" +
                     "        },\n" +
                     "        \"Request\": {\n" +
                     "          \"Name\": \"MSE\",\n" +
                     "          \"ACount\": \"1\",\n" +
                     "          \"BrandInd\": \"wert\",\n" +
                     "          \"CID\": \"123456789\"\n" +
                     "        }\n" +
                     "      }\n" +
                     "    }\n" +
                     "  }\n" +
                     "}";
    
    

CRequestModel cRequestModel = new CRequestModel();
    cRequestModel.setRequestJSON(json);

    ObjectMapper mapper = new ObjectMapper();
    JsonNode actualObj = mapper.readTree(json);
    JsonNode cidNode = actualObj.get("Application").get("ld").get("dm").get("Request").get("CID");
    int cid= mapper.treeToValue(cidNode,Integer.class);
    cRequestModel.setCid(cid);

注意：假设您获得的 json 将始终具有上述结构和属性：ld、dm、Request、CID。 （顺序无关紧要）

Answer 2

如果您有可以更改的 JSON 字符串，我认为您必须创建一个将该 JSON 字符串解析为jsonobject的方法，然后从指定的“键”中提取一个值。

例如，如果您有一个如此组合的 JSON 字符串，

{
 "name":"Sam", 
 "surname":"Baudo"
}

String jsonStringInput = "input-json-value"; 
JSONObject json = new JSONObject(jsonStringInput);
String surname = json.getString("surname");