Question

从服务调用API请求时，出现以下错误：

org.springframework.http.converter.HttpMessageNotReadableException: 
JSON parse error: Cannot deserialize instance of `java.lang.String` out of 
START_OBJECT token; nested exception is 
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize 
instance of `java.lang.String` out of START_OBJECT token
 at [Source: (ByteArrayInputStream); line: 19, column: 30] (through reference chain: java.lang.Object[][0]->com.cellwize.network.mo.load.model.ManagedObject["a"]->java.util.LinkedHashMap["siPeriodicity"])

我想要获取的json是：

[ {
  "guid" : "e_guid_lncell:311|480|6535681",
  "uid" : "c3528280-0d50-3ad8-a5be-d2dbdfcb77fd",
  "parentUid" : "0306573b-e431-37ad-ae59-5435947548cf",
  "parentMoClass" : null,
  "originalId" : "025530_1",
  "metaType" : "sector",
  "vendor" : "e",
  "technology" : "4g",
  "references" : null,
  "updateCommandType" : null,
  "scopeId" : "f5ed648f-4b42-4033-9243-db2150840995",
  "snapshotId" : 2054717834413232,
  "base_key" : "025530_1;MC",
  "class" : "vsDataEUtranCellFDD",
  "a" : {
    "prsConfigIndexMapped" : "1",
    "siPeriodicity" : {
      "siPeriodicitySI1" : "16",
      "siPeriodicitySI10" : "64",
      "siPeriodicitySI2" : "64",
      "siPeriodicitySI3" : "64",
      "siPeriodicitySI4" : "64",
      "siPeriodicitySI5" : "64",
      "siPeriodicitySI6" : "64",
      "siPeriodicitySI7" : "64",
      "siPeriodicitySI8" : "64",
      "siPeriodicitySI9" : "64"
    }
  }
} ]

请求API调用的函数是：

    public Map<String, ManagedObject> mapMosToUids(Collection<String> uids) throws IOException {
        if (uids == null || uids.isEmpty()) {
            return Collections.emptyMap();
        }

        final String url = naasUrl + "/getMos/" + String.join(",", uids);
        ResponseEntity<ManagedObject[]> response = restTemplate.getForEntity(url, ManagedObject[].class);


        ManagedObject[] mos = response.getBody();
        return Arrays.stream(mos).collect(Collectors.toMap(mo -> mo.getUid().toString(), mo -> mo));
    }

该课程的Pojo是：


@JsonIgnoreProperties({"_id"})
public class ManagedObject{
    public static final String ATTRIBUTES_PREFIX = "a";
    public static final String GEN_ATTRIBUTES_PREFIX = "gen";
    public static final String PHY_ATTRIBUTES_PREFIX = "phy";
    public static final String BIT_ATTRIBUTES_PREFIX = "bit";

    public static final String META_PREFIX = "meta";
    public static final String CLASS_COLUMN = "class";
    public static final String BASEKEY_COLUMN = "base_key";
    public static final String NET_CTRL_KEY = "net_ctrl_uid";
    public static final String NETWORK_CONTROLLER = "netCtrl";
    public static final String META_TYPE_COLUMN = "meta_type";
    public static final String GUID_COLUMN = "guid";
    public static final String UID_COLUMN = "uid";
    public static final String PARENT_UID_COLUMN = "parent_uid";

    private static final StringDeduplicator STRING_DEDUPLICATOR = new StringDeduplicator();

    private String guid;
    private UUID uid;
    private UUID parentUid;
    private String parentMoClass;
    private String originalId;
    @JsonProperty(BASEKEY_COLUMN)
    private String originalName;
    @JsonProperty(CLASS_COLUMN)
    private String moClass;
    private String metaType;
    private String vendor;
    private String technology;
    @JsonProperty(ATTRIBUTES_PREFIX)
    private Map<IgnoredCaseKey, Object> attributes;
    private Map<String, String> references;
    @JsonProperty(META_PREFIX)
    private Map<String, String> meta;
    @JsonProperty(GEN_ATTRIBUTES_PREFIX)
    private Map<String, String> genAttributes;
    private String updateCommandType;

    @JsonProperty(PHY_ATTRIBUTES_PREFIX)
    private Map<String,String> phyAttributes;
    private UUID scopeId;
    private Long snapshotId;

    public ManagedObject() {
        this.attributes = new HashMap<>();
        this.meta = new HashMap<>();
        this.genAttributes = new HashMap<>();
        this.phyAttributes = new HashMap<>();
    }

    public ManagedObject(UUID uid, UUID parentUid, String moClass, Map<String, String> attributes) {
        this();

        this.uid = uid;
        this.parentUid = parentUid;
        this.moClass = moClass;

        copyAttributes(attributes, this.attributes);
    }
}```

我尝试编写自己的JsonDeserialize，但没有用。如果我在getForEntity中获得一个对象并由我自己使用ObjectMapper反序列化，则该过程会逐步运行，但最终会起作用，但我正在寻找更好的解决方案

Answer 1

无法反序列化java.lang.String的实例 START_OBJECT令牌；

此异常表示您搞砸了Jackson映射。

我为简化调试的个人建议是，在处理复杂的JSON结构时，请尝试逐步进行操作，而不是立即映射整个结构。从第一层开始，越来越深入地逐步揭示JsonNodes。

错误很可能在这里，因为IgnoredCaseKey不是字符串，而是自定义对象。尝试将attributes或a键值对声明为JsonNode，然后向下走以查找导致错误的原因。

因此，您的第一步就是要替换它：

@JsonProperty(ATTRIBUTES_PREFIX)
private Map<IgnoredCaseKey, Object> attributes;

与此：

@JsonProperty(ATTRIBUTES_PREFIX)
private JsonNode attributes;

如果这没有引起任何错误，则问题在于此Map<IgnoredCaseKey, Object>是给定JSON对象的错误类型。如果确实导致错误，则问题出在其他地方。

由于您提供的JSON的结构不准确，因此我无法为您提供具体的答案，但希望该指导将有助于您更有效地进行故障排除。

从Spring RestTemplate反序列化Map <IgnoredCaseKey，Object>响应时出错

1 个答案: