Java 为什么jsonParser.getCodec().readTree(jsonParser.asText()为我返回一个空字符串?
我编写了一个REST服务来接收post请求中的元数据。我使用的是spring data elasticsearch,我创建了一个自定义元数据对象,将Json反序列化为如下所示:Java 为什么jsonParser.getCodec().readTree(jsonParser.asText()为我返回一个空字符串?,java,json,spring,rest,post,Java,Json,Spring,Rest,Post,我编写了一个REST服务来接收post请求中的元数据。我使用的是spring data elasticsearch,我创建了一个自定义元数据对象,将Json反序列化为如下所示: @Document(indexName = "metadata_v1", type = "metadata") public class Metadata { @Id private String id; @Field(type = FieldType.String) privat
@Document(indexName = "metadata_v1", type = "metadata")
public class Metadata {
@Id
private String id;
@Field(type = FieldType.String)
private String uuid;
@Field(type = FieldType.String)
private String userId;
@Field(type = FieldType.Date, format = DateFormat.basic_date_time)
private Date date = null;
@Field(type = FieldType.String)
private String classification;
@Field(type = FieldType.Nested)
private List<NumericKeyValue> numericKeyValue;
@Field(type = FieldType.Nested)
private List<TextKeyValue> textKeyValue;
public class NumericKeyValueJsonDeserializer extends JsonDeserializer<List<NumericKeyValue>>{
@Override
public List<NumericKeyValue> deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
TypeReference<List<NumericKeyValue>> typeRef = new TypeReference<List<NumericKeyValue>>(){};
ObjectMapper mapper = new ObjectMapper();
JsonNode root = jp.getCodec().readTree(jp);
String numericKeyValue = root.get("numericKeyValue").asText();
return mapper.readValue( numericKeyValue, typeRef);
}
}
"numericKeyValue" : {
"type" : "nested",
"properties" : {
"key" : {"type" : "string"},
"value" : {"type" : "double"}
}
}
我补充说
@JsonDeserialize(using = NumericKeyValueJsonDeserializer.class)
到我的元数据类中的字段声明
然而,经过大量测试,我逐渐意识到JsonNode根
不仅不包含“numericKeyValue”
,而且在调用根.asText()时,它会给我一个完全空的字符串
我一直在使用Postman向我的端点发送post请求
@RequestMapping(value="/metadata_v1/ingest", method=RequestMethod.POST, consumes="application/json")
public @ResponseBody Metadata createEntry(@RequestBody Metadata entry){
repository.save(entry);
return entry;
}
包含以下Json:
{
"numericKeyValue":
[
{
"key": "velocity",
"value": 55.5
},
{
"key": "angle",
"value": 90
}
]
}
我的映射如下所示:
@Document(indexName = "metadata_v1", type = "metadata")
public class Metadata {
@Id
private String id;
@Field(type = FieldType.String)
private String uuid;
@Field(type = FieldType.String)
private String userId;
@Field(type = FieldType.Date, format = DateFormat.basic_date_time)
private Date date = null;
@Field(type = FieldType.String)
private String classification;
@Field(type = FieldType.Nested)
private List<NumericKeyValue> numericKeyValue;
@Field(type = FieldType.Nested)
private List<TextKeyValue> textKeyValue;
public class NumericKeyValueJsonDeserializer extends JsonDeserializer<List<NumericKeyValue>>{
@Override
public List<NumericKeyValue> deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
TypeReference<List<NumericKeyValue>> typeRef = new TypeReference<List<NumericKeyValue>>(){};
ObjectMapper mapper = new ObjectMapper();
JsonNode root = jp.getCodec().readTree(jp);
String numericKeyValue = root.get("numericKeyValue").asText();
return mapper.readValue( numericKeyValue, typeRef);
}
}
"numericKeyValue" : {
"type" : "nested",
"properties" : {
"key" : {"type" : "string"},
"value" : {"type" : "double"}
}
}
如果需要,我可以展示更多的东西。我想如果我能以某种方式获得用Java发送的JSON,也许是作为字符串,我会很好。我一直在获取导致空指针异常的空字符串,当我尝试String numericKeyValue=jp.getText()
时,该字符串只是“[”的当前标记,我想它至少不是空字符串,但仍然对我没有帮助
非常感谢您的帮助或建议。在您的情况下,numericKeyValue
的值是一个数组。您应该替换以下行:
String numericKeyValue = root.get("numericKeyValue").asText();
与: