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我试着从春天RestTemplate的东西。我试图读取这个JSON数据：JSON Data。数据是一个键值对，其中键是“geonames”，值是“geoname”对象的数组。RestTemplate：无法将对象的实例反序列化为START_OBJECT标记
我有一个Geoname类来处理输入。这个班级里还有getter和setter。然后，我有只运行一个主要方法调用RestTemplate对象app类：
@JsonIgnoreProperties(ignoreUnknown = true)
public class Geoname {
private String name;
private long lat;
private long lng;
private String countrycode;
}
App.java
public class App
{
public static void main(String[] args)
{
String jsonUrl = "http://api.geonames.org/citiesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&lang=de&username=demo";
RestTemplate template = new RestTemplate();
ResponseEntity<Geoname[]> entity = template.getForEntity(jsonUrl, Geoname[].class);
List<Geoname> data = Arrays.asList(entity.getBody());
System.out.print("Success!");
}
}
这是我的错误输出：
Exception in thread "main" org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of com.declan.Geoname[] out of START_OBJECT token
at [Source: [email protected]3ac5; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of com.declan.Geoname[] out of START_OBJECT token
at [Source: [email protected]3ac5; line: 1, column: 1]
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:208)
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:200)
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:96)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:812)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:796)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:576)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:529)
at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:261)
at com.declan.App.main(App.java:20)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of com.declan.Geoname[] out of START_OBJECT token
at [Source: [email protected]3ac5; line: 1, column: 1]
at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148)
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:835)
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:831)
at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.handleNonArray(ObjectArrayDeserializer.java:232)
at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:139)
at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:17)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3560)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2660)
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:205)
... 13 more
我已经尝试过这种设置，我试着使用getForObject就像在春天的文档，我已经尝试在这里搜索stackoverflow和使用映射到列表的常见问题。我甚至尝试创建一个仅包含数组或Geoname对象的Geonames类，但这种方法也无法正常工作......始终存在相同的错误。也许，我没有正确阅读Json，但如果有人能借给我一双眼睛，我会很感激。 ：D
干杯！
编辑
好吧，我现在有这个新的类，它现在做的JSON数据的GET请求。但是，在调试之后，ResponseEntity主体将数组设置为null。我是否需要手动实例化Geonames中的数组？
@JsonIgnoreProperties(ignoreUnknown = true)
public class Geonames {
@JsonProperty("geonames")
Geoname[] geonames;
public void setGeonames(Geonames[] geonames) {
this.geonames = geonames;
}
public void getGeonames() {
return geonames;
}
}