Android 无法从 Spring 3 REST Web 服务中的 START_ARRAY 令牌反序列化对象实例
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Cannot deserialize instance of object out of START_ARRAY token in Spring 3 REST Webservice
提问by Gabriela Radu
I am making use of this cool thing Spring offers: Spring RESTWebService (Version of spring is 3). If I access the URL from browser I can see the JSON response, but from a Client endpoint (Android application) iIreceive this error message:
我正在利用 Spring 提供的这个很酷的东西：Spring RESTWebService（spring 的版本是 3）。如果我从浏览器访问 URL，我可以看到 JSON 响应，但是从客户端端点（Android 应用程序）接收到此错误消息：
Caused by: org.springframework.web.client.ResourceAccessException:
I/O error: Can not deserialize instance of MyObject out of START_ARRAY token
at [Source: org.apache.http.conn.EofSensorInputStream@4076e940; line: 1,
column: 1]; nested exception is org.codehaus.Hymanson.map.JsonMappingException:
Can not deserialize instance of MyObject out of START_ARRAY token
at [Source: org.apache.http.conn.EofSensorInputStream@4076e940; line: 1, column: 1]
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:466)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:414)
at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:234)
at com.be.android.locateconsultants.resources.AsyncTaskRESTServiceCaller.doInBackground(AsyncTaskRESTServiceCaller.java:43)
at com.be.android.locateconsultants.resources.AsyncTaskRESTServiceCaller.doInBackground(AsyncTaskRESTServiceCaller.java:1)
at android.os.AsyncTask.call(AsyncTask.java:252)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
... 4 more
Caused by: org.codehaus.Hymanson.map.JsonMappingException: Can not deserialize
instance of MyObject out of START_ARRAY token
at [Source: org.apache.http.conn.EofSensorInputStream@4076e940; line: 1, column: 1]
at org.codehaus.Hymanson.map.deser.StdDeserializationContext.mappingException(StdDeserializationContext.java:198)
at org.codehaus.Hymanson.map.deser.BeanDeserializer.deserializeUsingCreator(BeanDeserializer.java:565)
at org.codehaus.Hymanson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:365)
at org.codehaus.Hymanson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2395)
at org.codehaus.Hymanson.map.ObjectMapper.readValue(ObjectMapper.java:1655)
at org.springframework.http.converter.json.MappingHymansonHttpMessageConverter.readInternal(MappingHymansonHttpMessageConverter.java:135)
at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:154)
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:74)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:632)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:618)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:459)
... 10 more
MyObject structure is the same as the one from the server side application.
MyObject 结构与来自服务器端应用程序的结构相同。
I have tried to request the server like this:
我试图像这样请求服务器：
final String url = ".....";
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<Consultant> responseEntity = restTemplate.getForEntity(
url, Consultant.class);
Or like this:
或者像这样：
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> entity = new HttpEntity<String>(headers);
ResponseEntity<MyObject> response = restTemplate
.exchange("....",HttpMethod.GET, entity, MyObject.class);
System.out.println("RESPONSE: " + response.getBody());
But still the same error as above. Can't figure out what I am missing at this point, any idea or hints would be great. Thank you.
但是还是和上面一样的错误。目前无法弄清楚我缺少什么，任何想法或提示都会很棒。谢谢你。
采纳答案by Ahto Luuri
Solution in a similar situation was to map to Consultant[].classThis applies if you try to deserialize a JSON array of your mapped objects.
类似情况下的解决方案是映射到Consultant[].class如果您尝试反序列化映射对象的 JSON 数组，则此方法适用。
回答by pawelzieba
You should map it to List<Consultant>rather than to Consultant.class.
您应该将其映射到List<Consultant>而不是Consultant.class.
回答by NathanChristie
This is related to Hymanson and the way you're attempting to deserialize and initialize a container from an array.
这与 Hymanson 以及您尝试从数组反序列化和初始化容器的方式有关。
While my usage context is a bit different, this may help some who get here from searching for Hymanson-specific deserialization errors.
虽然我的使用上下文有点不同，但这可能会帮助一些人通过搜索 Hymanson 特定的反序列化错误到达这里。
I had to do it like this:
我不得不这样做：
List<Consultant> consultants = Arrays.asList(
mapper.readValue(myJson.toString(), Consultants[].class)
);
回答by Tiina
a file foo.json contains a batch of data like this:
文件 foo.json 包含一批这样的数据：
[{"A":"TYMH","B":"datab","C":"DLJQ","D":"datad"}, {"A":"TYMH","B":"datab","C":"DLJQ","D":"datad"}]
[{"A":"TYMH","B":"datab","C":"DLJQ","D":"datad"}, {"A":"TYMH","B":"datab ","C":"DLJQ","D":"datad"}]
The following statement gives you an ArrayList of LinkedHashMap, where A B C D are the keys.
以下语句为您提供 LinkedHashMap 的 ArrayList，其中 ABCD 是键。
List list = mapper.readValue(new File("D:\...\foo.json"), List.class);
