'no String-argument constructor/factory method to deserialize from String value
I am trying to make use of an external NYtimes API. Here is an sample example data output :
{
"status": "OK",
"copyright": "Copyright (c) 2016 The New York Times Company. All Rights Reserved.",
"section": "home",
"last_updated": "2016-10-20T19:57:45-04:00",
"num_results": 30,
"results": [{
"section": "Briefing",
"subsection": "",
"title": "Election, Dodgers, Duterte: Your Thursday Evening Briefing",
"abstract": "Here’s what you need to know at the end of the day.",
"url": "abc.co",
"byline": "By KAREN ZRAICK and MERRILL D. OLIVER",
"item_type": "Article",
"updated_date": "2016-10-20T18:32:41-04:00",
"created_date": "2016-10-20T17:58:30-04:00",
"published_date": "2016-10-20T17:58:30-04:00",
"material_type_facet": "",
"kicker": "",
"des_facet": [],
"org_facet": [],
"per_facet": [],
"geo_facet": [],
"multimedia": [{
"url": "abc.co",
"format": "Standard Thumbnail",
"height": 75,
"width": 75,
"type": "image",
"subtype": "photo",
"caption": "",
"copyright": "Damon Winter/The New York Times"
}, {
"url": "abc.co",
"format": "thumbLarge",
"height": 150,
"width": 150,
"type": "image",
"subtype": "photo",
"caption": "",
"copyright": "Damon Winter/The New York Times"
}, {
"url": "abc.co",
"format": "Normal",
"height": 127,
"width": 190,
"type": "image",
"subtype": "photo",
"caption": "",
"copyright": "Damon Winter/The New York Times"
}, {
"url": "abc.co",
"format": "mediumThreeByTwo210",
"height": 140,
"width": 210,
"type": "image",
"subtype": "photo",
"caption": "",
"copyright": "Damon Winter/The New York Times"
}, {
"url": "abc.co",
"format": "superJumbo",
"height": 1365,
"width": 2048,
"type": "image",
"subtype": "photo",
"caption": "",
"copyright": "Damon Winter/The New York Times"
}],
"short_url": "http://abc.co"
}
]
}
Here is the bean definition
//Headline.class
public class Headline {
@JsonProperty("status")
String status;
@JsonProperty("copyright")
String copyright;
@JsonProperty("section")
String section;
@JsonProperty("last_updated")
String last_updated;
@JsonProperty("num_results")
int num_results;
@JsonProperty("results")
List<Story> results;
`
//Story.class
@JsonProperty("section")
String section;
@JsonProperty("subsection")
String subsection;
@JsonProperty("title")
String title;
@JsonProperty("abstract")
String storyAbstract;
@JsonProperty("url")
String url;
@JsonProperty("byline")
String byline;
@JsonProperty("item_type")
String item_type;
@JsonProperty("updated_date")
String updated_date;
@JsonProperty("created_date")
String created_date;
@JsonProperty("published_date")
String published_date;
@JsonProperty("material_type_facet")
String material_type_facet;
@JsonProperty("kicker")
String kicker;
/*@JsonProperty("des_facet")
List des_facet;
@JsonProperty("org_facet")
List org_facet;
@JsonProperty("per_facet")
List per_facet;
@JsonProperty("geo_facet")
List geo_facet;*/
@JsonProperty("multimedia")
List<Media> multimedia;
@JsonProperty("short_url")
String short_url;
//Media.class
@JsonProperty("url")
String url;
@JsonProperty("format")
String format;
@JsonProperty("height")
int height;
@JsonProperty("width")
int width;
@JsonProperty("type")
String type;
@JsonProperty("subtype")
String subtype;
@JsonProperty("caption")
String caption;
@JsonProperty("copyright")
String copyright;
Here is my caller :
RestTemplate restTemplate = new RestTemplate();
MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
jsonConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("text","json",MappingJackson2HttpMessageConverter.DEFAULT_CHARSET)));
restTemplate.getMessageConverters().add(jsonConverter);
Headline headline = restTemplate.getForObject("http://abc/svc/topstories/v1/home.json?api-key=key",Headline.class);
logger.info("Headline"+headline.toString());
The exception now that I get when I make the call is :
Exception in thread "main" org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not construct instance of java.util.ArrayList: no String-argument constructor/factory method to deserialize from String value ('')
at [Source: java.io.PushbackInputStream@22d9d; line: 1, column: 1185] (through reference chain: NYTimes.Payload.Headline["results"]->java.util.ArrayList[0]->NYTimes.Story.Story["multimedia"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of java.util.ArrayList: no String-argument constructor/factory method to deserialize from String value ('')
at [Source: java.io.PushbackInputStream@22d9d; line: 1, column: 1185] (through reference chain: NYTimes.Payload.Headline["results"]->java.util.ArrayList[0]->NYTimes.Story.Story["multimedia"])
I've been trying to understand why it doesn't de-serialize. if the string value is empty - then it should result in an null list?
Solution 1:[1]
This exception is occurring because of the json response you are receiving -
{
"status": "OK",
"copyright": "Copyright (c) 2016 The New York Times Company. All Rights Reserved.",
"section": "home",
"last_updated": "2016-10-20T19:57:45-04:00",
"num_results": 30,
"results": [{
"section": "Briefing",
"subsection": "",
"title": "Election, Dodgers, Duterte: Your Thursday Evening Briefing",
"abstract": "Here’s what you need to know at the end of the day.",
"url": "abc.co",
"byline": "By KAREN ZRAICK and MERRILL D. OLIVER",
"item_type": "Article",
"updated_date": "2016-10-20T18:32:41-04:00",
"created_date": "2016-10-20T17:58:30-04:00",
"published_date": "2016-10-20T17:58:30-04:00",
"material_type_facet": "",
"kicker": "",
"des_facet": [],
"org_facet": [],
"per_facet": [],
"geo_facet": [],
"multimedia": "",
"short_url": "http://abc.co"
}
]
}
"multimedia" field is an empty string
So you need to verify your json and map you pojo accordingly.
Solution 2:[2]
This code is working.
Try to call your API with these objects.
I think you have naming issue in multimedia or something like that.
class Multimedia{
public String url;
public String format;
public int height;
public int width;
public String type;
public String subtype;
public String caption;
public String copyright;
@Override
public String toString() {
return String.format(
"Multimedia (url=%s, format=%s, height=%s, width=%s, type=%s, subtype=%s, caption=%s, copyright=%s)", this.url, this.format, this.height, this.width, this.type, this.subtype, this.caption, this.copyright);
}
}
class Result{
public String section;
public String subsection;
public String title;
@JsonProperty("abstract")
public String abstract2;
public String url;
public String byline;
public String item_type;
public Date updated_date;
public Date created_date;
public Date published_date;
public String material_type_facet;
public String kicker;
public List<Object> des_facet;
public List<Object> org_facet;
public List<Object> per_facet;
public List<Object> geo_facet;
public List<Multimedia> multimedia;
public String short_url;
@Override
public String toString() {
return String.format(
"Result (section=%s, subsection=%s, title=%s, abstract2=%s, url=%s, byline=%s, item_type=%s, updated_date=%s, created_date=%s, published_date=%s, material_type_facet=%s, kicker=%s, des_facet=%s, org_facet=%s, per_facet=%s, geo_facet=%s, multimedia=%s, short_url=%s)", this.section, this.subsection, this.title, this.abstract2, this.url, this.byline, this.item_type, this.updated_date, this.created_date, this.published_date, this.material_type_facet, this.kicker, this.des_facet, this.org_facet, this.per_facet, this.geo_facet, this.multimedia, this.short_url);
}
}
class Root{
public String status;
public String copyright;
public String section;
public Date last_updated;
public int num_results;
public List<Result> results;
@Override
public String toString() {
return String.format(
"Root (status=%s, copyright=%s, section=%s, last_updated=%s, num_results=%s, results=%s)", this.status, this.copyright, this.section, this.last_updated, this.num_results, this.results);
}
}
public class IAE {
public static void main(String[] args) throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
String json = "{\n" +
" \"status\": \"OK\",\n" +
" \"copyright\": \"Copyright (c) 2016 The New York Times Company. All Rights Reserved.\",\n" +
" \"section\": \"home\",\n" +
" \"last_updated\": \"2016-10-20T19:57:45-04:00\",\n" +
" \"num_results\": 30,\n" +
" \"results\": [{\n" +
" \"section\": \"Briefing\",\n" +
" \"subsection\": \"\",\n" +
" \"title\": \"Election, Dodgers, Duterte: Your Thursday Evening Briefing\",\n" +
" \"abstract\": \"Here’s what you need to know at the end of the day.\",\n" +
" \"url\": \"abc.co\",\n" +
" \"byline\": \"By KAREN ZRAICK and MERRILL D. OLIVER\",\n" +
" \"item_type\": \"Article\",\n" +
" \"updated_date\": \"2016-10-20T18:32:41-04:00\",\n" +
" \"created_date\": \"2016-10-20T17:58:30-04:00\",\n" +
" \"published_date\": \"2016-10-20T17:58:30-04:00\",\n" +
" \"material_type_facet\": \"\",\n" +
" \"kicker\": \"\",\n" +
" \"des_facet\": [],\n" +
" \"org_facet\": [],\n" +
" \"per_facet\": [],\n" +
" \"geo_facet\": [],\n" +
" \"multimedia\": [{\n" +
" \"url\": \"abc.co\",\n" +
" \"format\": \"Standard Thumbnail\",\n" +
" \"height\": 75,\n" +
" \"width\": 75,\n" +
" \"type\": \"image\",\n" +
" \"subtype\": \"photo\",\n" +
" \"caption\": \"\",\n" +
" \"copyright\": \"Damon Winter/The New York Times\"\n" +
" }, {\n" +
" \"url\": \"abc.co\",\n" +
" \"format\": \"thumbLarge\",\n" +
" \"height\": 150,\n" +
" \"width\": 150,\n" +
" \"type\": \"image\",\n" +
" \"subtype\": \"photo\",\n" +
" \"caption\": \"\",\n" +
" \"copyright\": \"Damon Winter/The New York Times\"\n" +
" }, {\n" +
" \"url\": \"abc.co\",\n" +
" \"format\": \"Normal\",\n" +
" \"height\": 127,\n" +
" \"width\": 190,\n" +
" \"type\": \"image\",\n" +
" \"subtype\": \"photo\",\n" +
" \"caption\": \"\",\n" +
" \"copyright\": \"Damon Winter/The New York Times\"\n" +
" }, {\n" +
" \"url\": \"abc.co\",\n" +
" \"format\": \"mediumThreeByTwo210\",\n" +
" \"height\": 140,\n" +
" \"width\": 210,\n" +
" \"type\": \"image\",\n" +
" \"subtype\": \"photo\",\n" +
" \"caption\": \"\",\n" +
" \"copyright\": \"Damon Winter/The New York Times\"\n" +
" }, {\n" +
" \"url\": \"abc.co\",\n" +
" \"format\": \"superJumbo\",\n" +
" \"height\": 1365,\n" +
" \"width\": 2048,\n" +
" \"type\": \"image\",\n" +
" \"subtype\": \"photo\",\n" +
" \"caption\": \"\",\n" +
" \"copyright\": \"Damon Winter/The New York Times\"\n" +
" }],\n" +
" \"short_url\": \"http://abc.co\"\n" +
" }\n" +
"\n" +
" ]\n" +
"}";
System.out.println(objectMapper.readValue(json,Root.class));
}
}
Output:
Root (status=OK, copyright=Copyright (c) 2016 The New York Times Company. All Rights Reserved., section=home, last_updated=Fri Oct 21 02:57:45 IDT 2016, num_results=30, results=[Result (section=Briefing, subsection=, title=Election, Dodgers, Duterte: Your Thursday Evening Briefing, abstract2=Here’s what you need to know at the end of the day., url=abc.co, byline=By KAREN ZRAICK and MERRILL D. OLIVER, item_type=Article, updated_date=Fri Oct 21 01:32:41 IDT 2016, created_date=Fri Oct 21 00:58:30 IDT 2016, published_date=Fri Oct 21 00:58:30 IDT 2016, material_type_facet=, kicker=, des_facet=[], org_facet=[], per_facet=[], geo_facet=[], multimedia=[Multimedia (url=abc.co, format=Standard Thumbnail, height=75, width=75, type=image, subtype=photo, caption=, copyright=Damon Winter/The New York Times), Multimedia (url=abc.co, format=thumbLarge, height=150, width=150, type=image, subtype=photo, caption=, copyright=Damon Winter/The New York Times), Multimedia (url=abc.co, format=Normal, height=127, width=190, type=image, subtype=photo, caption=, copyright=Damon Winter/The New York Times), Multimedia (url=abc.co, format=mediumThreeByTwo210, height=140, width=210, type=image, subtype=photo, caption=, copyright=Damon Winter/The New York Times), Multimedia (url=abc.co, format=superJumbo, height=1365, width=2048, type=image, subtype=photo, caption=, copyright=Damon Winter/The New York Times)], short_url=http://abc.co)])
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | developerick |
| Solution 2 |