问题
I work with websecrpits and I want to create an object from my JSON. I use RestTemplate to do that :
MetaData entity = restTemplate.postForObject(url + "?alf_ticket={ticket}", requestEntity, MetaData.class, _ticket);
but the problem is that I got this error :
Exception in thread "main" org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: No suitable constructor found for type [simple type, class custom.alfresco.logic.connect.models.MetaData$Item]: can not instantiate from JSON object (need to add/enable type information?)
at [Source: sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@756de23f; line: 7, column: 5] (through reference chain: custom.alfresco.logic.connect.models.MetaData["data"]->custom.alfresco.logic.connect.models.Data["items"]); nested exception is org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type [simple type, class custom.alfresco.logic.connect.models.MetaData$Item]: can not instantiate from JSON object (need to add/enable type information?)
at [Source: sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@756de23f; line: 7, column: 5] (through reference chain: custom.alfresco.logic.connect.models.MetaData["data"]->custom.alfresco.logic.connect.models.Data["items"])
at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readJavaType(MappingJacksonHttpMessageConverter.java:187)
at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.read(MappingJacksonHttpMessageConverter.java:179)
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:549)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:502)
at org.springframework.web.client.RestTemplate.postForObject(RestTemplate.java:330)
at com.custom.alfresco.templates.postTemplate.postObjectResponse(postTemplate.java:112)
at custom.alfresco.logic.connect.RepositoryOperation.getMetadata(RepositoryOperation.java:617)
at custom.alfresco.UI.main.main(main.java:35)
My class MetaData is like the following :
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({ "data" })
public class MetaData extends CommunicationObject {
@JsonProperty("data")
private Data data;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
@JsonProperty("data")
public Data getData() {
return data;
}
@JsonProperty("data")
public void setData(Data data) {
this.data = data;
}
@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({ "items" })
public class Data {
@JsonProperty("items")
private List<Item> items = new ArrayList<Item>();
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
@JsonProperty("items")
public List<Item> getItems() {
return items;
}
@JsonProperty("items")
public void setItems(List<Item> items) {
this.items = items;
}
@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
}
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({ "type", "parentType", "isContainer", "name", "title", "description", "modified", "modifier",
"displayPath", "nodeRef" })
public class Item {
@JsonProperty("type")
private String type;
@JsonProperty("parentType")
private String parentType;
@JsonProperty("isContainer")
private Boolean isContainer;
@JsonProperty("name")
private String name;
@JsonProperty("title")
private String title;
@JsonProperty("description")
private String description;
@JsonProperty("modified")
private String modified;
@JsonProperty("modifier")
private String modifier;
@JsonProperty("displayPath")
private String displayPath;
@JsonProperty("nodeRef")
private String nodeRef;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
@JsonProperty("type")
public String getType() {
return type;
}
@JsonProperty("type")
public void setType(String type) {
this.type = type;
}
@JsonProperty("parentType")
public String getParentType() {
return parentType;
}
@JsonProperty("parentType")
public void setParentType(String parentType) {
this.parentType = parentType;
}
@JsonProperty("isContainer")
public Boolean getIsContainer() {
return isContainer;
}
@JsonProperty("isContainer")
public void setIsContainer(Boolean isContainer) {
this.isContainer = isContainer;
}
@JsonProperty("name")
public String getName() {
return name;
}
@JsonProperty("name")
public void setName(String name) {
this.name = name;
}
@JsonProperty("title")
public String getTitle() {
return title;
}
@JsonProperty("title")
public void setTitle(String title) {
this.title = title;
}
@JsonProperty("description")
public String getDescription() {
return description;
}
@JsonProperty("description")
public void setDescription(String description) {
this.description = description;
}
@JsonProperty("modified")
public String getModified() {
return modified;
}
@JsonProperty("modified")
public void setModified(String modified) {
this.modified = modified;
}
@JsonProperty("modifier")
public String getModifier() {
return modifier;
}
@JsonProperty("modifier")
public void setModifier(String modifier) {
this.modifier = modifier;
}
@JsonProperty("displayPath")
public String getDisplayPath() {
return displayPath;
}
@JsonProperty("displayPath")
public void setDisplayPath(String displayPath) {
this.displayPath = displayPath;
}
@JsonProperty("nodeRef")
public String getNodeRef() {
return nodeRef;
}
@JsonProperty("nodeRef")
public void setNodeRef(String nodeRef) {
this.nodeRef = nodeRef;
}
@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
}
}
And the JSON that I'm trying to parse is the following :
{"data":
{
"items":
[
{
"type": "cm:content",
"parentType": "cm:cmobject",
"isContainer": false,
"name": "second.alf",
"title": "",
"description": "",
"modified": "2014-07-01T16:21:10.712+02:00",
"modifier": "admin",
"displayPath": "\/Espace racine\/Alfredine\/Custom saved documents",
"nodeRef": "workspace://SpacesStore/6f8ebd09-f7bf-4967-9fc5-a90a9d825088"
}
]
}
}
What's wrong with my class ? it says that no suitable constructor for type Item. I tried to add a constructor the Item class but I still get the same Error. Any one to Help ?
回答1:
Found It !!. The solution is quite strange actually. The problem comes from the inner classes. The old structure was like this :
public class MetaData{
...
public class Data {
....
public class Item{
...
}
}
}
The inner classes has to be static because there is no way Jackson can instantiate directly an inner class. For more details go HERE. So what I did is:
public class MetaData{
...
static class Data {
....
static class Item{
...
}
}
}
Everything worked just fine. Hope that helped !
回答2:
thank you everyone,I hava found answer in this questuin.Fail filling object from JSON with RestTemplate
Found It !!. The solution is quite strange actually. The problem comes from the inner classes. The old structure was like this :
public class MetaData{
...
public class Data {
....
public class Item{
...
}
}
}
The inner classes has to be static because there is no way Jackson can instantiate directly an inner class. For more details go HERE. So what I did is:
public class MetaData{
...
static class Data {
....
static class Item{
...
}
}
}
Everything worked just fine. Hope that helped !
shareedit
answered Jul 9 '14 at 10:04
deltascience
1,12312048
add a comment
ok
来源：https://stackoverflow.com/questions/24650167/fail-filling-object-from-json-with-resttemplate