我使用websecrpits，我想从我的JSON创建一个对象。我使用RestTemplate来做到这一点：
MetaData entity = restTemplate.postForObject(url + "?alf_ticket={ticket}", requestEntity, MetaData.class, _ticket);
但问题是我收到了这个错误：
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)
我的班级MetaData如下所示：
@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);
}
}
}
我试图解析的JSON如下：
{"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"
}
]
}
}
我的班级出了什么问题？它说类型Item没有合适的构造函数。我试图添加Item类的构造函数，但我仍然得到相同的错误。有人帮忙吗？
答案 0 :(得分：0)
发现它!!实际上解决方案很奇怪。问题来自内部阶级。旧结构是这样的：
public class MetaData{
...
public class Data {
....
public class Item{
...
}
}
}
内部类必须是静态的，因为Jackson无法直接实例化内部类。有关详细信息，请转到HERE。所以我做的是：
public class MetaData{
...
static class Data {
....
static class Item{
...
}
}
}
一切都很好。希望有所帮助！
答案 1 :(得分：0)
谢谢大家，我已经在此问题中找到答案。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 !
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answered Jul 9 '14 at 10:04
deltascience
1,12312048
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ok