[英]Deserializing JSON array of objects using GSON
This is one in a row of deserialization questions but I've read them all and can't figure out the solution for my problem. 这是反序列化问题中的一连串问题,但是我已经阅读了所有问题,无法解决我的问题的解决方案。
I need to get all the "entery"->"content" ->$t and "entery"->"title"->"$t" but in CategoryDeserializer() I get JsonArray that is NULL. 我需要获取所有的“ entery”->“ content”-> $ t和“ entery”->“ title”->“ $ t”,但是在CategoryDeserializer()中,我得到的JsonArray为NULL。 I've pointed to that part of the code with "<====".
我已经用“ <====“指向了代码的这一部分。
Error message: 错误信息:
Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference
尝试在空对象引用上调用接口方法'java.util.Iterator java.util.List.iterator()'
I have JSON that looks something like this: 我有看起来像这样的JSON:
{ "feed":{
"id":{ ... },
"author":[ ... ],
"entry":[
{
"id":{ },
"updated":{ },
"category":[ ],
"title":{
"type":"text",
"$t":"A1 },
"content":{
"type":"text",
"$t":"test"
},
"link":[ ]
},
{ ... },
{ ... },
{ ...},
]
}
}
This is part of my code where I try to deserialize "entery": 这是我尝试反序列化“ entery”的代码的一部分:
String json = response.body().toString();
Type listType = new TypeToken<List<Entry>>() {
}.getType();
Gson gson = new GsonBuilder().registerTypeAdapter(listType, new CategoryDeserializer()).create();
List<Entry> list = gson.fromJson(json, listType);
for (Entry entry : list) {
Log.i("MainActivity", "Content: " + entry.getContent());}
Where CategoryDeserializer() looks like this: 其中CategoryDeserializer()如下所示:
public class CategoryDeserializer implements JsonDeserializer<List<Entry>> {
public List<Entry> deserialize(JsonElement je, Type type, JsonDeserializationContext jdc) throws JsonParseException {
JsonArray entry = je.getAsJsonObject().getAsJsonArray("entry"); //<==== here I get that entry is null but je has a value
ArrayList<Entry> myList = new ArrayList<Entry>();
for (JsonElement e : entry) {
myList.add((Entry) jdc.deserialize(e, Entry.class));
}
return myList;}
And my Entry class: 我的入门班:
public class Entry {
private Id_ id;
private Updated_ updated;
private List<Category_> category = null;
private Title_ title;
private Content content;
private List<Link_> link = null;
//getters and setters
public Id_ getId() {
return id;
}
public void setId(Id_ id) {
this.id = id;
}
public Updated_ getUpdated() {
return updated;
}
public void setUpdated(Updated_ updated) {
this.updated = updated;
}
public List<Category_> getCategory() {
return category;
}
public void setCategory(List<Category_> category) {
this.category = category;
}
public Title_ getTitle() {
return title;
}
public void setTitle(Title_ title) {
this.title = title;
}
public Content getContent() {
return content;
}
public void setContent(Content content) {
this.content = content;
}
public List<Link_> getLink() {
return link;
}
public void setLink(List<Link_> link) {
this.link = link;
}
}
Edit: I have declaration and instantiation. 编辑:我有声明和实例化。
I was complicating things that were not complicated. 我使事情复杂化了。 All I had to do was this:
我所要做的就是:
String json = response.body().toString();
Gson mGson = new Gson();
//where Example is the root of JSON
Example rsp = mGson.fromJson(json, Example.class);
//Entry is the list I needed to access
List <Entry> listOfEntrys= rsp.getFeed().getEntry();
//get value
Log.i("MainActivity", "listaEntrya " + listOfEntrys.get(0).getTitle().get$t());
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