[英]How to deserialize this json with Gson?
我将使用Gson
反序列化此json string
{
"ads": [
{
"ad": {
"id": 1,
"title": "...",
"publicImage": "...",
"publicUrl": "...",
"adposition": {
"name": "home"
},
"ttl": 30,
"debug": false
}
},
{
"ad": {
"id": 2,
"title": "...",
"publicImage": "...",
"publicUrl": "...",
"adposition": {
"name": "splash"
},
"ttl": 30,
"debug": false
}
},
{
"ad": {
"id": 3,
"title": "...",
"publicImage": "...",
"publicUrl": "...",
"adposition": {
"name": "home"
},
"ttl": 30,
"debug": false
}
}
],
"message": "issue list generated",
"status": "success"
}
我为类创建的是(已删除getter setter):
public class Ad {
public class AdPosition{
private String mName;
public String getName() {
return mName;
}
public void setName(String name) {
mName = name;
}
}
@SerializedName("id")
private int mID;
@SerializedName("title")
private String mTitle;
@SerializedName("publicImage")
private String mPublicImage;
@SerializedName("publicUrl")
private String mPublicUrl;
@SerializedName("ttl")
private int mTtl;
@SerializedName("adposition")
private AdPosition mAdPosition;
}
和
public class AdsListResponse {
@SerializedName("ads")
private List<Ad> mAds;
@SerializedName("message")
private String mMessage;
@SerializedName("status")
private String mStatus;
}
对于转换,我使用下面的代码
Gson gson = new GsonBuilder().setPrettyPrinting().create();
AdsListResponse ads = gson.fromJson(response, AdsListResponse.class);
for(Ad ad : ads.getAds()){
if(ad.getAdPosition().getName().equalsIgnoreCase("splash")){
System.out.println(ad.getAdPosition().getName());
}
但是我的列表包含objects(Ad),但它们的每个字段均为空,例如,它有3个广告,但id,title,...全部为null,我该怎么办?
抱歉,我复制并粘贴错误,但是问题仍然存在,我的广告列表包含广告,但广告的每个字段都为空
让我们分析一下您的JSON
{ // an object at the root
"ads": [ // a key value pair, where the value is an array
{ // an object within the array
"ad": { // a key value pair, where the value is an object
// bunch of key value pairs, with int, string, boolean or object values
"id": 1,
"title": "...",
"publicImage": "...",
"publicUrl": "...",
"adposition": {
"name": "home"
},
"ttl": 30,
"debug": false
}
},
考虑到JSON对象映射到Java POJO,JSON字符串映射到Java String
,JSON数组映射到Java数组或Collection
以及键映射到字段,让我们分析一下POJO类
public class AdsListResponse { // root is an object
@SerializedName("ads")
private List<Ad> mAds; // field of type List (Collection) mapping to the array
所以你已经映射
{ // an object at the root
"ads": [ // a key value pair, where the value is an array
{
下一个令牌是
"ad": { // a key value pair, where the value is an object
您没有POJO所在的位置。 您需要类似
public class AdWrapper {
@SerializedName("ad")
private Ad mAd;
然后将AdsListResponse
更改为
class AdsListResponse {
@SerializedName("ads")
private List<AdWrapper> mAds;
}
完成对象树。
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