我在我的Android应用程序中使用GSON。目前，我正在设置一个方法，其中包含来自我的JSON字符串中名为“follow”的值。 JSON字符串中的一个项包含follow，第二个字符串不包含。我使用Realm来保存唯一对象，以便您可以看到它被覆盖。
这里有2个json字符串作为例子进行比较：
{"customer_case":"OFFICE001","circle_id":"3","address":"10 Canal St","city":"Bristol","state":"PA","zip":"19007","county":"Bucks County","apt_no":"","latitude":"40.1012666","longitude":"-74.855304","profile_picture":"uploads/thumbnails/2014/06/07/16/1402165202_3_16_539356ad9134b3.jpg","id":"539356ad9134b3","google_address":"10 Canal Street","google_city":"Bristol","google_state":"Pennsylvania","verified_zip":"19007","google_county":"Bucks County","status":"Active","add_date":"2014-06-07","circle_name":"Test Portfolio","step":"Rental","loan":"","winterized":null,"boiler":null,"sump_pump":null,"septic":null,"police_id":null,"police":null,"police_phone":null,"electric_id":null,"electric":null,"electric_phone":null,"sewer_id":null,"sewer":null,"sewer_phone":null,"water_id":null,"water":null,"water_phone":null,"fsm_company_id":"5","fsm_company":"Assero Services LLC - FSM","fsm_email":"leemertins@assero24.com","fsm_phone":"2155868317","hoa_id":null,"hoa":null,"hoa_email":null,"hoa_phone":null,"client_id":"9","client":"Test Client","client_email":"krishna162@gmail.com","client_phone":"2157830782","broker_contact_id":null,"broker":null,"broker_email":null,"broker_phone":null,"lawn_contractor":null,"cleaning_contractor":null,"bedroom":null,"bathroom":null,"sqft":null,"lot_size":null,"list_price":"538525","built":null,"assign_date":"06/07/2014","lock_box":null,"gate_code":null,"key_code":null,"property_type":"Unknown","description":null,"sub_status":null,"occupancy_status":null,"street_view":"uploads/2015/06/25/4036/0470e4cd-ce9d-4439-8031-6be5101cd09c.JPG","marketing_front":"uploads/2015/06/25/4036/b099a190-f354-454a-8479-bec67bc41988.JPG","followed":"1"}
{"customer_case":"OFFICE001","circle_id":"3","address":"10 Canal St","city":"Bristol","state":"PA","zip":"19007","county":"Bucks County","apt_no":"","latitude":"40.1012666","longitude":"-74.855304","profile_picture":"uploads/thumbnails/2014/06/07/16/1402165202_3_16_539356ad9134b3.jpg","id":"539356ad9134b3","google_address":"10 Canal Street","google_city":"Bristol","google_state":"Pennsylvania","verified_zip":"19007","google_county":"Bucks County","status":"Active","add_date":"2014-06-07","circle_name":"Test Portfolio","step":"Rental","loan":"","winterized":null,"boiler":null,"sump_pump":null,"septic":null,"police_id":null,"police":null,"police_phone":null,"electric_id":null,"electric":null,"electric_phone":null,"sewer_id":null,"sewer":null,"sewer_phone":null,"water_id":null,"water":null,"water_phone":null,"fsm_company_id":"5","fsm_company":"Assero Services LLC - FSM","fsm_email":"leemertins@assero24.com","fsm_phone":"2155868317","hoa_id":null,"hoa":null,"hoa_email":null,"hoa_phone":null,"client_id":"9","client":"Test Client","client_email":"krishna162@gmail.com","client_phone":"2157830782","broker_contact_id":null,"broker":null,"broker_email":null,"broker_phone":null,"lawn_contractor":null,"cleaning_contractor":null,"bedroom":null,"bathroom":null,"sqft":null,"lot_size":null,"list_price":"538525","built":null,"assign_date":"06/07/2014","lock_box":null,"gate_code":null,"key_code":null,"property_type":"Unknown","description":null,"sub_status":null,"occupancy_status":null,"street_view":"uploads/2015/06/25/4036/0470e4cd-ce9d-4439-8031-6be5101cd09c.JPG","marketing_front":"uploads/2015/06/25/4036/b099a190-f354-454a-8479-bec67bc41988.JPG"}
请注意，区别在于json字符串末尾的后续项目。
从GSON文档中可以看出： “在反序列化时，JSON中缺少的条目导致将对象中的相应字段设置为null。”
有没有办法覆盖它并且不会自动将其设置为null，而只是跳过该字段？
以下是我用来反序列化json的一些代码：
PropertyObject prop = visnetawrap.gsonClient.fromJson(properties.get(i).toString(), PropertyObject.class);
visnetawrap.gsonClient = new GsonBuilder()
.setExclusionStrategies(new ExclusionStrategy() {
@Override
public boolean shouldSkipField(FieldAttributes f) {
return f.getDeclaringClass().equals(RealmObject.class) || f.getDeclaredClass().equals(Drawable.class);
}
@Override
public boolean shouldSkipClass(Class<?> clazz) {
return false;
}
})
.registerTypeAdapter(Date.class, new GsonDateDeserializer())
.registerTypeAdapter(Double.class, new TypeAdapter<Double>() {
@Override
public void write(JsonWriter out, Double value) throws IOException {
if (value == null) {
out.nullValue();
return;
}
out.value(value);
}
@Override
public Double read(JsonReader in) throws IOException {
if (in.peek() == JsonToken.NULL) {
in.nextNull();
return null;
}
String stringValue = in.nextString();
try {
return Double.valueOf(stringValue);
} catch (NumberFormatException e) {
return null;
}
}
})
.create();
答案 0 :(得分：1)
以下是我正在做的工作：
.registerTypeAdapter(PropertyObject.class, new JsonDeserializer<PropertyObject>() {
@Override
public PropertyObject deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
PropertyObject prop = new PropertyObject();
JsonObject propObj = json.getAsJsonObject();
if (propObj.get("id") == null) {
return null;
}
prop.setPropertyId(propObj.get("id").getAsString());
if (propObj.get("followed") == null) {
Realm realmThread = Realm.getDefaultInstance();
PropertyObject existingProp = realmThread.where(PropertyObject.class).equalTo("propertyId", propObj.get("id").getAsString()).findFirst();
if (existingProp == null) {
prop.setPropertyFollowed(0);
}
else {
prop.setPropertyFollowed(existingProp.getPropertyFollowed());
}
realmThread.close();
}
else {
prop.setPropertyFollowed(propObj.get("followed").getAsInt());
}
return prop;
}
})
答案 1 :(得分：0)
您可以创建自己的TypeAdapter
public class YourTypeAdapter extends TypeAdapter<PropertyObject> {
@Override
public PropertyObject read(final JsonReader in) throws IOException {
final PropertyObject obj = new PropertyObject(); //I don't know how is your obj
in.beginObject();
boolean hasFollowedField = false;
while (in.hasNext()) {
switch (in.nextName()) {
case "gate_code":
//set value to your obj
obj.setValue(in.nextString())
break;
//do same thing to others...
//...
case "followed":
hasFollowedField = true;
//set value to obj
break;
}
if (!hasFollowedField) {
//set followed value to obj what you want
}
}
in.endObject();
return obj;
}
@Override
public void write(final JsonWriter out, final PropertyObject obj) throws IOException {
out.beginObject();
out.name("gate_code").value(gate_code.getGateCode());
//simple set name and value from obj to JsonWriter
out.endObject();
}
}
然后将TypeAdapter注册到您的GsonBuilder对象
希望它会有所帮助