[英]gson fails in deserializing simple interface
我有一個非常簡單的Java接口:
public interface GeographicalArea {
java.lang.String getTown();
java.lang.String getProvince();
java.lang.String getStreet();
java.lang.String getStreetNumber();
float getLongitude();
float getLatitude();
java.lang.String getPhoneNumber();
void setTown(java.lang.String s);
void setProvince(java.lang.String s);
void setStreet(java.lang.String s);
void setStreetNumber(java.lang.String s);
void setLongitude(float v);
void setLatitude(float v);
void setPhoneNumber(java.lang.String s);
}
具有相應的簡單實現:
public class GeographicalAreaImpl implements GeographicalArea {
private java.lang.String town;
private java.lang.String province;
private java.lang.String street;
private java.lang.String streetNumber;
private float longitude;
private float latitude;
private java.lang.String phoneNumber;
public GeographicalAreaImpl() { ... [compiled code]
public java.lang.String getTown() { ... [compiled code]
... all the other getters and setters declared in the Interface
我沒有它們的源代碼:我將它們放在需要使用的Jar中。
為了反序列化我收到的Java接口,我構建了一個InstanceCreator
:
public class InstanceCreatorGeographicalArea implements
InstanceCreator<GeographicalArea> {
@Override
public GeographicalArea createInstance(Type type) {
return new GeographicalAreaImpl();
}
}
並注冊到:
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(GeographicalArea.class, new InstanceCreatorGeographicalArea());
...
Gson gson = builder.create();
但是,gson無法反序列化我收到的數據:它沒有給出錯誤,但是所有字段均保留為空/空。
我不是Gson的專家,但是從閱讀的文檔中我已經做了我應該做的事情。
我做錯了什么?
您是否已閱讀以下內容:1) http://www.javacodegeeks.com/2012/04/json-with-gson-and-abstract-classes.html 2) Gson使用InstanceCreator反序列化嵌套對象 ?
顯然,該錯誤可能在以下行中:
builder.registerTypeAdapter(GeographicalAreaImpl.class,新......
使用實現而不是接口,並在InstanceCreatorGeographicalArea中使用此方法:public GeographicalAreaImpl createInstance(Type arg0){return new GeographicalAreaImpl(); }
測試班
public static void main(String[] args) {
GeographicalArea ga = new GeographicalAreaImpl();
ga.setLatitude(25);
ga.setLongitude(2);
ga.setPhoneNumber("2344");
ga.setProvince("xxx");
ga.setStreet("yyyyy");
ga.setStreetNumber("2");
ga.setTown("zzzzzzz");
Gson gson = new Gson();
String userJson = gson.toJson(ga);
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(GeographicalAreaImpl.class, new InstanceCreatorGeographicalArea());
Gson parser = builder.create();
GeographicalArea request = parser.fromJson(userJson, GeographicalAreaImpl.class);
System.out.println("Latitude " + request.getLatitude());
}
輸出:
Latitude 25.0
InstanceCreatorGeographicalArea類:
public class InstanceCreatorGeographicalArea implements InstanceCreator<GeographicalAreaImpl> {
@Override
public GeographicalAreaImpl createInstance(Type arg0) {
return new GeographicalAreaImpl();
}
}
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