我有问题，App Engine返回Long / long值作为“字符串”。这是返回的JSON文件的一部分：
"stringObject" : "This is a string.",
"integerPrimitive" : -3,
"intergerObject" : 3333,
"longPrimitive" : "1234567890123456789",
"longObject" : "1234567890123456789",
以及产生它的服务器端数据类型：
private String stringObject = "This is a string.";
private int integerPrimitive = -3;
private Integer intergerObject = 3333;
private long longPrimitive = 1234567890123456789L;
private Long longObject = 1234567890123456789L;
我已经编写了TypeAdapter来处理Long，但似乎在反序列化期间GSON不会查看目标变量，而是查看JSON本身。换句话说：似乎仍然为Long / long调用String TypeAdapter，至少从未达到我的TypeAdapter中的断点（不过，这也可能是反射的产物）。这是可能的还是我的TypeAdapter另一个问题？ GSON如何确定它调用哪个适配器。
public class LongTypeAdapter extends TypeAdapter<Long> {
// Long/long is converted to String by AppEngine 0L -> "0"
@Override public void write(JsonWriter writer, Long value) throws IOException {
if (value == null) {
writer.nullValue();
return;
}
String text = "\"" + String.valueOf(value) + "\"";
writer.value(text);
}
@Override public Long read(JsonReader reader) throws IOException {
if (reader.peek() == JsonToken.NULL) {
reader.nextNull();
return null;
}
String text = reader.nextString();
text = text.replaceAll("\"", "");
Long value = Long.parseLong(text);
return value;
}
}
我调试到GSON并正确注册了适配器，因此很可能会在这里排除注册问题。
这是注册适配器的方式：
public class Backend {
// Singleton
private static volatile BackendInterface service = null;
private Backend() {} // exists only to defeat instantiation
public static BackendInterface api() {
if (service == null) { // lazy initialization
final Gson gson = new GsonBuilder()
.registerTypeAdapter(Long.class, new LongTypeAdapter())
.create();
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint(Constants.BACKEND_API_ENDPOINT)
.setClient(new OkClient())
.setLogLevel(RestAdapter.LogLevel.FULL) // TODO remove full logging for production
.setConverter(new GsonConverter(gson))
.build();
service = restAdapter.create(BackendInterface.class);
}
return service;
}
}
这是我的用法：
Test test = Backend.api().getTest(2L);
最佳答案
好了，您必须注册新型适配器：
final Gson gson = new GsonBuilder().registerTypeAdapter(Long.class,
new LongTypeAdapter()).create();
希望对您有所帮助