JodaTime LocalDate / LocalTime無法使用自定義JSON序列化器類進行解析

Question

我有稱為對象ReportEvent這需要在一個LocalTime ，以及一個LocalDate從JodaTime API /框架。 此ReportEvent可以通過Google的GSON轉換API寫入JSON 。 但是，在反序列化JodaTime partial會導致問題。

Logcat錯誤報告：

10-16 13:23:01.812: E/AndroidRuntime(8884): FATAL EXCEPTION: main
10-16 13:23:01.812: E/AndroidRuntime(8884): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nanospark.cnc/com.nanospark.cnc.MainActivity}: java.lang.IllegalArgumentException: Invalid format: "{"iChronology":{"iBase":{"iMinDa..."
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.os.Looper.loop(Looper.java:137)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread.main(ActivityThread.java:5103)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at java.lang.reflect.Method.invokeNative(Native Method)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at java.lang.reflect.Method.invoke(Method.java:525)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at dalvik.system.NativeStart.main(Native Method)
10-16 13:23:01.812: E/AndroidRuntime(8884): Caused by: java.lang.IllegalArgumentException: Invalid format: "{"iChronology":{"iBase":{"iMinDa..."
10-16 13:23:01.812: E/AndroidRuntime(8884):     at org.joda.time.format.DateTimeFormatter.parseLocalDateTime(DateTimeFormatter.java:854)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at org.joda.time.format.DateTimeFormatter.parseLocalDate(DateTimeFormatter.java:798)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.nanospark.cnc.LocalDateSerializer.deserialize(LocalDateSerializer.java:32)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.nanospark.cnc.LocalDateSerializer.deserialize(LocalDateSerializer.java:1)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:95)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:183)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:81)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.Gson.fromJson(Gson.java:805)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.Gson.fromJson(Gson.java:770)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.google.gson.Gson.fromJson(Gson.java:719)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.nanospark.cnc.GlobalData.retrieveGlobalDataFromStorage(GlobalData.java:118)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at com.nanospark.cnc.MainActivity.onCreate(MainActivity.java:35)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.Activity.performCreate(Activity.java:5133)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-16 13:23:01.812: E/AndroidRuntime(8884):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
10-16 13:23:01.812: E/AndroidRuntime(8884):     ... 11 more

代碼的相關部分：

LocalTime序列化器/反序列化器。

package com.nanospark.cnc;

import java.lang.reflect.Type;

import org.joda.time.LocalTime;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;


public class LocalTimeSerializer implements JsonDeserializer<LocalTime>, JsonSerializer<LocalTime>
{

   private static final DateTimeFormatter TIME_FORMAT = ISODateTimeFormat.timeNoMillis();

   @Override
   public LocalTime deserialize(final JsonElement je, final Type type,
                           final JsonDeserializationContext jdc) throws JsonParseException
   {
      final String dateAsString = je.toString();
      if (je.isJsonNull() || dateAsString.length() == 0)
      {
         return null;
      }
      else
      {
         return TIME_FORMAT.parseLocalTime(dateAsString);         
      }
   }

   @Override
   public JsonElement serialize(final LocalTime src, final Type typeOfSrc,
                                final JsonSerializationContext context)
   {
      String retVal;
      if (src == null)
      {
         retVal = "";
      }
      else
      {
         retVal = TIME_FORMAT.print(src);
      }
      return new JsonPrimitive(retVal);
   }

}

LocalDate序列化器/反序列化器。

public class LocalDateSerializer implements JsonSerializer<LocalDate>, JsonDeserializer<LocalDate>
{

  private static final String PATTERN = "yyyy-MM-dd";
  final DateTimeFormatter fmt = DateTimeFormat.forPattern(PATTERN);


  @Override
  public JsonElement serialize(LocalDate src, Type typeOfSrc, JsonSerializationContext context)
  {
    String retVal = fmt.print(src);
    Log.v("MY LOCALDATE SERIALIZED", retVal);
    return new JsonPrimitive(retVal);
  }


  @Override
  public LocalDate deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException
  {

    Log.v("MY LOCALDATE DESERIALIZED",json.toString());
    return fmt.parseLocalDate(json.toString());
  }
}

Answer 1

問題在於您擁有的序列化數據的代碼。

在您最初的問題中，當您要反序列化時有以下代碼（ retrieveGlobalDataFromStorage ）：

final GsonBuilder builder = new GsonBuilder()
   .registerTypeAdapter(LocalDate.class, new LocalDateSerializer())
   .registerTypeAdapter(LocalTime.class, new LocalTimeSerializer());
final Gson gson = builder.create();  

但是，當您要序列化 （ storeGlobalData ）時，您只有：

Gson gson = new Gson();

您應該在兩個地方都注冊類型適配器。 我將代碼（ Gson初始化）提取到一個單獨的方法中，您可以從這兩個方法中調用該方法。

Answer 2

在使用deserialize()時也要小心

    return fmt.parseLocalDate(json.toString());

因為它會產生可能的意外引號""2014-10-28"" 。

最好改用：

    return fmt.parseLocalDate(json.getAsString());