Java 从未调用日期的自定义gson反序列化程序

据我所知，gson不会自动将java.util.Date对象序列化和反序列化为ISO字符串，例如“yyyy-MM-ddTHH:MM:ssZ”或“2014-04-15T18:22:00-05:00”。因此，为了使我能够在我的客户机（使用gson改造）和服务器之间正确地通信日期，我需要为gson指定日期格式。以下是我所做的：

// code defining the creation of a RestAdapter
// ...
new GsonBuilder()
    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
    .create()

添加.setDateFormat行足以让gson将时间戳字符串正确地反序列化到日期对象中。但是，它没有将日期对象序列化为时间戳字符串。因此，我假设必须创建一个自定义序列化程序，如下所示：

// code defining the creation of a RestAdapter
// ...
new GsonBuilder()
    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
    .registerTypeAdapter(Date.class, new DateSerializer())
    .create()

和DateSerializer类：

class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
        return new JsonPrimitive(df.format(arg0));
    }
}

但当然，永远不会抛出RuntimeException

有人知道为什么我的序列化函数被忽略了吗？我想我在某个地方读到，对于某些类型，如果为超类定义了一个registerTypeAdapter，那么它将被忽略，但是由于这是java.util.Date，如果这是问题所在，我会感到困惑。我可能只是在做一些愚蠢的事情，但我可能对Date或gson不太了解，无法意识到这一点

编辑：提供了有关以下代码的更多上下文：

MyApplication.java

public class MyApplication extends Application {
    public static RestAdapter restAdapter;
    public static The1Api the1Api;

    public static void createRestAdapter(String server_url){
        // enable cookies
        CookieManager cookieManager = new CookieManager();
        cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
        CookieHandler.setDefault(cookieManager);

        // create rest adapter
        restAdapter = new RestAdapter.Builder()
            .setEndpoint(server_url)
            .setConverter(new GsonConverter(new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
                    .registerTypeAdapter(Date.class, new DateSerializer())
                    .create()))
            .setLogLevel(LogLevel.FULL)
            .setLog(new ResponseInterceptor())
            .build();

        // create API
        the1Api = restAdapter.create(The1Api.class);
    }
}

public interface The1Api {
    /* Chat */

    public class PublicMessage {
        String from_user;
        String message;
        Date time;
        Integer microsecond;
        Boolean in_1_percent;
    }
    public class PublicMessageList {
        Integer last_message_id;
        ArrayList<PublicMessage> messages;
    }

    @GET("/chat/get_public_messages/")
    public PublicMessageList getPublicMessages(
            @Query("last_message_id") Integer last_message_id, // optional
            @Query("since") Date since, // optional
            @Query("max") Integer max // optional
            );   

    // ...
}

public class LoginActivity extends Activity {
    // ...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Crashlytics.start(this);
        MyApplication.createRestAdapter(getString(R.string.server_url));
        setContentView(R.layout.activity_login);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState){
        super.onPostCreate(savedInstanceState);

        Thread thread = new Thread(){
            @Override
            public void run(){
                ArrayList<The1Api.PublicMessage> publicMessages = MyApplication.the1Api.getPublicMessages(null, null, null).messages;
                for (The1Api.PublicMessage m : publicMessages){
                    Log.d("The1", "[" + m.time.toString() + "] " + m.from_user + ": " + m.message);
                }
                // when the following line gets executed, my server receives a request including the date below,
                // but the server does not understand the format of the date because it does not get serialized properly
                MyApplication.the1Api.getPublicMessages(null, new Date(1000000000), null);
            }
        };
        thread.start();
    }

    // ...    
}

class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
        return new JsonPrimitive(df.format(arg0));
    }
}

1api.java

public class MyApplication extends Application {
    public static RestAdapter restAdapter;
    public static The1Api the1Api;

    public static void createRestAdapter(String server_url){
        // enable cookies
        CookieManager cookieManager = new CookieManager();
        cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
        CookieHandler.setDefault(cookieManager);

        // create rest adapter
        restAdapter = new RestAdapter.Builder()
            .setEndpoint(server_url)
            .setConverter(new GsonConverter(new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
                    .registerTypeAdapter(Date.class, new DateSerializer())
                    .create()))
            .setLogLevel(LogLevel.FULL)
            .setLog(new ResponseInterceptor())
            .build();

        // create API
        the1Api = restAdapter.create(The1Api.class);
    }
}

public interface The1Api {
    /* Chat */

    public class PublicMessage {
        String from_user;
        String message;
        Date time;
        Integer microsecond;
        Boolean in_1_percent;
    }
    public class PublicMessageList {
        Integer last_message_id;
        ArrayList<PublicMessage> messages;
    }

    @GET("/chat/get_public_messages/")
    public PublicMessageList getPublicMessages(
            @Query("last_message_id") Integer last_message_id, // optional
            @Query("since") Date since, // optional
            @Query("max") Integer max // optional
            );   

    // ...
}

public class LoginActivity extends Activity {
    // ...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Crashlytics.start(this);
        MyApplication.createRestAdapter(getString(R.string.server_url));
        setContentView(R.layout.activity_login);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState){
        super.onPostCreate(savedInstanceState);

        Thread thread = new Thread(){
            @Override
            public void run(){
                ArrayList<The1Api.PublicMessage> publicMessages = MyApplication.the1Api.getPublicMessages(null, null, null).messages;
                for (The1Api.PublicMessage m : publicMessages){
                    Log.d("The1", "[" + m.time.toString() + "] " + m.from_user + ": " + m.message);
                }
                // when the following line gets executed, my server receives a request including the date below,
                // but the server does not understand the format of the date because it does not get serialized properly
                MyApplication.the1Api.getPublicMessages(null, new Date(1000000000), null);
            }
        };
        thread.start();
    }

    // ...    
}

class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
        return new JsonPrimitive(df.format(arg0));
    }
}

公共接口API{
/*聊天*/
公共类公共消息{
来自用户的字符串；
字符串消息；
日期时间；
整数微秒；
布尔值，单位为1%；
}
公共类PublicMessageList{
整数last_message_id；
ArrayList消息；
}
@获取（“/chat/GET\u public\u messages/”）
PublicMessageList getPublicMessages(
@查询（“last\u message\u id”）整数last\u message\u id，//可选
@查询（“自”）日期自，//可选
@查询（“max”）整数max//可选
);   
// ...
}

LoginActivity.java

public class MyApplication extends Application {
    public static RestAdapter restAdapter;
    public static The1Api the1Api;

    public static void createRestAdapter(String server_url){
        // enable cookies
        CookieManager cookieManager = new CookieManager();
        cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
        CookieHandler.setDefault(cookieManager);

        // create rest adapter
        restAdapter = new RestAdapter.Builder()
            .setEndpoint(server_url)
            .setConverter(new GsonConverter(new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
                    .registerTypeAdapter(Date.class, new DateSerializer())
                    .create()))
            .setLogLevel(LogLevel.FULL)
            .setLog(new ResponseInterceptor())
            .build();

        // create API
        the1Api = restAdapter.create(The1Api.class);
    }
}

public interface The1Api {
    /* Chat */

    public class PublicMessage {
        String from_user;
        String message;
        Date time;
        Integer microsecond;
        Boolean in_1_percent;
    }
    public class PublicMessageList {
        Integer last_message_id;
        ArrayList<PublicMessage> messages;
    }

    @GET("/chat/get_public_messages/")
    public PublicMessageList getPublicMessages(
            @Query("last_message_id") Integer last_message_id, // optional
            @Query("since") Date since, // optional
            @Query("max") Integer max // optional
            );   

    // ...
}

public class LoginActivity extends Activity {
    // ...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Crashlytics.start(this);
        MyApplication.createRestAdapter(getString(R.string.server_url));
        setContentView(R.layout.activity_login);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState){
        super.onPostCreate(savedInstanceState);

        Thread thread = new Thread(){
            @Override
            public void run(){
                ArrayList<The1Api.PublicMessage> publicMessages = MyApplication.the1Api.getPublicMessages(null, null, null).messages;
                for (The1Api.PublicMessage m : publicMessages){
                    Log.d("The1", "[" + m.time.toString() + "] " + m.from_user + ": " + m.message);
                }
                // when the following line gets executed, my server receives a request including the date below,
                // but the server does not understand the format of the date because it does not get serialized properly
                MyApplication.the1Api.getPublicMessages(null, new Date(1000000000), null);
            }
        };
        thread.start();
    }

    // ...    
}

class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
        return new JsonPrimitive(df.format(arg0));
    }
}

公共类LoginActivity扩展活动{
// ...
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
Crashlytics.启动（此）；
createRestAdapter（getString（R.string.server_url））；
setContentView（R.layout.activity\u登录）；
}
@凌驾
后期创建时受保护的空（捆绑包savedInstanceState）{
super.onPostCreate（savedInstanceState）；
线程线程=新线程（）{
@凌驾
公开募捐{
ArrayList publicMessages=MyApplication.1API.getPublicMessages（null，null，null）.messages；
for（1api.PublicMessage m:publicMessages）{
Log.d（“The1”，“[”+m.time.toString（）+“]”“+m.from_user+”：“+m.message”）；
}
//当执行以下行时，我的服务器收到一个包含以下日期的请求，
//但是服务器不理解日期的格式，因为它没有正确序列化
MyApplication.1API.getPublicMessages（null，新日期（100000000），null）；
}
};
thread.start（）；
}
// ...    
}

DateSerializer.java

public class MyApplication extends Application {
    public static RestAdapter restAdapter;
    public static The1Api the1Api;

    public static void createRestAdapter(String server_url){
        // enable cookies
        CookieManager cookieManager = new CookieManager();
        cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
        CookieHandler.setDefault(cookieManager);

        // create rest adapter
        restAdapter = new RestAdapter.Builder()
            .setEndpoint(server_url)
            .setConverter(new GsonConverter(new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
                    .registerTypeAdapter(Date.class, new DateSerializer())
                    .create()))
            .setLogLevel(LogLevel.FULL)
            .setLog(new ResponseInterceptor())
            .build();

        // create API
        the1Api = restAdapter.create(The1Api.class);
    }
}

public interface The1Api {
    /* Chat */

    public class PublicMessage {
        String from_user;
        String message;
        Date time;
        Integer microsecond;
        Boolean in_1_percent;
    }
    public class PublicMessageList {
        Integer last_message_id;
        ArrayList<PublicMessage> messages;
    }

    @GET("/chat/get_public_messages/")
    public PublicMessageList getPublicMessages(
            @Query("last_message_id") Integer last_message_id, // optional
            @Query("since") Date since, // optional
            @Query("max") Integer max // optional
            );   

    // ...
}

public class LoginActivity extends Activity {
    // ...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Crashlytics.start(this);
        MyApplication.createRestAdapter(getString(R.string.server_url));
        setContentView(R.layout.activity_login);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState){
        super.onPostCreate(savedInstanceState);

        Thread thread = new Thread(){
            @Override
            public void run(){
                ArrayList<The1Api.PublicMessage> publicMessages = MyApplication.the1Api.getPublicMessages(null, null, null).messages;
                for (The1Api.PublicMessage m : publicMessages){
                    Log.d("The1", "[" + m.time.toString() + "] " + m.from_user + ": " + m.message);
                }
                // when the following line gets executed, my server receives a request including the date below,
                // but the server does not understand the format of the date because it does not get serialized properly
                MyApplication.the1Api.getPublicMessages(null, new Date(1000000000), null);
            }
        };
        thread.start();
    }

    // ...    
}

class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
        return new JsonPrimitive(df.format(arg0));
    }
}

类DateSerializer实现JsonSerializer{ @凌驾 公共JsonElement序列化（日期arg0，类型arg1，JsonSerializationContext arg2）{ SimpleDataFormat df=新的SimpleDataFormat（“yyyy-MM-dd'T'HH:MM:ssZ”，Locale.US）； 返回新的JsonPrimitive（df.format（arg0））； } }

---

编辑2：目前还没有解决方案，但作为一种解决方法，您可以在发送日期之前手动将日期转换为其他格式。在Kalle建议将其转换为字符串的注释中，我将其转换为Long（自UNIX时代以来的秒数）。

您仍然能够复制此问题吗？我看到Gson正确地序列化和反序列化了。这可能是一个改装问题（我以前没有使用过），但查看文档，除了委托给

Gson

中提供的对象之外，我看不出有任何其他原因

这是一个SSCCE：

public class GsonDateDemo {
  public static void main(String[] args) {
    Gson gson = new GsonBuilder()
        .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
        .registerTypeAdapter(Date.class, new DateSerializer())
        .create();
    Date d = new Date(1438806977000L);

    System.out.println("Serializing "+d);
    String json = gson.toJson(d);
    System.out.println("JSON: "+json);
    Date d2 = gson.fromJson(json, Date.class);
    System.out.println("Deserialized: "+d2);
    System.out.println("Equal? "+d.equals(d2));
  }

  static class DateSerializer implements JsonSerializer<Date> {
    @Override
    public JsonElement serialize(Date arg0, Type arg1, JsonSerializationContext arg2) {
      System.out.println("Serializer received "+arg0);
      SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US);
      return new JsonPrimitive(df.format(arg0));
    }
  }
}

---

如果可以，请修改此SSCCE以使用改型，并查看是否可以通过这种方式复制故障。

gson中的问题，当我们尝试使用after call

setDateFormat

反序列化时，自定义

DateDesializer

不调用

---

因此，在反序列化时，不要调用

setDateFormat

；）

首先看一下

SimpleDateFormat df=newsimpledateformat（“yyyy-MM-dd'T'HH:MM:ssZ”，Locale.US）和
df.format（arg0）
。如果它工作正常，则转到下一步定义自定义序列化程序。要了解更多信息，请查看我之前尝试调试这些行时，我注意到它们从未被调用-因此我尝试用抛出RuntimeException替换代码。然而，由于序列化程序从未被调用，即使这些行是错误的，也不会是问题，是吗？所以问题是序列化程序从未被调用。如果我错了，请纠正我。你能发布你的完整代码吗。您使用的是什么JSON？返回的Gson是如何使用的？谢谢Kalle，应该有用！在与该项目的其他一位工程师讨论之后，我们决定将日期时间传递为long（自UNIX纪元以来的秒数），这似乎对我们有用。因为这只是一个解决办法，但我会留下问题，以防翻新/Gson得到更新（我不知道谁该负责）；恐怕我不能试一试。如果我再次遇到类似的问题，我会回到这个问题上来。也许其他经历过这个问题的人能够分享他们的想法？