Java Firebase，类映射器：未找到'；用户二'；在课堂上'；myclass'；

所以firebase一直给我nullpointer异常，而且它在类“ChatModel”上找不到任何setter/字段，下面是我的ChatModel类：

package edusolution.matrimony;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by el on 8/26/16.
 */
public class ChatModel
{
    public Map<String,Object> message = new HashMap<>();
    public String foruser;
    public String foruserAnother;

    public  ChatModel()
    {

    }

    public  ChatModel(String foruser,String foruserAnother)
    {
        this.foruser = foruser;
        this.foruserAnother = foruserAnother;
    }

    public String getForuser()
    {
        return foruser;
    }

    public void setForuser(String foruser)
    {
        this.foruser = foruser;
    }

    public String getForuserAnother()
    {
        return foruserAnother;
    }

    public void setForuserAnother(String foruserAnother)
    {
        this.foruserAnother = foruserAnother;
    }

    public Map<String, Object> getMessage()
    {
        return message;
    }

    public void setMessage(Map<String,Object> message)
    {
        this.message = message;
    }

    public Map<String,Object> toMap()
    {
        HashMap<String,Object> result = new HashMap<>();
        message.put("somebody","iusedtoknow");
        result.put("UserOne",foruser);
        result.put("UserTwo",foruserAnother);
        result.put("Messages",message);
        return result;
    }
}

示例数据，保存在firebasedatabase中，图片：

最后，我每次都会收到：

08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for UserTwo found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for Messages found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for UserOne found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony D/Key and hash :: -KQGYLHb2IQ34AHkzx5G null
08-28 18:28:51.005 31762-31762/edusolution.matrimony D/AndroidRuntime: Shutting down VM
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41919700)
08-28 18:28:51.012 31762-31762/edusolution.matrimony E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerExceptio
    at edusolution.matrimony.Chat$1.onDataChange(Chat.java:70)
    at com.google.android.gms.internal.zzaie.zza(Unknown Source)
    at com.google.android.gms.internal.zzaje.zzcta(Unknown Source)
    at com.google.android.gms.internal.zzajh$1.run(Unknown Source)
    at android.os.Handler.handleCallback(Handler.java:730)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:5103)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:525)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    at dalvik.system.NativeStart.main(Native Method)

---

POJO类与数据库的结构不同

将您的

ChatModel

类字段更改为

public class ChatModel {
    public Map<String,Object> Messages = new HashMap<>();
    public String UserOne;
    public String UserTwo;

    // constructor
    // setter and getter
}

公共类聊天模型{
publicmap Messages=newhashmap（）；
公共字符串UserOne；
公共字符串user2；
//建造师
//接二连三
}

Ty，你是上帝派来的

08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for UserTwo found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for Messages found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/ClassMapper: No setter/field for UserOne found on class edusolution.matrimony.ChatModel
08-28 18:28:51.005 31762-31762/edusolution.matrimony D/Key and hash :: -KQGYLHb2IQ34AHkzx5G null
08-28 18:28:51.005 31762-31762/edusolution.matrimony D/AndroidRuntime: Shutting down VM
08-28 18:28:51.005 31762-31762/edusolution.matrimony W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41919700)
08-28 18:28:51.012 31762-31762/edusolution.matrimony E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerExceptio
    at edusolution.matrimony.Chat$1.onDataChange(Chat.java:70)
    at com.google.android.gms.internal.zzaie.zza(Unknown Source)
    at com.google.android.gms.internal.zzaje.zzcta(Unknown Source)
    at com.google.android.gms.internal.zzajh$1.run(Unknown Source)
    at android.os.Handler.handleCallback(Handler.java:730)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:5103)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:525)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    at dalvik.system.NativeStart.main(Native Method)

public class ChatModel {
    public Map<String,Object> Messages = new HashMap<>();
    public String UserOne;
    public String UserTwo;

    // constructor
    // setter and getter
}