diff --git a/DataFormat.java b/DataFormat.java
index 85c2121..4886c4a 100644
--- a/DataFormat.java
+++ b/DataFormat.java
@@ -1,4 +1,19 @@
-class LoginData
+import com.google.gson.Gson;
+
+class AppJsonData
+{
+	private String type;
+	public String getType()
+	{
+		return type;
+	}
+	public void setType(String Type)
+	{
+		type=Type;
+	}
+}
+
+class LoginData extends AppJsonData
 {
 	private String email;
 	private String pwass;
@@ -43,7 +58,7 @@ class RegisterData extends LoginData
 	}
 }
 
-class UploadData
+class UploadData extends AppJsonData
 {
 	private String bookname;
 	private String author;
@@ -97,3 +112,17 @@ class FetchData extends UploadData
 		label=Label;
 	}
 }
+
+
+/*
+public class JsonStudy
+{
+	public static void main(String[] args)
+	{
+		String jsonData="{'type':'register','email':'test@163.com','nickname':'Kirito','school':'QUST','pwass':'dvaLovesU'}";
+		Gson gson=new Gson();
+		RegisterData data=gson.fromJson(jsonData, RegisterData.class);
+		System.out.println("Email:"+data.getEmail()+" NickName:"+data.getNickname()+" School:"+data.getSchool()+" Password:"+data.getPass());
+	}
+}
+*/
\ No newline at end of file