I want to send 2 objects to Java server from Android client using socket (as I am developing a Remote PC).
AndroidClient.java
public class MainActivity extends Activity{
Socket client;
ObjectOutputStream oos;
OutputStream os;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SendObj so=new SendObj();
so.execute();
}
class SendObj extends AsyncTask<Void, Void, Void>{
@Override
protected Void doInBackground(Void... arg0) {
try {
client=new Socket("192.168.237.1",6566);
os=client.getOutputStream();
oos=new ObjectOutputStream(os);
Serializer ma=new Serializer(2, "Helllo");
Log.i("Serial",""+ma.name);
oos.writeObject(ma);
oos.writeObject(new String("Another Object from Client"));
oos.close();
os.close();
client.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
@SuppressWarnings("serial")
class Serializer implements Serializable {
int num;
String name;
public Serializer(int num,String name){
this.name=name;
this.num=num;
}
}
JavaServer.java
public class ObjectReceiver {
static ServerSocket server;
static Socket client;
static ObjectInputStream ois;
static InputStream is;
public static void main(String[] arg) throws IOException, ClassNotFoundException{
server=new ServerSocket(6566);
System.out.println("Wait");
while(true){
client=server.accept();
System.out.println("Connected");
is=client.getInputStream();
ois=new ObjectInputStream(is);
try {
ObjectSerail or = (ObjectSerail) ois.readObject();
if(or!=null){
System.out.println("Done");
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
@SuppressWarnings("serial")
class ObjectSerail implements Serializable{
int num;
String name;
public ObjectSerail(int num,String name){
this.name=name;
this.num=num;
}
}
}
Of course I know the above method won't work because it will gives ClassNotFoundException()
. So now I want to know how can I use Gson library to serialize and deserialize the objects. Thanks in advance.
Serialization in the context of Gson means converting a Java object to its JSON representation. In order to do the serialization, we need to create the Gson object, which handles the conversion. Next, we need to call the function toJson() and pass the User object. Program output.
Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.
Gson is the main actor class of Google Gson library. It provides functionalities to convert Java objects to matching JSON constructs and vice versa. Gson is first constructed using GsonBuilder and then toJson(Object) or fromJson(String, Class) methods are used to read/write JSON constructs.
If you're concerned about parsing speed for your JSON library, choose Jackson for big files, GSON for small files, and JSON. simple for handling both.
gson can be used with Java on any platform – not only Android.
Using gson to serialize a single object:
// Serialize a single object.
public String serializeToJson(MyClass myClass) {
Gson gson = new Gson();
String j = gson.toJson(myClass);
return j;
}
Using gson to deserialize to a single object.
// Deserialize to single object.
public MyClass deserializeFromJson(String jsonString) {
Gson gson = new Gson();
MyClass myClass = gson.fromJson(jsonString, MyClass.class);
return myClass;
}
As you can see from the examples, gson is quite magical :) It is not actually magical - you need to ensure at least a couple of things:
Ensure that your class has a no args constructor so that the gson library can easily get an instance.
Ensure that the attribute names match those in the json so that the gson library can map fields from the json to the fields in your class.
Also see https://sites.google.com/site/gson/gson-user-guide#TOC-Object-Examples
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