[안드로이드] 서버에 데이터 요청 및 응답 (소켓 통신)

 

 

클라이언트와 서버 소켓을 생성

클라이언트 -> 서버 (데이터 요청)

서버 -> 클라이언트 (데이터 응답)

 

 

 

 

 

 

[activity_main.xml]

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#4aa8d8"
        android:orientation="vertical">

        <EditText
            android:id="@+id/editText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:hint=""
            android:inputType="textPersonName"
            tools:ignore="SpeakableTextPresentCheck" />

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="전송" />

        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical" >

                <TextView
                    android:id="@+id/textView"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:textSize="20sp" />
            </LinearLayout>
        </ScrollView>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#ff7f00"
        android:orientation="vertical">

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="서버 시작" />

        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/textView2"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:textSize="20sp"
                    />
            </LinearLayout>
        </ScrollView>
    </LinearLayout>
</LinearLayout>

 

 

[MainActivity.java]

package org.techtown.samplesocket;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class MainActivity extends AppCompatActivity {

    EditText editText;
    TextView textView, textView2;
    Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText = findViewById(R.id.editText);
        textView = findViewById(R.id.textView);
        textView2 = findViewById(R.id.textView2);

        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final String data = editText.getText().toString();
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        send(data);
                    }
                }).start();
            }
        });

        Button button2 = findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        startServer();
                    }
                }).start();
            }
        });
    }

    public void printClientLog(final String data) {
        Log.d("MainActivity", data);

        handler.post(new Runnable() {
            @Override
            public void run() {
                textView.append(data + "\n");
            }
        });
    }

    public void printServerLog(final String data) {
        Log.d("MainActivity", data);

        handler.post(new Runnable() {
            @Override
            public void run() {
                textView2.append(data + "\n");
            }
        });
    }

    public void send(String data) {
        try {
            int portNumber = 5001;
            Socket sock = new Socket("localhost", portNumber);
            printClientLog("소켓 연결함");

            ObjectOutputStream outStream = new ObjectOutputStream(sock.getOutputStream());
            outStream.writeObject(data);
            outStream.flush();
            printClientLog("데이터 전송함");

            ObjectInputStream insTream = new ObjectInputStream(sock.getInputStream());
            printClientLog("서버로부터 받음 : " + insTream.readObject());
            sock.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public void startServer() {
        try {
            int portNumber = 5001;

            ServerSocket server = new ServerSocket(portNumber);
            printServerLog("서버 시작함: " + portNumber);

            while (true) { // 클라이언트 접속 대기
                Socket sock = server.accept(); //접속 요청 오면 accept 메서드를 통해 소켓 객체 반환
                InetAddress clientHost = sock.getLocalAddress(); // 클라이언트 연결 정보 확인 가능
                int clientPort = sock.getPort(); // 클라이언트 포트 번호 확인
                printServerLog("클라이언트 연결됨: " + clientHost + " : " + clientPort);

                ObjectInputStream instream = new ObjectInputStream(sock.getInputStream());
                Object obj = instream.readObject(); // 문자열 받아와
                printServerLog("데이터 받음: " + obj); //

                ObjectOutputStream outstream = new ObjectOutputStream(sock.getOutputStream());
                outstream.writeObject(obj + " from Server."); //from server 라는 문자열 붙여서 클라이언트로 다시 보내
                outstream.flush();
                printServerLog("데이터 보냄.");

                sock.close();
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

 

 

 

 

참고 : Do it! 안드로이드 앱 프로그래밍