Android中socket通信簡單實現

Android中socket通信簡單實現

socket通信需要有一個服務器和客戶端，可以把同一個APP作爲服務器跟客戶端，也可以分開成兩個APP。
先上個圖：

這裏以一個APP作爲服務器跟客戶端爲示例
1、添加網絡訪問權限

<uses-permission android:name="android.permission.INTERNET" />

2、寫服務器，在APP上啓動

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    ServerSocket serverSocket = null;
    public final int port = 9998;
    private int i = 0;

    public Server(){

        //輸出服務器的IP地址
        try {
            InetAddress addr = InetAddress.getLocalHost();
            System.out.println("local host:"+addr);
            serverSocket = new ServerSocket(port);
            System.out.println("0k");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void startService(){

        try {
            Socket socket = null;
            System.out.println("waiting...");
            //等待連接，每建立一個連接，就新建一個線程
            while(true){
                socket = serverSocket.accept();//等待一個客戶端的連接，在連接之前，此方法是阻塞的
                System.out.println("connect to"+socket.getInetAddress()+":"+socket.getLocalPort());
                new ConnectThread(socket).start();
            }

        } catch (IOException e) {
            // TODO Auto-generated catch block
            System.out.println("IOException");
            e.printStackTrace();
        }
    }

    //向客戶端發送信息
    class ConnectThread extends Thread{
        Socket socket = null;

        public ConnectThread(Socket socket){
            super();
            this.socket = socket;
        }

        @Override
        public void run(){
            try {
                DataInputStream dis = new DataInputStream(socket.getInputStream());
                DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
                while(true){
                    i++;
                    String msgRecv = dis.readUTF();
                    System.out.println("msg from client:"+msgRecv);
                    dos.writeUTF(msgRecv + i);
                    dos.flush();
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

需要在線程中調用，調用方法：

new Thread(() -> new Server().startService()).start();

3、客戶端代碼

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import androidx.appcompat.app.AppCompatActivity;

/**
 * @author fenghaitao
 * @time  2020年4月2日14:34:33
 * scoket客戶端連接測試
 */
public class SocketActivity extends AppCompatActivity {
    //IP地址和端口號
    public static String IP_ADDRESS = "";
    public static int PORT = 9998;
    //三個控件
    EditText et_message = null;  //需要發送的內容
    Button bt_getAdress = null;   //獲取本機IP地址
    Button bt_connect = null;   //連接併發送
    Button bt_startServer = null;   //啓動服務端
    TextView tv_adress = null;   //ip地址
    TextView tv_reply = null;   //服務器回覆的消息
    //handler
    Handler handler = null;
    Socket soc = null;
    DataOutputStream dos = null;
    DataInputStream dis = null;
    String messageRecv = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_socket);
        et_message = findViewById(R.id.et_message);
        bt_getAdress = findViewById(R.id.bt_getAdress);
        bt_connect = findViewById(R.id.bt_connect);
        bt_startServer = findViewById(R.id.bt_startServer);

        tv_adress = findViewById(R.id.tv_adress);
        tv_reply = findViewById(R.id.tv_reply);
        bt_getAdress.setOnClickListener(v -> {
            new Thread(() -> {
                try {
                    InetAddress addr = InetAddress.getLocalHost();
                    System.out.println("local host:"+addr);
                    runOnUiThread(() -> tv_adress.setText(addr.toString().split("/")[1]));
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                }
            }).start();
        });

        bt_startServer.setOnClickListener(v -> {
            new Thread(() -> new Server().startService()).start();
            Toast.makeText(SocketActivity.this,"服務已啓動",Toast.LENGTH_SHORT).show();
        });
        bt_connect.setOnClickListener(v -> {
            IP_ADDRESS = tv_adress.getText().toString();
            new ConnectionThread(et_message.getText().toString()).start();
        });
        handler = new Handler(msg -> {
            Bundle b = msg.getData();  //獲取消息中的Bundle對象
            String str = b.getString("data");  //獲取鍵爲data的字符串的值
            tv_reply.append(str);
            return false;
        });
    }

    //新建一個子線程，實現socket通信
    class ConnectionThread extends Thread {
        String message = null;

        public ConnectionThread(String msg) {
            message = msg;
        }

        @Override
        public void run() {
            if (soc == null) {
                try {
                    //Log.d("socket","new socket");
                    if ("".equals(IP_ADDRESS)) {
                        return;
                    }
                    soc = new Socket(IP_ADDRESS, PORT);
                    //獲取socket的輸入輸出流
                    dis = new DataInputStream(soc.getInputStream());
                    dos = new DataOutputStream(soc.getOutputStream());
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            try {
                dos.writeUTF(message);
                dos.flush();
                messageRecv = dis.readUTF();//如果沒有收到數據，會阻塞
                Message msg = new Message();
                Bundle b = new Bundle();
                b.putString("data", messageRecv);
                msg.setData(b);
                handler.sendMessage(msg);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

下面是xml頁面代碼

<?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"
    tools:context=".SocketActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp">
            <Button
                android:id="@+id/bt_getAdress"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="獲取IP地址"/>

            <TextView
                android:id="@+id/tv_adress"
                android:layout_width="200dp"
                android:layout_height="match_parent"
                android:layout_marginLeft="15dp"
                android:textSize="20dp"
                android:gravity="center"/>
        </LinearLayout>
        <Button
            android:id="@+id/bt_startServer"
            android:text="啓動服務"
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
        <EditText
            android:id="@+id/et_message"
            android:layout_marginTop="10dp"
            android:hint="請輸入發送信息"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
        <Button
            android:id="@+id/bt_connect"
            android:text="連接發送"
            android:layout_marginTop="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <TextView
            android:id="@+id/tv_reply"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:text="服務端返回消息："
            android:textSize="30sp"/>
    </LinearLayout>
</LinearLayout>

客戶端跟服務器進行通信之前記得先啓動服務器，如果端口被佔用需要換個端口。