android实现Socket通信一

最新推荐文章于 2025-06-29 15:28:32 发布

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最新推荐文章于 2025-06-29 15:28:32 发布

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本文链接：https://blog.youkuaiyun.com/dami_lixm/article/details/47731245

本文详细介绍了如何使用Java的Socket API在Android客户端与服务器端之间建立TCP连接并进行数据交换，包括服务端如何监听指定端口接受连接，客户端如何发起连接并发送、接收数据。同时讨论了端口选择的重要性以及阻塞操作的应用。

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两个应用间实现通过SOCKET进行通信。

主要是通过socket和serversocket，这两个东西怎么用呢？

1、在服务端通过serversocket监听一个端口，这个端口用于接收客户单发送的消息， ServerSocket server = new ServerSocket(8081)。

2、在服务端在建立一个socket，用于和客户端进行通信 Socket socket = server.accept()。当客户单的socket建立成功时（Socket socket=new Socket("127.0.0.1",8081)），服务端的socket也就生成了。

3、两端的socket通过输入输出流来进行通信：

getInputStream方法获得网络连接输入，同时返回一个IutputStream对象实例.(获得另一输入过来的信息)。

getOutputStream方法连接的另一端将得到输入，同时返回一个OutputStream对象实例。(可以用于服务端把信息写回到客户端去)。

关于阻塞，两个阻塞的地方：

1、server.accept() ,直到有客户端的socket连上来。

2、br.readLine()，直到对方向输出流中写入东西时。

关于端口：

在选择端口时，必须小心。每一个端口提供一种特定的服务，只有给出正确的端口，才能获得相应的服务。 0~1023的端口号为系统所保留，例如http服务的端口号为80,telnet服务的端口号为21,ftp服务的端口号为23, 所以我们在选择端口号时，最好选择一个大于1023的数以防止发生冲突。

客户端的代码：

package com.example.socket_client;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.ServerSocket;
import java.net.Socket;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

	private final static String TAG = "SOCKET_CLIENT";
	EditText input = null;
	Button btnSend = null;
	ServerSocket serverSocket = null;
	public final static int MSG_FROM_SERVER = 1002;
	
	private boolean isOk = true;
	
	private Handler mHandler = new Handler(){
		public void handleMessage(android.os.Message msg) {
			if(msg.what == MSG_FROM_SERVER){
				input.setText(null);
				Toast.makeText(MainActivity.this, "收到了服务器消息 :" + (String)msg.obj, Toast.LENGTH_LONG).show();
			}
		};
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		input = (EditText)findViewById(R.id.id_input);
		btnSend = (Button)findViewById(R.id.btnSend);
		btnSend.setOnClickListener(this);
		try {
			serverSocket = new ServerSocket(8082);
			new Thread(new ReceiverRunnable()).start();
		}
		catch (IOException e) {
			Log.d(TAG, "IOException = " + e);
		}
	}

	@Override
	public void onClick(View arg0) {
		new Thread(){
			public void run(){
				try{
					Socket socket=new Socket("127.0.0.1",8081);// 连接服务器端
					// 用法发送消息到服务器端
					Writer writer = new OutputStreamWriter(socket.getOutputStream());
					String inputStr = input.getText().toString();
					Log.d(TAG, "inputStr = " + inputStr);
					if(inputStr != null){
						writer.write(inputStr);
						writer.flush();
					}
					writer.close(); //关闭Socket输出流
					socket.close(); //关闭Socket
				}catch(Exception e) {
					Log.d(TAG, "", e);
				}
			}
		}.start();
	}
	
	class ReceiverRunnable implements Runnable {
		@Override
		public void run() {

			while (isOk) {
				try {
					if(serverSocket == null || serverSocket.isClosed()){
						break;
					}
					Socket socket = serverSocket.accept();
					// 由Socket对象得到输入流，并构造相应的BufferedReader对象 读取服务器端发回来的消息
					BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
					String msgFromServer = br.readLine();
					if (msgFromServer != null) {
						Message msg = mHandler.obtainMessage(MSG_FROM_SERVER);
						msg.obj = msgFromServer;
						mHandler.sendMessage(msg);
					}
					br.close(); // 关闭Socket输入流
					socket.close();
				}
				catch (IOException e) {
					isOk = false;
					Log.d(TAG, "ReceiverRunnable IOException", e);
				}
			}

		}

	}

	@Override
	protected void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
		try {
			isOk = false;
			serverSocket.close();
		}
		catch (IOException e) {
			Log.d(TAG, "onDestroy IOException", e);
		}
	}
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.socket_client.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <EditText
        android:id="@+id/id_input"
        android:layout_width="match_parent"
        android:layout_height="50dp" />

    <Button
        android:id="@+id/btnSend"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_below="@id/id_input"
        android:text="send" />

</RelativeLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.socket_client"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

服务端代码：

MainActivity

package com.example.socket_server;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;

public class MainActivity extends ActionBarActivity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		// start service
		Intent intent = new Intent(MainActivity.this,
				SocketServer.class);
		this.startService(intent);
	}
}

SocketServer

package com.example.socket_server;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;

public class SocketServer extends Service {

	public final static int MSG_RECEIVED = 1001;
	private final static String TAG = "SOCKET_SERVER";
	/**
	 * 显示客户单输入的信息
	 */
	public Handler handler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
			switch (msg.what) {
				case MSG_RECEIVED:
					Toast.makeText(SocketServer.this, "From Server : " + (String) msg.obj, Toast.LENGTH_SHORT).show();
					break;
			}
		}
	};

	@Override
	public IBinder onBind(Intent arg0) {
		return null;
	}

	@Override
	public void onCreate() {
		super.onCreate();
		final int port = 8081;

		new Thread() {
			public void run() {
				ServerSocket server = null;
				try {
					/**
					 * 服务端监听本机的一个端口，等待客户端向这个端口发送的消息
					 */
					server = new ServerSocket(port); // TODO 这个端口是干啥用的？必须要指定吗？
					while (true) {
						// server尝试接收其他Socket的连接请求，server的accept方法是阻塞式的
						Socket socket = server.accept(); // accept一个socket，和客户单建立连接
						// 每接收到一个Socket就建立一个新的线程来处理它
						new Thread(new RecevierRunnable(socket)).start();
					}
				}
				catch (IOException e) {
					e.printStackTrace();
				}
			}
		}.start();
	}

	/**
	 * 独立的线程来接收消息
	 * 
	 * @author lixiaoming
	 * 
	 */
	class RecevierRunnable implements Runnable {
		Socket socket;
		String ip;

		public RecevierRunnable(Socket socket) {
			this.socket = socket;
			this.ip = socket.getInetAddress().getHostAddress();
		}

		public void run() {
			try {
				receivedMsgBySocket();
			}
			catch (Exception e) {
				e.printStackTrace();
			}
		}

		private void receivedMsgBySocket() throws Exception {
			Log.d(TAG, "receivedMsgBySocket() start");
			BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			String strFromClient = br.readLine();
			Message msg = handler.obtainMessage(MSG_RECEIVED);
			msg.obj = strFromClient;
			handler.sendMessage(msg);
			br.close();
			socket.close();
			sendMsgToClient(ip,8082,strFromClient);
			Log.d(TAG, "receivedMsgBySocket() end");
		}
		
		private void sendMsgToClient(String ip,int prot,String msg){
			Log.d(TAG, "sendMsgToClient() start , ip = " + ip);
			try {
				Socket toClientSocket = new Socket(ip,prot);
				// 读完后写一句
				Writer writer = new OutputStreamWriter(toClientSocket.getOutputStream(), "UTF-8");
				writer.write("你好，客户端:" + ip + ",我是服务端，我已经收到你的消息了，你说 ：" + msg);
				writer.flush();
				writer.close();
				toClientSocket.close();
			}
			catch (UnknownHostException e) {
				Log.d(TAG, "sendMsgToClient () UnknownHostException",e);
			}
			catch (IOException e) {
				Log.d(TAG, "sendMsgToClient () IOException",e);
			}
			Log.d(TAG, "sendMsgToClient() start");
		}
	}
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.socket_server.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.socket_server"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service 
            android:name = "com.example.socket_server.SocketServer"></service>
    </application>

</manifest>