【Android】使用Socket实现跨设备通讯

1 Socket 简介

​ Socket（套接字）是应用层与 TCP/IP 协议通信的中间软件抽象层，它是一组接口，用户只需面向 Socket 编程，即可实现跨设备（网络）通讯。

​ Socket 是 java 里的东西，不是 Android 特有的，使用 Socket 需要导入的类如下。

java.net.ServerSocket
java.net.Socket

​ （1）服务端主要接口调用

// 获取 socket
mServerSocket = new ServerSocket(port)
// port 为端口号，取值：0~65535间的整数，前1024个端口号为固定端口，一般不提供给程序员使用，之后为注册端口，为避免端口冲突，建议 port 值取大点
mSocket = mServerSocket.accept() //调用此方法会阻塞线程，建议在子线程中执行

// 读取对端数据
in = mSocket.getInputStream()
byte[] bt = new byte[50]
in.read(bt)

// 向对端发送数据
out = new PrintWriter(mSocket.getOutputStream())
out.print(content)
out.flush()

​ （2）客户端主要接口调用

// 获取 socket
mSocket = new Socket(ip, port) //调用此方法会阻塞线程，建议在子线程中执行
// ip 为服务端设备 ip 地址
// port 为端口号，取值：0~65535间的整数，前1024个端口号为固定端口，一般不提供给程序员使用，之后为注册端口，为避免端口冲突，建议 port 值取大点

// 读取对端数据
in = mSocket.getInputStream()
byte[] bt = new byte[50]
in.read(bt)

// 向对端发送数据
out = new PrintWriter(mSocket.getOutputStream())
out.print(content)
out.flush()

​ 本文全部代码见→使用Socket实现跨设备通讯

2 项目结构

​ 注意：2个设备必须在局域网中（连同一个wifi ）

3 服务端（socket_S）

​ Server.java

package com.zhyan8.socket_s;

import android.os.Handler;
import android.os.Message;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Server{
    private ServerSocket mServerSocket;
    private Socket mSocket;
    private Handler mHandler;
    private InputStream in;
    private PrintWriter out;
    private Object lock = new Object();

    public Server(Handler handler, int port){
        mHandler = handler;
        try {
            mServerSocket = new ServerSocket(port);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void connect() {
        new Thread() {
            @Override
            public void run() {
                try {
                    synchronized (lock) {
                        if (mSocket!=null) {
                            return;
                        }
                        mSocket = mServerSocket.accept();
                        in = mSocket.getInputStream();
                        out = new PrintWriter(mSocket.getOutputStream());
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public void begin_listen() {
        while (mSocket==null) {
            connect();
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        new Thread() {
            @Override
            public void run() {
                try {
                    while (!mSocket.isClosed()) {
                        byte[] bt = new byte[50];
                        in.read(bt);
                        String content = new String (bt, "UTF-8" );
                        if (content!=null && !content.equals("")) {
                            Message msg = new Message();
                            msg.obj = content;
                            mHandler.sendMessage(msg);
                        }
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public void send_msg(final String content) {
        new Thread() {
            @Override
            public void run() {
                out.print(content);
                out.flush ();
            }
        }.start();
    }
}

​ MainActivity.java

package com.zhyan8.socket_s;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Server mServer;
    private EditText et_msg;
    private Button btn_send;
    private TextView tv_msg;

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

    private void init() {
        et_msg = (EditText) findViewById(R.id.et_msg);
        btn_send = (Button) findViewById(R.id.btn_send);
        tv_msg = (TextView) findViewById(R.id.tv_msg);
        btn_send.setOnClickListener(cl);
        mServer = new Server(mHandler, 1111);
        mServer.begin_listen();
    }

    private View.OnClickListener cl =  new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String content = et_msg.getText().toString().trim();
            if (content!=null && !content.equals("")) {
                mServer.send_msg(content);
            }
        }
    };

    private Handler mHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            String content = (String) msg.obj;
            tv_msg.setText(content);
        }
    };
}

​ activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context="com.zhyan8.socket_s.MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="horizontal"
        android:gravity="center_vertical">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="接收的消息："
            android:textSize="20sp"
            android:gravity="center_vertical"/>
        <TextView
            android:id="@+id/tv_msg"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:textSize="20sp"
            android:gravity="center_vertical"/>
    </LinearLayout>

    <EditText
        android:id="@+id/et_msg"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:textSize="30sp"
        android:background="#ffcc66"/>

    <Button
        android:id="@+id/btn_send"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:text="发送"
        android:textSize="30sp"
        android:layout_marginTop="30dp"/>
</LinearLayout>

​ 界面如下：

​ 在 AndroidManifest.xml 文件的 manifest 标签下（与 application 同级）添加如下权限：

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

4 客户端（socket_C）

​ Client.java

package com.zhyan8.socket_c;

import android.os.Handler;
import android.os.Message;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.Socket;

public class Client{
    private Socket mSocket;
    private Handler mHandler;
    private InputStream in;
    private PrintWriter out;
    private String ip;
    private int port;
    private Object lock = new Object();

    Client(Handler handler, String ip, int port) {
        mHandler = handler;
        this.ip = ip;
        this.port = port;
    }

    private void connect() {
        new Thread() {
            @Override
            public void run() {
                try {
                    synchronized (lock) {
                        if (mSocket!=null) {
                            return;
                        }
                        mSocket = new Socket(ip, port);
                        in = mSocket.getInputStream();
                        out = new PrintWriter(mSocket.getOutputStream());
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public void begin_listen() {
        while (mSocket==null) {
            connect();
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        new Thread() {
            @Override
            public void run() {
                try {
                    while (!mSocket.isClosed()){
                        byte[] bt = new byte[50];
                        in.read(bt);
                        String content = new String (bt, "UTF-8" );
                        if (content!=null && !content.equals("")) {
                            Message msg = new Message();
                            msg.obj = content;
                            mHandler.sendMessage(msg);
                        }
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public void send_msg(final String content) {
        new Thread() {
            @Override
            public void run() {
                out.print(content);
                out.flush();
            }
        }.start();
    }
}

​ MainActivity.java

package com.zhyan8.socket_c;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Client mClient;
    private EditText et_msg;
    private Button btn_send;
    private TextView tv_msg;

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

    private void init() {
        et_msg = (EditText) findViewById(R.id.et_msg);
        btn_send = (Button) findViewById(R.id.btn_send);
        tv_msg = (TextView) findViewById(R.id.tv_msg);
        btn_send.setOnClickListener(cl);
        mClient = new Client(mHandler, "192.168.0.104", 1111);
        mClient.begin_listen();
    }

    private View.OnClickListener cl =  new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String content = et_msg.getText().toString().trim();
            if (content!=null && !content.equals("")) {
                mClient.send_msg(content);
            }
        }
    };

    private Handler mHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            String content = (String) msg.obj;
            tv_msg.setText(content);
        }
    };
}

​ activity_main.xml 同第3节。

​ 在 AndroidManifest.xml 文件的 manifest 标签下（与 application 同级）添加如下权限：

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

5 效果展示

​ 客户端：

​ 服务端：

​ 声明：本文转自【Android】使用Socket实现跨设备通讯