本节引言:

上一节的概念课枯燥无味是吧,不过总有点收获是吧,本节开始我们来研究基于TCP协议的Socket
通信,先来了解下Socket的概念,以及Socket通信的模型,实现Socket的步骤,以及作为Socket服务
端与客户端的两位各做要做什么事情!好的,我们由浅入深来扣这个Socket吧!


1.什么是Socket?


2.Socket通信模型:

Socket通信实现步骤解析

Step 1:创建ServerSocket和Socket

Step 2:打开连接到的Socket的输入/输出流

Step 3:按照协议对Socket进行读/写操作

Step 4:关闭输入输出流,以及Socket

好的,我们接下来写一个简单的例子,开启服务端后,客户端点击按钮然后链接服务端,
并向服务端发送一串字符串,表示通过Socket链接上服务器~


3.Socket服务端的编写:

服务端要做的事有这些

Step 1:创建ServerSocket对象,绑定监听的端口

Step 2:调用accept()方法监听客户端的请求

Step 3:连接建立后,通过输入流读取客户端发送的请求信息

Step 4:通过输出流向客户端发送响应信息

Step 5:关闭相关资源

代码实现

直接在Eclipse下创建一个Java项目,然后把Java代码贴进去即可!

public class SocketServer {
	public static void main(String[] args) throws IOException {
		//1.创建一个服务器端Socket,即ServerSocket,指定绑定的端口,并监听此端口
		ServerSocket serverSocket = new ServerSocket(12345);
		InetAddress address = InetAddress.getLocalHost();
		String ip = address.getHostAddress();
		Socket socket = null;
		//2.调用accept()等待客户端连接
		System.out.println("~~~服务端已就绪,等待客户端接入~,服务端ip地址: " + ip);
		socket = serverSocket.accept();
		//3.连接后获取输入流,读取客户端信息
		InputStream is=null;
		InputStreamReader isr=null;
		BufferedReader br=null;
		OutputStream os=null;
		PrintWriter pw=null;
		is = socket.getInputStream();     //获取输入流
		isr = new InputStreamReader(is,"UTF-8");
		br = new BufferedReader(isr);
		String info = null;
		while((info=br.readLine())!=null){//循环读取客户端的信息
			System.out.println("客户端发送过来的信息" + info);
		}
		socket.shutdownInput();//关闭输入流
		socket.close();
	}
}

然后我们把代码run起来,控制台会打印:

好的,接下来到Android客户端了!


4.Socket客户端的编写:

客户端要做的事有这些

Step 1:创建Socket对象,指明需要链接的服务器的地址和端号

Step 2:链接建立后,通过输出流向服务器发送请求信息

Step 3:通过输出流获取服务器响应的信息

Step 4:关闭相关资源

代码实现

MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn_accept = (Button) findViewById(R.id.btn_accept);
        btn_accept.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        new Thread() {
            @Override
            public void run() {
                try {
                    acceptServer();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    private void acceptServer() throws IOException {
        //1.创建客户端Socket,指定服务器地址和端口
        Socket socket = new Socket("172.16.2.54", 12345);
        //2.获取输出流,向服务器端发送信息
        OutputStream os = socket.getOutputStream();//字节输出流
        PrintWriter pw = new PrintWriter(os);//将输出流包装为打印流
        //获取客户端的IP地址
        InetAddress address = InetAddress.getLocalHost();
        String ip = address.getHostAddress();
        pw.write("客户端:~" + ip + "~ 接入服务器!!");
        pw.flush();
        socket.shutdownOutput();//关闭输出流
        socket.close();
    }
}

因为Android不允许在主线程(UI线程)中做网络操作,所以这里需要我们自己
另开一个线程来连接Socket!

运行结果:

点击按钮后,服务端控制台打印:


5.增强版案例:小猪简易聊天室

只是点击个按钮,然后服务器返回一串信息,肯定是很无趣的是吧,接下来我们来
搭建一个超简单的聊天室,我们需要用到线程池,存储Socket链接的集合,我们还需要
字节写一个线程,具体的我们在代码中来体会!

实现的效果图:

先把我们的服务端跑起来:

接着把我们的程序分别跑到两台模拟器上:

接下来我们来写代码:

首先是服务端,就是将读写socket的操作放到自定义线程当中,创建ServerSocket后,循环
调用accept方法,当有新客户端接入,将socket加入集合当中,同时在线程池新建一个线程!

另外,在读取信息的方法中,对输入字符串进行判断,如果为bye字符串,将socket从集合中
移除,然后close掉!

Server.java:

public class Server {
	//定义相关的参数,端口,存储Socket连接的集合,ServerSocket对象
	//以及线程池
	private static final int PORT = 12345;
	private List mList = new ArrayList();
	private ServerSocket server = null;
	private ExecutorService myExecutorService = null;
	
	
	public static void main(String[] args) {
		new Server();
	}

	public Server()
	{
		try
		{
			server = new ServerSocket(PORT);
			//创建线程池
			myExecutorService = Executors.newCachedThreadPool();
			System.out.println("服务端运行中...\n");
			Socket client = null;
			while(true)
			{
				client = server.accept();
				mList.add(client);
				myExecutorService.execute(new Service(client));
			}
			
		}catch(Exception e){e.printStackTrace();}
	}
	
	class Service implements Runnable
	{
		private Socket socket;
		private BufferedReader in = null;
		private String msg = "";
		
		public Service(Socket socket) {
			this.socket = socket;
			try
			{
				in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
				 msg = "用户:" +this.socket.getInetAddress() + "~加入了聊天室"  
	                        +"当前在线人数:" +mList.size();  
				this.sendmsg();
			}catch(IOException e){e.printStackTrace();}
		}
		
		
		
		@Override
		public void run() {
			try{
				while(true)
				{
					if((msg = in.readLine()) != null)
					{
						if(msg.equals("bye"))
						{
							System.out.println("~~~~~~~~~~~~~");
							mList.remove(socket);
                            in.close();
                            msg = "用户:" + socket.getInetAddress()  
                                    + "退出:" +"当前在线人数:"+mList.size();  
                            socket.close();  
                            this.sendmsg();  
                            break;
						}else{
							msg = socket.getInetAddress() + "   说: " + msg;  
                            this.sendmsg(); 
						}
					}
				}
			}catch(Exception e){e.printStackTrace();}
		}
		
		//为连接上服务端的每个客户端发送信息
		public void sendmsg()
		{
			System.out.println(msg);
			int num = mList.size();
			for(int index = 0;index < num;index++)
			{
				Socket mSocket = mList.get(index);  
                PrintWriter pout = null;  
                try {  
                    pout = new PrintWriter(new BufferedWriter(  
                            new OutputStreamWriter(mSocket.getOutputStream(),"UTF-8")),true);  
                    pout.println(msg);  
                }catch (IOException e) {e.printStackTrace();}  
			}
		}
		
	}
}

接着到客户端,客户端的难点在于要另外开辟线程的问题,因为Android不允许直接在
主线程中做网络操作,而且不允许在主线程外的线程操作UI,这里的做法是自己新建
一个线程,以及通过Hanlder来更新UI,实际开发不建议直接这样做!!!

布局文件:activity_main.xml



    
    
    
    

MainActivity.java:

public class MainActivity extends AppCompatActivity implements Runnable {

    //定义相关变量,完成初始化
    private TextView txtshow;
    private EditText editsend;
    private Button btnsend;
    private static final String HOST = "172.16.2.54";
    private static final int PORT = 12345;
    private Socket socket = null;
    private BufferedReader in = null;
    private PrintWriter out = null;
    private String content = "";
    private StringBuilder sb = null;

    //定义一个handler对象,用来刷新界面
    public Handler handler = new Handler() {
        public void handleMessage(Message msg) {
            if (msg.what == 0x123) {
                sb.append(content);
                txtshow.setText(sb.toString());
            }
        }

        ;
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sb = new StringBuilder();
        txtshow = (TextView) findViewById(R.id.txtshow);
        editsend = (EditText) findViewById(R.id.editsend);
        btnsend = (Button) findViewById(R.id.btnsend);

        //当程序一开始运行的时候就实例化Socket对象,与服务端进行连接,获取输入输出流
        //因为4.0以后不能再主线程中进行网络操作,所以需要另外开辟一个线程
        new Thread() {

            public void run() {
                try {
                    socket = new Socket(HOST, PORT);
                    in = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));
                    out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
                            socket.getOutputStream())), true);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();

        //为发送按钮设置点击事件
        btnsend.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                String msg = editsend.getText().toString();
                if (socket.isConnected()) {
                    if (!socket.isOutputShutdown()) {
                        out.println(msg);
                    }
                }
            }
        });
        new Thread(MainActivity.this).start();
    }

    //重写run方法,在该方法中输入流的读取
    @Override
    public void run() {
        try {
            while (true) {
                if (socket.isConnected()) {
                    if (!socket.isInputShutdown()) {
                        if ((content = in.readLine()) != null) {
                            content += "\n";
                            handler.sendEmptyMessage(0x123);
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

本节小结:

好的,本节给大家讲解了基于TCP的Socket通信,文中介绍了Socket通信的模型,实现了
一个简单的Socket通信例子,以及写了一个增强版的实例:小猪聊天室,相信会对刚涉及
Socket编程的你带来便利~,谢谢~