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Android客户端利用Socket连接服务器的大概思路如下:
客户端首次连接服务器:
socket = new Socket(); SocketAddress address = new InetSocketAddress(svrHost, svrPort); socket.connect(address, TIME_OUT); socket.setSoTimeout(TIME_OUT); in = new BufferedReader(new InputStreamReader( socket.getInputStream())); out = new PrintWriter(new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())), true);
连接服务器之后,调用注册或者登录,获取连接的token。 以后每次的连接获取信息都要带上约定的token。
连接建立以后,socket不必关闭,毕竟每次connect也浪费资源,可以一直挂住等待服务端的推送或者心跳等消息。
while (!exitSocket) { try { if (!socket.isClosed() && socket.isConnected() && !socket.isInputShutdown()) { char[] lenBuffer = new char[13]; int len = 0; try { len = in.read(lenBuffer); } catch (Exception e) { Utils.debug("SocketSvr socket read timeout"); stopSocketByException(true); }
每次的请求,server端返回的数据都包含在lenBuffer中,一般是约定好的json或者是其他格式的信息。
整体思路是和TCP是一样的,更多的问题出现在细节处理上和socket的生命周期的维护上。
比如如果断网或者出现异常导致socket出现exception,这时可能需要把当前的socket关闭(timeoutException应该不需要重启),然后重新启动新的socket,但是对于终端用户来说,应当避免的是让用户感觉到有界面的异动,需要立即重新连接server。
Android客户端通过socket与服务器通信实例
由于Android里面可以完全使用java.io.*包和java.net.*包,那么,实际上,逻辑部分与J2SE没有区别。只是UI代码不一样。
Android客户端通过socket与服务器通信分为下面5步:
(1)通过IP地址和端口实例化Socket,请求连接服务器;
socket = new Socket("10.14.114.127",54321); //IP:10.14.114.127,端口54321
(2)获取Socket流以进行读写,并把流包装进BufferWriter或者PrintWriter
PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
这里涉及了三个类:socket.getOutputStream得到socket的输出字节流,OutputStreamWriter是字节流向字符流转换的桥梁,BufferWriter是字符流,然后再包装进PrintWriter。
(3)对Socket进行读写
out.println(message);
(4)关闭打开的流
out.close();
完整工程代码如下:
package com.yarin.android.Examples_08_04; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.Socket; import android.app.Activity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class Activity01 extends Activity { private final String DEBUG_TAG = "Activity01"; private TextView mTextView = null; private EditText mEditText = null; private Button mButton = null; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mButton = (Button)findViewById(R.id.Button01); mTextView = (TextView)findViewById(R.id.TextView01); mEditText = (EditText)findViewById(R.id.EditText01); //登陆 mButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { Socket socket = null; String message = mEditText.getText().toString() + "/r/n"; try { //创建Socket // socket = new Socket("192.168.1.110",54321); socket = new Socket("10.14.114.127",54321); //IP:10.14.114.127,端口54321 //向服务器发送消息 PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true); out.println(message); //接收来自服务器的消息 BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); String msg = br.readLine(); if ( msg != null ) { mTextView.setText(msg); } else { mTextView.setText("数据错误!"); } //关闭流 out.close(); br.close(); //关闭Socket socket.close(); } catch (Exception e) { // TODO: handle exception Log.e(DEBUG_TAG, e.toString()); } } }); } }
布局文件main.xml
AndroidManifest.xml文件如下
当然,还有服务器端得代码
package com.yarin.android.Examples_08_04; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.ServerSocket; import java.net.Socket; public class Server implements Runnable { public void run() { try { //创建ServerSocket ServerSocket serverSocket = new ServerSocket(54321); while (true) { //接受客户端请求 Socket client = serverSocket.accept(); System.out.println("accept"); try { //接收客户端消息 BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream())); String str = in.readLine(); System.out.println("read:" + str); //向服务器发送消息 PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(client.getOutputStream())),true); out.println("server message"); //关闭流 out.close(); in.close(); } catch (Exception e) { System.out.println(e.getMessage()); e.printStackTrace(); } finally { //关闭 client.close(); System.out.println("close"); } } } catch (Exception e) { System.out.println(e.getMessage()); } } //main函数,开启服务器 public static void main(String a[]) { Thread desktopServerThread = new Thread(new Server()); desktopServerThread.start(); } }
先开启服务器代码,
java Server即可
然后启动android模拟器。运行结果
这是Android客户端。输入12345,点击发送:
这是服务器端收到的消息