[轉載來源](http://blog.csdn.net/wuchuanpingstone/article/details/6617276#comments)
android客戶端通過socket與服務器進行通信可以分為以下幾步：
應用程序與服務器通信可以采用兩種模式：TCP可靠通信 和UDP不可靠通信。
（1）通過IP地址和端口實例化Socket，請求連接服務器：
socket = new Socket(HOST, PORT);?? //host:為服務器的IP地址? port：為服務器的端口號
（2）獲取Socket流以進行讀寫，并把流包裝進BufferWriter或者PrintWriter：
PrintWriter?out?=?new?PrintWriter(?new?BufferedWriter(?new?OutputStreamWriter(socket.getOutputStream())),true);??
這里涉及了三個類：socket.getOutputStream得到socket的輸出字節流，OutputStreamWriter是字節流向字符流轉換的橋梁，BufferWriter是字符流，然后再包裝進PrintWriter。
（3）對Socket進行讀寫
~~~
??? if (socket.isConnected()) {
?????????????????? if (!socket.isOutputShutdown()) {
?????????????????????? out.println(msg);
?????????????????? }
?????????????? }
~~~
（4）關閉打開的流
`???? out.close();`
在寫代碼的過程中一定要注意對socket? 輸入流? 輸出流的關閉
下面是一個簡單的例子：
main.xml
~~~
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="@+id/TextView"
android:singleLine="false"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<EditText android:hint="content"
android:id="@+id/EditText01"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</EditText>
<Button
android:text="send"
android:id="@+id/Button02"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</Button>
</LinearLayout>
~~~
下面是android客戶端的源代碼：
~~~
package com.example.socketdemo;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.StrictMode;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@SuppressLint("NewApi")
public class SocketDemo extends Activity implements Runnable {
private TextView tv_msg = null;
private EditText ed_msg = null;
private Button btn_send = null;
// private Button btn_login = null;
private static final String HOST = "192.168.1.223";
private static final int PORT = 9999;
private Socket socket = null;
private BufferedReader in = null;
private PrintWriter out = null;
private String content = "";
/**Called when the activity is first created. */
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_socket_demo);
////Android 2.3及以上調用嚴苛模式
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
}
tv_msg = (TextView) findViewById(R.id.TextView);
ed_msg = (EditText) findViewById(R.id.EditText01);
// btn_login = (Button) findViewById(R.id.Button01);
btn_send = (Button) findViewById(R.id.Button02);
try {
socket = new Socket(HOST, PORT);
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream())), true);
} catch (IOException ex) {
ex.printStackTrace();
ShowDialog("login exception" + ex.getMessage());
}
btn_send.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
String msg = ed_msg.getText().toString();
if (socket.isConnected()) {
if (!socket.isOutputShutdown()) {
out.println(msg);
}
}
}
});
new Thread(SocketDemo.this).start();
}
public void ShowDialog(String msg) {
new AlertDialog.Builder(this).setTitle("notification").setMessage(msg)
.setPositiveButton("ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
}).show();
}
public void run() {
try {
while (true) {
if (socket.isConnected()) {
if (!socket.isInputShutdown()) {
if ((content = in.readLine()) != null) {
content += "\n";
mHandler.sendMessage(mHandler.obtainMessage());
} else {
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
super.handleMessage(msg);
tv_msg.setText(tv_msg.getText().toString() + content);
}
};
}
~~~
下面是服務器端的java代碼：
~~~
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Main {
private static final int PORT = 9999;
private List<Socket> mList = new ArrayList<Socket>();
private ServerSocket server = null;
private ExecutorService mExecutorService = null; //thread pool
public static void main(String[] args) {
new Main();
}
public Main() {
try {
server = new ServerSocket(PORT);
mExecutorService = Executors.newCachedThreadPool(); //create a thread pool
System.out.print("server start ...");
Socket client = null;
while(true) {
client = server.accept();
mList.add(client);
mExecutorService.execute(new Service(client)); //start a new thread to handle the connection
}
}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 = "user" +this.socket.getInetAddress() + "come toal:"
+mList.size();
this.sendmsg();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void run() {
// TODO Auto-generated method stub
try {
while(true) {
if((msg = in.readLine())!= null) {
if(msg.equals("exit")) {
System.out.println("ssssssss");
mList.remove(socket);
in.close();
msg = "user:" + socket.getInetAddress()
+ "exit total:" + mList.size();
socket.close();
this.sendmsg();
break;
} else {
msg = socket.getInetAddress() + ":" + msg;
this.sendmsg();
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
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())),true);
pout.println(msg);
}catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
~~~
注意在AndroidManifest.xml中加入對網絡的訪問權限
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
在寫代碼的過程中一定要注意對套接字和輸入/輸出流的關閉
