Socket是TCP/IP协议上的一种通信，在通信的两端各建立一个Socket，从而在通信的两端之间形成网络虚拟链路。一旦建立了虚拟的网络链路，两端的程序就可以通过虚拟链路进行通信。
Client A发信息给 Client B ,A的信息首先发送信息到服务器Server ，Server接受到信息后再把A的信息广播发送给所有的Clients
首先我们要在服务器建立一个ServerSocket ，ServerSocket对象用于监听来自客户端的Socket连接，如果没有连接，它将一直处于等待状态。
Socket accept()：如果接收到一个客户端Socket的连接请求，该方法将返回一个与客户端Socket对应的Socket
Server示例：
//创建一个ServerSocket，用于监听客户端Socket的连接请求
ServerSocket ss = new ServerSocket(30000);
//采用循环不断接受来自客户端的请求
while (true){
//每当接受到客户端Socket的请求，服务器端也对应产生一个Socket
Socket s = ss.accept();
//下面就可以使用Socket进行通信了
...
}
客户端通常可使用Socket的构造器来连接到指定服务器
Client示例:
//创建连接到服务器、30000端口的Socket
Socket s = new Socket("192.168.2.214" , 30000);
//下面就可以使用Socket进行通信了
...
这样Server和Client就可以进行一个简单的通信了
当然，我们要做的是多客户，所以每当客户端Socket连接到该ServerSocket之后，程序将对应Socket加入clients集合中保存，并为该Socket启动一条线程，该线程负责处理该Socket所有的通信任务
//定义保存所有Socket的ArrayList
public static ArrayList<Socket> clients = new ArrayList<Socket>();
当服务器线程读到客户端数据之后，程序遍历clients集合，并将该数据向clients集合中的每个Socket发送一次。这样就可以实现一个聊天室的功能了
下面来看看整个功能的demo
先建立一个Java工程，把Server.java运行起来，然后再运行手机模拟器
服务器打印信息：
程序文件结构：
嘿嘿，大家别笑我，我的JAVA水平还是初学者，很多地方都觉得很菜，代码规格程度：小学。 有待提高啊!
1.先看看主Activity : SocketmsgActivity.java
public class SocketmsgActivity extends Activity {
/** Called when the activity is first created. */
private SQLiteDatabase db;
Thread thread = null;
Socket s = null;
private InetSocketAddress isa = null;
DataInputStream dis = null;
DataOutputStream dos = null;
private String reMsg=null;
private Boolean isContect = false;
private EditText chattxt;
private EditText chatbox;
private Button chatok;
private String chatKey="SLEEKNETGEOCK4stsjeS";
private String name=null,ip=null,port=null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
chattxt = (EditText)findViewById(R.id.chattxt);
chatbox = (EditText)findViewById(R.id.chatbox);
chatok = (Button)findViewById(R.id.chatOk);
chatbox.setCursorVisible(false);
chatbox.setFocusable(false);
chatbox.setFocusableInTouchMode(false);
chatbox.setGravity(2);
//初始化，创建数据库来储存用户信息
InitDatabase();
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
try {
Cursor cursor = db.query("config", new String[]{"ip","name","port"},null,null, null, null, null);
while(cursor.moveToNext()){
name = cursor.getString(cursor.getColumnIndex("name"));
ip = cursor.getString(cursor.getColumnIndex("ip"));
port = cursor.getString(cursor.getColumnIndex("port"));
}
cursor.close();
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.toString());
}
db.close();
//设置连接
if(ip==null || port==null){
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
}
//设置名称
else if(name==null){
Intent intent = new Intent(SocketmsgActivity.this,IniuserActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
}else{
connect();
chatok.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String str = chattxt.getText().toString().trim();
System.out.println(s);
try {
dos.writeUTF(chatKey+"name:"+name+"end;"+str);
chattxt.setText("");
}catch (SocketTimeoutExceptione) {
System.out.println("連接超時，服務器未開啟或IP錯誤");
Toast.makeText(SocketmsgActivity.this, "連接超時，服務器未開啟或IP錯誤", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("連接超時，服務器未開啟或IP錯誤");
Toast.makeText(SocketmsgActivity.this, "連接超時，服務器未開啟或IP錯誤", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
e.printStackTrace();
}
}
});
}
}
private Runnable doThread = new Runnable() {
public void run() {
System.out.println("running!");
ReceiveMsg();
}
};
public void connect() {
try {
s = new Socket();
isa = new InetSocketAddress(ip,Integer.parseInt(port));
s.connect(isa,5000);
if(s.isConnected()){
dos = new DataOutputStream (s.getOutputStream());
dis = new DataInputStream (s.getInputStream());
dos.writeUTF(chatKey+"online:"+name);
/**
* 这里是关键，我在此耗时8h+
* 原因是 子线程不能直接更新UI
* 为此，我们需要通过Handler物件，通知主线程Ui Thread来更新界面。
*
*/
thread = new Thread(null, doThread, "Message");
thread.start();
System.out.println("connect");
isContect=true;
}
}catch (UnknownHostException e) {
System.out.println("連接失敗");
Toast.makeText(SocketmsgActivity.this, "連接失敗", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
e.printStackTrace();
}catch (SocketTimeoutExceptione) {
System.out.println("連接超時，服務器未開啟或IP錯誤");
Toast.makeText(SocketmsgActivity.this, "連接超時，服務器未開啟或IP錯誤", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
e.printStackTrace();
}catch (IOException e) {
System.out.println("連接失敗");
e.printStackTrace();
}
}
public void disConnect() {
if(dos!=null){
try {
dos.writeUTF(chatKey+"offline:"+name);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 线程监视Server信息
*/
private void ReceiveMsg() {
if (isContect) {
try {
while ((reMsg = dis.readUTF()) != null) {
System.out.println(reMsg);
if (reMsg != null) {
try {
Message msgMessage = new Message();
msgMessage.what = 0x1981;
handler.sendMessage(msgMessage);
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
} catch (SocketException e) {
// TODO: handle exception
System.out.println("exit!");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
/**
* 通过handler更新UI
*/
Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 0x1981:
chatbox.setText(chatbox.getText() + reMsg + '\n');
chatbox.setSelection(chatbox.length());
break;
}
}
};
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
disConnect();
//System.exit(0);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
menu.add(0, 1, 1, "初始化設置");
menu.add(0, 2, 2, "退出");
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
if(item.getItemId()==1){
Intent intent = new Intent(SocketmsgActivity.this,IniActivity.class);
startActivity(intent);
SocketmsgActivity.this.finish();
}else if(item.getItemId()==2){
disConnect();
SocketmsgActivity.this.finish();
android.os.Process.killProcess(android.os.Process.myPid());
System.exit(0);
}
return super.onOptionsItemSelected(item);
}
public void InitDatabase(){
if(!config.path.exists()){
config.path.mkdirs();
Log.i("LogDemo", "mkdir");
}
if(!config.f.exists()){
try{
config.f.createNewFile();
Log.i("LogDemo", "create a new database file");
}catch(IOException e){
Log.i("LogDemo",e.toString());
}
}
try {
if(tabIsExist("config")==false){
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
db.execSQL("create table config(_id integer primary key autoincrement," +
"ip varchar(128),port varchar(10),name varchar(32))");
Log.i("LogDemo", "create a database");
db.close();
}
} catch (Exception e) {
// TODO: handle exception
Log.i("LogDemo",e.toString());
}
}
/**
* check the database is already exist
* @param tabName
* @return
*/
public boolean tabIsExist(String tabName){
boolean result = false;
if(tabName == null){
return false;
}
Cursor cursor = null;
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
try {
String sql = "select count(*) as c from sqlite_master where type ='table' " +
"and name ='"+tabName.trim()+"' ";
cursor = db.rawQuery(sql, null);
if(cursor.moveToNext()){
int count = cursor.getInt(0);
if(count>0){
result = true;
}
}
} catch (Exception e) {
// TODO: handle exception
}
cursor.close();
db.close();
return result;
}
}
2.初始化IP和端口Activity， IniActivity.java
public class IniActivity extends Activity{
private EditText ip,port;
private Button nextButton;
private String getip,getport;
private ProgressDialog progressDialog;
private InetSocketAddress isa = null;
private SQLiteDatabase db;
private String ipstring=null,portString=null;
private int row=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.config);
ip = (EditText)findViewById(R.id.ip);
port = (EditText)findViewById(R.id.port);
nextButton = (Button)findViewById(R.id.next);
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
try {
Cursor cursor = db.query("config", new String[]{"ip","port"},null,null, null, null, null);
while(cursor.moveToNext()){
ipstring = cursor.getString(cursor.getColumnIndex("ip"));
portString = cursor.getString(cursor.getColumnIndex("port"));
row++;
}
ip.setText(ipstring);
port.setText(portString);
cursor.close();
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.toString());
}
db.close();
nextButton.setOnClickListener(new nextButtonListenner());
}
class nextButtonListenner implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
getip = ip.getText().toString().trim();
getport = port.getText().toString().trim();
if(getip=="" || getip==null || getip.equals("")){
Toast.makeText(IniActivity.this, "請輸入IP", Toast.LENGTH_SHORT).show();
ip.setFocusable(true);
}else if(getport=="" || getport==null || getport.equals("")){
Toast.makeText(IniActivity.this, "請輸入端口", Toast.LENGTH_SHORT).show();
port.setFocusable(true);
}else{
//progressDialog = ProgressDialog.show(IniActivity.this, "", "請稍後...", true, false);
//new Thread() {
//@Override
//public void run() {
try {
Socket s = new Socket();
isa = new InetSocketAddress(getip,Integer.parseInt(getport));
s.connect(isa,5000);
//showDialog("連接成功",IniActivity.this);
try {
//生成ContentValues对象
ContentValues values = new ContentValues();
//想该对象当中插入键值对，其中键是列名，值是希望插入到这一列的值，值必须和数据库当中的数据类型一致
values.put("ip", getip);
values.put("port",getport);
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
if(row==0){
db.insert("config", null, values);
}else{
db.update("config", values ,null,null);
}
Toast.makeText(IniActivity.this, "連接成功", Toast.LENGTH_SHORT);
s.close();
Intent intent = new Intent(IniActivity.this,IniuserActivity.class);
startActivity(intent);
IniActivity.this.finish();
db.close();
} catch (Exception e) {
// TODO: handle exception
showDialog("設置失敗，數據庫不可用",IniActivity.this);
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
showDialog("連接失敗，IP或者端口不可用",IniActivity.this);
}catch (SocketTimeoutExceptione) {
System.out.println("連接超時，服務器未開啟或IP錯誤");
showDialog("連接超時，服務器未開啟或IP錯誤",IniActivity.this);
e.printStackTrace();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
showDialog("連接失敗，IP或者端口不可用",IniActivity.this);
}
//progressDialog.dismiss();
//finish();
//}
//}.start();
}
}
}
/**
* define a dialog for show the message
* @param mess
* @param activity
*/
public void showDialog(String mess,Activity activity){
new AlertDialog.Builder(activity).setTitle("信息")
.setMessage(mess)
.setNegativeButton("確定",new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
}
})
.show();
}
}
3.初始化用户名称Activity， IniuserActivity.java
public class IniuserActivity extends Activity{
private EditText name;
private Button ok;
private SQLiteDatabase db;
private String nameString;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.configuser);
name = (EditText)findViewById(R.id.name);
ok = (Button)findViewById(R.id.ok);
ok.setOnClickListener(new okButtonListenner());
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
try {
Cursor cursor = db.query("config", new String[]{"name"},null,null, null, null, null);
while(cursor.moveToNext()){
nameString = cursor.getString(cursor.getColumnIndex("name"));
}
name.setText(nameString);
cursor.close();
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.toString());
}
db.close();
}
class okButtonListenner implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String getname = name.getText().toString().trim();
if(getname==""){
Toast.makeText(IniuserActivity.this, "請輸入您的稱呢", Toast.LENGTH_SHORT).show();
name.setFocusable(true);
}else{
try {
//生成ContentValues对象
ContentValues values = new ContentValues();
//想该对象当中插入键值对，其中键是列名，值是希望插入到这一列的值，值必须和数据库当中的数据类型一致
values.put("name", getname);
db = SQLiteDatabase.openOrCreateDatabase(config.f, null);
db.update("config",values,null,null);
Toast.makeText(IniuserActivity.this, "設置完成", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(IniuserActivity.this,SocketmsgActivity.class);
startActivity(intent);
IniuserActivity.this.finish();
db.close();
} catch (Exception e) {
// TODO: handle exception
showDialog("設置失敗，數據庫不可用",IniuserActivity.this);
}
}
}
}
/**
* define a dialog for show the message
* @param mess
* @param activity
*/
public void showDialog(String mess,Activity activity){
new AlertDialog.Builder(activity).setTitle("信息")
.setMessage(mess)
.setNegativeButton("確定",new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
}
})
.show();
}
}
4.config.java
public class config{
public static String SDCARD = android.os.Environment.getExternalStorageDirectory().getAbsolutePath();
public static File path = new File(SDCARD+"/RunChatDatabase/"); //数据库文件目录
public static File f = new File(SDCARD+"/RunChatDatabase/config.db"); //数据库文件
}
布局文件：
1.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">
<EditText android:id="@+id/chatbox" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:layout_weight="1">
</EditText>
<EditText android:id="@+id/chattxt" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:gravity="top"
android:hint="你想和对方说点什么？">
</EditText>
<Button android:id="@+id/chatOk" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="Send"
android:textSize="@dimen/btn1">
</Button>
</LinearLayout>
2.config.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">
<EditText android:id="@+id/chatbox" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:layout_weight="1">
</EditText>
<EditText android:id="@+id/chattxt" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:gravity="top"
android:hint="你想和对方说点什么？">
</EditText>
<Button android:id="@+id/chatOk" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="Send"
android:textSize="@dimen/btn1">
</Button>
</LinearLayout>
3.configuer.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">
<EditText android:id="@+id/chatbox" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:layout_weight="1">
</EditText>
<EditText android:id="@+id/chattxt" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:gravity="top"
android:hint="你想和对方说点什么？">
</EditText>
<Button android:id="@+id/chatOk" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="Send"
android:textSize="@dimen/btn1">
</Button>
</LinearLayout>
style文件：dimens.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<dimen name="h3">30dip</dimen>
<dimen name="h2">40dip</dimen>
<dimen name="btn1">30dip</dimen>
<dimen name="et1">25dip</dimen>
</resources>
最后是服务器文件：Server.java
import java.io.*;
import java.net.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;
import javax.sound.sampled.Port;
import javax.swing.JOptionPane;
public class Server {
ServerSocket ss = null;
private String getnameString=null;
boolean started = false;
List<Client> clients = new ArrayList<Client>();
List<Info> infos = new ArrayList<Info>();
public static void main(String[] args) {
String inputport = JOptionPane.showInputDialog("請輸入該服務器使用的端口:");
int port = Integer.parseInt(inputport);
new Server().start(port);
}
public void start(int port) {
try {
ss = new ServerSocket(port);
System.out.println("服務器啟動");
started = true;
} catch (BindException e) {
System.out.println(" 端口已经被占用");
System.exit(0);
}
catch (IOException e) {
e.printStackTrace();
}
try {
while (started) {
Socket s = ss.accept();
Client c = new Client (s);
System.out.println("a client is connected");
new Thread(c).start();
clients.add(c);
}
} catch (IOException e) {
e.printStackTrace();
}
finally {
try {
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public List<Client> getClient(){
return clients;
}
class Client implements Runnable {
private String chatKey="SLEEKNETGEOCK4stsjeS";
private Socket s = null;
private DataInputStream dis = null;
private DataOutputStream dos = null;
private boolean bConnected = false;
private String sendmsg=null;
Client (Socket s) {
this.s = s;
try {
dis = new DataInputStream (s.getInputStream());
dos = new DataOutputStream (s.getOutputStream());
bConnected = true;
} catch(IOException e) {
e.printStackTrace();
}
}
public void send (String str) {
try {
//System.out.println(s);
dos.writeUTF(str+"");
dos.flush();
} catch(IOException e) {
clients.remove(this);
System.out.println("对方已经退出了");
}
}
public void run() {
try {
while (bConnected) {
String str = dis.readUTF();
DateFormat df = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String date = "["+df.format(new Date())+"]";
if(str.startsWith(chatKey+"online:")){
Info info = new Info();
getnameString = str.substring(27);
info.setName(getnameString);
infos.add(info);
for (int i=0; i<clients.size(); i++) {
Client c = clients.get(i);
c.send(getnameString+" on line."+date);
}
System.out.println(getnameString+" on line."+date);
}else if(str.startsWith(chatKey+"offline:")){
getnameString = str.substring(28);
clients.remove(this);
for (int i=0; i<clients.size(); i++) {
Client c = clients.get(i);
c.send(getnameString+" off line."+date);
}
System.out.println(getnameString+" off line."+date);
}
else{
int charend = str.indexOf("end;");
String chatString = str.substring(charend+4);
String chatName = str.substring(25, charend);
sendmsg=chatName+date+"\n"+chatString;
for (int i=0; i<clients.size(); i++) {
Client c = clients.get(i);
c.send(sendmsg);
}
System.out.println(sendmsg);
}
}
} catch (SocketException e) {
System.out.println("client is closed!");
clients.remove(this);
} catch (EOFException e) {
System.out.println("client is closed!");
clients.remove(this);
}
catch (IOException e) {
e.printStackTrace();
}
finally {
try {
if (dis != null) dis.close();
if (dos != null) dos.close();
if (s != null) s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class Info{
private String info_name = null;
public Info(){
}
public void setName(String name){
info_name = name;
}
public String getName(){
return info_name;
}
}
}
以上只是一个粗略的聊天室功能，如果要实现私聊，还需要保存该Socket关联的客户信息。一个客户端可以将信息发送另一个指定客户端。
