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：
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 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<Socket> mList = new ArrayList<Socket>();
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：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="小猪简易聊天室" />
<TextView
android:id="@+id/txtshow"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<EditText
android:id="@+id/editsend"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/btnsend"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="发送"
/>
</LinearLayout>
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();
}
}
}