<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical">

 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="horizontal">
  <!-- 定義一個(gè)文本框，它用于接收用戶(hù)的輸入 -->
  <EditText
   android:id="@+id/input"
   android:layout_width="280dp"
   android:layout_height="wrap_content" />

  <Button
   android:id="@+id/send"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:paddingLeft="8dp"
   android:text="發(fā)送" />
 </LinearLayout>
 <!-- 定義一個(gè)文本框，它用于顯示來(lái)自服務(wù)器的信息 -->
 <TextView
  android:id="@+id/show"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="#ffff"
  android:gravity="top"
  android:textColor="#f000"
  android:textSize="18sp" />
</LinearLayout>

package com.fukaimei.multithreadclient;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

 // 定義界面上的兩個(gè)文本框
 EditText input;
 TextView show;
 // 定義界面上的一個(gè)按鈕
 Button send;
 Handler handler;
 // 定義與服務(wù)器通信的子線(xiàn)程
 ClientThread clientThread;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  input = (EditText) findViewById(R.id.input);
  send = (Button) findViewById(R.id.send);
  show = (TextView) findViewById(R.id.show);
  handler = new Handler() // ②
  {
   @Override
   public void handleMessage(Message msg) {
    // 如果消息來(lái)自于子線(xiàn)程
    if (msg.what == 0x123) {
     // 將讀取的內(nèi)容追加顯示在文本框中
     show.append("\n" + msg.obj.toString());
    }
   }
  };
  clientThread = new ClientThread(handler);
  // 客戶(hù)端啟動(dòng)ClientThread線(xiàn)程創(chuàng)建網(wǎng)絡(luò)連接、讀取來(lái)自服務(wù)器的數(shù)據(jù)
  new Thread(clientThread).start(); // ①
  send.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
    try {
     // 當(dāng)用戶(hù)按下發(fā)送按鈕后，將用戶(hù)輸入的數(shù)據(jù)封裝成Message
     // 然后發(fā)送給子線(xiàn)程的Handler
     Message msg = new Message();
     msg.what = 0x234;
     msg.obj = input.getText().toString();
     clientThread.revHandler.sendMessage(msg);
     // 清空input文本框
     input.setText("");
    } catch (Exception e) {
     e.printStackTrace();
    }
   }
  });
 }
}

package com.fukaimei.multithreadclient;

import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.net.SocketTimeoutException;

public class ClientThread implements Runnable {

 private static final String TAG = "ClientThread";
 private Socket s;
 // 定義向UI線(xiàn)程發(fā)送消息的Handler對(duì)象
 private Handler handler;
 // 定義接收UI線(xiàn)程的消息的Handler對(duì)象
 public Handler revHandler;
 // 該線(xiàn)程所處理的Socket所對(duì)應(yīng)的輸入流
 BufferedReader br = null;
 OutputStream os = null;

 public ClientThread(Handler handler) {
  this.handler = handler;
 }

 public void run() {
  try {
   s = new Socket("172.xx.xx.xxx", 30000);
   br = new BufferedReader(new InputStreamReader(
     s.getInputStream()));
   os = s.getOutputStream();
   // 啟動(dòng)一條子線(xiàn)程來(lái)讀取服務(wù)器響應(yīng)的數(shù)據(jù)
   new Thread() {
    @Override
    public void run() {
     String content = null;
     // 不斷讀取Socket輸入流中的內(nèi)容
     try {
      while ((content = br.readLine()) != null) {
       // 每當(dāng)讀到來(lái)自服務(wù)器的數(shù)據(jù)之后，發(fā)送消息通知程序
       // 界面顯示該數(shù)據(jù)
       Message msg = new Message();
       msg.what = 0x123;
       msg.obj = content;
       handler.sendMessage(msg);
      }
     } catch (IOException e) {
      e.printStackTrace();
     }
    }
   }.start();
   // 為當(dāng)前線(xiàn)程初始化Looper
   Looper.prepare();
   // 創(chuàng)建revHandler對(duì)象
   revHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
     // 接收到UI線(xiàn)程中用戶(hù)輸入的數(shù)據(jù)
     if (msg.what == 0x234) {
      // 將用戶(hù)在文本框內(nèi)輸入的內(nèi)容寫(xiě)入網(wǎng)絡(luò)
      try {
       os.write((msg.obj.toString() + "\r\n")
         .getBytes("utf-8"));
      } catch (Exception e) {
       e.printStackTrace();
      }
     }
    }
   };
   // 啟動(dòng)Looper
   Looper.loop();
  } catch (SocketTimeoutException e1) {
   Log.d(TAG, "網(wǎng)絡(luò)連接超時(shí)！");
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
}

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;

public class MyServer {

 // 定義保存所有Socket的ArrayList
 public static ArrayList<Socket> socketList = new ArrayList<Socket>();

 public static void main(String[] args) throws IOException {
  ServerSocket ss = new ServerSocket(30000);
  while (true) {
   // 此行代碼會(huì)阻塞，將一直等待別人的連接
   Socket s = ss.accept();
   socketList.add(s);
   // 每當(dāng)客戶(hù)端連接后啟動(dòng)一條ServerThread線(xiàn)程為該客戶(hù)端服務(wù)
   new Thread(new ServerThread(s)).start();
  }
 }
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Iterator;

// 負(fù)責(zé)處理每條線(xiàn)程通信的線(xiàn)程類(lèi)
public class ServerThread implements Runnable {
 // 定義當(dāng)前線(xiàn)程所處理的Socket
 Socket s = null;
 // 該線(xiàn)程所處理的Socket所對(duì)應(yīng)的輸入流
 BufferedReader br = null;
 public ServerThread(Socket s) throws IOException {
  this.s = s;
  // 初始化該Socket對(duì)應(yīng)的輸入流
  br = new BufferedReader(new InputStreamReader(s.getInputStream(), "utf-8"));
 }
 @Override
 public void run() {
  String content = null;
  // 采用循環(huán)不斷從Socket中讀取客戶(hù)端發(fā)送過(guò)來(lái)的數(shù)據(jù)
  while ((content = readFromClient()) != null) {
   // 遍歷socketList中的每個(gè)Socket
   // 將讀取的內(nèi)容向每個(gè)Socket發(fā)送一次
   for (Iterator<Socket> it = MyServer.socketList.iterator(); it.hasNext();) {
    Socket s = it.next();
    try {
     OutputStream os = s.getOutputStream();
     os.write((content + "\n").getBytes("utf-8"));
    } catch (Exception e) {
     e.printStackTrace();
     // 刪除該Socket
     it.remove();
     System.out.println(MyServer.socketList);
    }
   }
  }
 }
 // 定義讀取客戶(hù)端數(shù)據(jù)的方法
 private String readFromClient() {
  try {
   return br.readLine();
  } catch (IOException e) { // 如果捕獲到異常，表明該Socket對(duì)應(yīng)的客戶(hù)端已經(jīng)關(guān)閉
   e.printStackTrace();
   // 刪除該Socket
   MyServer.socketList.remove(s);
  }
  return null;
 }
}

<!-- 授權(quán)訪(fǎng)問(wèn)互聯(lián)網(wǎng)-->
 <uses-permission android:name="android.permission.INTERNET" />