Android与JavaIO实现简单Echo服务器与客户端_android程序echo

温习旧知识，巩固基础，同时还能有新的收货。

古人云：温故而知新，可以为师矣。

那就分享出来一起学习吧。

服务端，纯Java实现：

public class EchoServer {
 
    public static void main(String args[]) {
        try {
            ServerSocket serverSocket = new ServerSocket(8999);
            while (true) {  //直接在主线程做了，不另起线程了
                Socket socket = serverSocket.accept();
                System.out.println("connected from:" + socket.getInetAddress());
                new SocketThread(socket).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    private static class SocketThread extends Thread {
        private Socket mSocket;
 
        public SocketThread(Socket socket) {
            this.mSocket = socket;
        }
 
        @Override
        public void run() {
            BufferedReader br = null;
            PrintWriter pw = null;
            try {
                br = new BufferedReader(new InputStreamReader(mSocket.getInputStream()));
                pw = new PrintWriter(new OutputStreamWriter(mSocket.getOutputStream()));
                String line;
                while (true) {
                    line = br.readLine();
                    System.out.println("received:" + line + " from:" + mSocket.getInetAddress());
                    String result = "response: " + line + "\n"; //我们用的都是readLine方法读取，所以加入换行符，代表结尾
                    pw.print(result);
                    pw.flush();
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (br != null) {
                    try {
                        br.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (pw != null) {
                    pw.close();
                }
                if (mSocket != null && !mSocket.isClosed()) {
                    try {
                        mSocket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}

Android客户端：

public class MainActivity extends AppCompatActivity {
    private EditText mIpEt;
    private EditText mPortEt;
    private Button mConnBtn;
    private TextView mScreenTv;
    private EditText mInputEt;
    private Button mSendBtn;
 
    private SocketThread mSocketThread;
    private static Handler mMainHandler;
 
    private static final int MSG_CONNECT = 0x001;
    private static final int MSG_RECEIVE = 0x002;
 
    private static final String DATA_RECEIVE = "data_receive";
 
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        mIpEt = findViewById(R.id.main_ip_et);
        mPortEt = findViewById(R.id.main_port_et);
        mConnBtn = findViewById(R.id.main_connect_btn);
        mScreenTv = findViewById(R.id.main_screen_tv);
        mInputEt = findViewById(R.id.main_input_et);
        mSendBtn = findViewById(R.id.main_send_btn);
 
        // defalut value. Change it to your own server ip
        mIpEt.setText("192.168.1.1");
        mPortEt.setText("8999");
 
        mConnBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String ip = mIpEt.getText().toString();
                String port = mPortEt.getText().toString();
                if (TextUtils.isEmpty(ip) || TextUtils.isEmpty(port)) {
                    Toast.makeText(MainActivity.this, "ip or port is null", Toast.LENGTH_SHORT).show();
                } else {
                    connectToServer(ip, Integer.valueOf(port));
                }
            }
        });
 
        mSendBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data = mInputEt.getText().toString();
                if (!TextUtils.isEmpty(data)) {
                    mSocketThread.sendMsgToServer(data + "\n"); //我们用的都是readLine方法读取，所以加入换行符，代表结尾
                }
            }
        });
 
        // TODO handler may cause memory leaks
        mMainHandler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                switch (msg.what) {
                    case MSG_CONNECT:
                        Toast.makeText(MainActivity.this, "Connect to Server Success", Toast.LENGTH_SHORT).show();
                        mConnBtn.setText("Connected");
                        mConnBtn.setEnabled(false);
                        break;
                    case MSG_RECEIVE:
                        Bundle data = msg.getData();
                        String dataStr = data.getString(DATA_RECEIVE);
                        CharSequence originData = mScreenTv.getText();
                        String result = originData + "\n" + dataStr;
                        mScreenTv.setText(result);
                        break;
                }
            }
        };
    }
 
 
    private void connectToServer(String ip, int port) {
        mSocketThread = new SocketThread(ip, port);
        mSocketThread.start();
    }
 

    // 程序简单，直接写静态内部类来实现了
    private static class SocketThread extends Thread {
        private Socket mSocket;
        private String mIp;
        private int mPort;
        private InputStream mInputStream;
        private BufferedReader mBufferedReader;
        private PrintWriter mPrintWriter;
 
        public SocketThread(String ip, int port) {
            this.mIp = ip;
            this.mPort = port;
        }
 
        @Override
        public void run() {
            try {
                mSocket = new Socket(mIp, mPort);
                mMainHandler.sendEmptyMessage(MSG_CONNECT);
 
                // init i/o stream
                mInputStream = mSocket.getInputStream();
                mBufferedReader = new BufferedReader(new InputStreamReader(mInputStream));
                OutputStream outputStream = mSocket.getOutputStream();
                mPrintWriter = new PrintWriter(outputStream);
 
                String line;
                while (true) {
                    line = mBufferedReader.readLine();
                    Message message = mMainHandler.obtainMessage();
                    message.what = MSG_RECEIVE;
                    Bundle data = new Bundle();
                    data.putString(DATA_RECEIVE, line);
                    message.setData(data);
                    mMainHandler.sendMessage(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (mBufferedReader != null) {
                    try {
                        mBufferedReader.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (mInputStream != null) {
                    try {
                        mInputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (mPrintWriter != null) {
                    mPrintWriter.close();
                }
                if (mSocket != null && !mSocket.isClosed()) {
                    try {
                        mSocket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
 
        public void sendMsgToServer(final String data) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    mPrintWriter.print(data);
                    mPrintWriter.flush();
                }
            }).start();
        }
    }
}

MainActivity的布局文件。

<?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"
    android:layout_margin="15dp">
 
    <EditText
        android:id="@+id/main_ip_et"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="ip address"/>
 
    <EditText
        android:id="@+id/main_port_et"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="port"
        android:inputType="number"/>
 
    <Button
        android:id="@+id/main_connect_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Connect"/>
 
    <EditText
        android:id="@+id/main_input_et"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="message to server"/>
 
    <Button
        android:id="@+id/main_send_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Send"/>
 
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="10dp">
        <TextView
            android:id="@+id/main_screen_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="received message will be shown here"/>
    </ScrollView>
 
</LinearLayout>

最后别忘了Android客户端里声明网络权限。

其他就没有什么特别要注意的点了，直接跑起来吧~

客户端运行

服务端日志