本章節(jié) 比較簡單
直接上code了
首先創(chuàng)建一個UDP class 構(gòu)造方法如下
通過newFixedThreadPool 創(chuàng)建一個線程池

public UdpSocket(Context mContent) {
        this.mContent = mContent;
        int cpuNumbers = Runtime.getRuntime().availableProcessors();
        // 根據(jù)CPU數(shù)目初始化線程池
        mThreadPool = Executors.newFixedThreadPool(cpuNumbers * POOL_SIZE);
        // 記錄創(chuàng)建對象時的時間
    }

然后
一個startUdp scoket 重要步驟

public void startUDPSocket() {
        if (client != null) return;
        try {
            client = new DatagramSocket(CLIENT_PORT);
            if (receivePacket == null) {
                // 創(chuàng)建接受數(shù)據(jù)的 packet
                receivePacket = new DatagramPacket(receiveByte, BUFFER_LENGTH);
            }
            startSocketThread();
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }

startSocketThread是一個 接收消息的子線程
內(nèi)部是一個接收消息的循環(huán)
BROADCAST_IP 是通信對方的地址

    private void startSocketThread() {
        clientThread = new Thread(new Runnable() {
            @Override
            public void run() {
                printMessage("clientThread is running...");
                receiveMessage();
            }
        });
        isThreadRunning = true;
        clientThread.start();
    }

    private void receiveMessage() {
        while (isThreadRunning) {
            try {
                if (client != null) {
                    client.receive(receivePacket);
                }
                printMessage("message success...");
            } catch (IOException e) {
                Log.e(TAG, "UDP數(shù)據(jù)包接收失敗！stopUDPSocket");
                stopUDPSocket();
                e.printStackTrace();
                return;
            }

            if (receivePacket == null || receivePacket.getLength() == 0) {
                Log.e(TAG, "無法接收UDP數(shù)據(jù)或者接收到的UDP數(shù)據(jù)為空");
                continue;
            }

            String strReceive = new String(receivePacket.getData(), 0, receivePacket.getLength());
            printMessage(" data:  " + strReceive + " from " + receivePacket.getAddress().getHostAddress() + ":" + receivePacket.getPort());

            //解析接收到的 json 信息

            // 每次接收完UDP數(shù)據(jù)后，重置長度。否則可能會導(dǎo)致下次收到數(shù)據(jù)包被截斷。
            if (receivePacket != null) {
                receivePacket.setLength(BUFFER_LENGTH);
            }
        }
    }

利用廣播 把接收到的消息打印到前臺

    public void printMessage(String s) {
        Log.d(TAG, s);
        Intent intent = new Intent();
        intent.setAction(MainActivity.REFRESH_ACTION);
        intent.putExtra("Message", s);
        mContent.sendBroadcast(intent);
    }

再然后創(chuàng)建一個發(fā)送message的方法

public void sendMessage(final byte[] message) {
        mThreadPool.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    DatagramPacket sendPacket = new DatagramPacket(message, message.length,
                            InetAddress.getByName(BROADCAST_IP), CLIENT_PORT);
                    client.send(sendPacket);

                    // 數(shù)據(jù)發(fā)送事件
                    printMessage("數(shù)據(jù)發(fā)送成功");

                } catch (UnknownHostException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        });
    }

文章所有code 地址---> github
https://github.com/hanjole/Udpscoket_demo