NIO例子

程序员文章站 2022-05-04 08:48:45

client向server发送questionId，server随机得到1个答案，然后把questionId和答案发送给clientAnswerServerpublic class AnswerServer { private static AtomicLong atomicLong = new AtomicLong(); public static final String[] answers = {"A","B","C","D"}; public stat.....

client向server发送questionId，server随机得到1个答案，然后把questionId和答案发送给client

AnswerServer

public class AnswerServer {

    private static AtomicLong atomicLong = new AtomicLong();

    public static final String[] answers = {"A","B","C","D"};

    public static final String RES_CONNECTION_OK = "OK";

    static Random random = new Random(3);

    private Selector selector;

    public AnswerServer(){
        try{
            this.init();
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public void init() throws Exception{
        //打开1个io多路复用器
        selector = Selector.open();

        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.configureBlocking(false);
        //绑定服务端口
        serverSocketChannel.socket().bind(new InetSocketAddress(Constant.SERVER.IP,Constant.SERVER.PORT));

        System.out.println("answer server linten port="+Constant.SERVER.PORT);

        //对于服务端来说，一定要先注册一个OP_ACCEPT事件用来响应客户端的请求连接
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

    }

    public void start() throws Exception{

        while (true) {
            this.selector.select();
            System.out.println("the coming keys="+this.selector.selectedKeys());

            Iterator<SelectionKey> iterator = this.selector.selectedKeys().iterator();

            while(iterator.hasNext()) {
                SelectionKey key = iterator.next();
                iterator.remove();
                SocketChannel socketChannel = null;
                int type = 0;
                try {
                    if (key.isAcceptable()) {
                        //这里key.channel是ServerSocketChannel
                        type = SelectionKey.OP_ACCEPT;
                        this.accept(key);
                    } else if (key.isValid() && key.isReadable()) {
                        type = SelectionKey.OP_READ;
                        socketChannel = (SocketChannel) key.channel();
                        this.read(socketChannel, key);
                    }
                }catch (Exception e) {
                    key.cancel();
                    if(socketChannel!=null){
                        socketChannel.socket().close();
                        socketChannel.close();
                    }
                    System.out.println("exception at type="+type);
                    e.printStackTrace();
                }

            }

        }
    }

    private void accept(SelectionKey key) throws Exception {
        ServerSocketChannel serverSocketChannel = (ServerSocketChannel)key.channel();
        SocketChannel socketChannel = serverSocketChannel.accept();
        socketChannel.configureBlocking(false);
        System.out.println("开始注册读时间");

        socketChannel.register(this.selector,SelectionKey.OP_READ);

        this.sayAcceptOk(socketChannel);

    }

    private void sayAcceptOk(SocketChannel socketChannel) throws Exception{
        ByteBuffer byteBuffer = ByteBuffer.wrap(AnswerServer.RES_CONNECTION_OK.getBytes());
        System.out.println("AnswerServer发送连接成功!");
        socketChannel.write(byteBuffer);
    }

    private void read(SocketChannel channel,SelectionKey key) throws Exception {
        System.out.println(atomicLong.incrementAndGet()+",开始读数据 key="+key);
        // 先得到题目

        ByteBuffer buffer = ByteBuffer.allocate(50);

        while (channel.isOpen() && channel.read(buffer) != -1) {
           
            if (buffer.position() > 0) {
                System.out.println("数据读完了-----------------------position="+buffer.position());
                break;
            }
        }
        if (buffer.position() == 0) {
            System.out.println("没有数据了-----------------------");
            return; // 如果没数据了, 则不继续后面的处理
        }

        String questionId = ByteBufferUtil.toString(buffer);
        System.out.println("========read questionId :" + questionId);

        String answer = answers[random.nextInt(4)];

        String response = "questionId="+questionId+",answerId="+answer;

        ByteBuffer responseBuffer = ByteBuffer.wrap(response.getBytes());
        channel.write(responseBuffer);

    }

    public static void main(String[] args) throws Exception{
        new AnswerServer().start();
    }

}

AnswerNIOClient

public class AnswerNIOClient implements MyRunnable {

    private Selector selector;
    SocketChannel socketChannel;
    private AtomicLong atomicLong = new AtomicLong();

    public AnswerNIOClient() throws Exception {
        this.init();
    }


    @Override
    public void init() throws Exception {
        selector = Selector.open();
        socketChannel = SocketChannel.open();
        socketChannel.configureBlocking(false);
//        System.out.println("end init method");
    }

    @Override
    public void start() throws Exception {
//        System.out.println("call start method");
        try {
            this.doConnect();
//            System.out.println("after call doConnect method");
        }catch (Exception e){
            System.out.println("连接失败!");
            e.printStackTrace();
            System.exit(-1);
        }


        while (true) {
            selector.select();
            try {

                Iterator<SelectionKey> iterator = this.selector.selectedKeys().iterator();

                while (iterator.hasNext()) {
                    SelectionKey key = iterator.next();
                    iterator.remove();

                    SocketChannel sc = (SocketChannel) key.channel();

                    System.out.println("isTrue=" + (sc==socketChannel));
                    System.out.println("socketChannel=" + socketChannel);

                    if(key.isConnectable()) {
                        if (sc.finishConnect()) {
                                System.out.println("==========finishConnect==================================");
                            sc.register(selector, SelectionKey.OP_READ);
                            this.doWrite(socketChannel);
                        } else {
                            //连接失败 进程退出
                            System.exit(1);
                        }

                    } else if (key.isValid() && key.isReadable()) {
                        this.doRead(sc, key);
                    } else if (key.isValid() && key.isWritable()) {
                        this.doWrite(sc);
                    }

                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

    private void doConnect() throws Exception {
        //通过ip和端口号连接到服务器
        boolean connected = this.socketChannel.connect(new InetSocketAddress(Constant.SERVER.IP,Constant.SERVER.PORT));
        System.out.println("doConnect="+connected);
        if(connected){
            //向多路复用器注册可读事件
            socketChannel.register(this.selector,SelectionKey.OP_READ);
        } else {
            //若连接服务器失败,则向多路复用器注册连接事件
            socketChannel.register(this.selector, SelectionKey.OP_CONNECT);
        }

    }

    private void doRead(SocketChannel socketChannel,SelectionKey key) throws Exception {
        ByteBuffer readBuffer = ByteBuffer.allocate(1024);
        socketChannel.read(readBuffer);
        String content = ByteBufferUtil.toString(readBuffer);
        System.out.println("服务器响应！ 问题及答案:"+content);

        socketChannel.register(this.selector,SelectionKey.OP_WRITE);

    }


    private void doWrite(SocketChannel socketChannel) throws Exception {
        Long questionId = getQuestionId();

        ByteBuffer byteBuffer = ByteBuffer.wrap(String.valueOf(questionId).getBytes());
        socketChannel.write(byteBuffer);
        System.out.println("AnswerNIOClient 发送查询答案！ questionId="+questionId);

        socketChannel.register(this.selector,SelectionKey.OP_READ);

    }


    private Long getQuestionId() throws Exception{
        TimeUnit.SECONDS.sleep(3);
        Long questionId = atomicLong.incrementAndGet();
        return questionId;


    }

    public static void main(String[] args) throws Exception{
        new AnswerNIOClient().start();
    }

}

AnswerBIOClient

public class AnswerBIOClient {

    Socket socket = new Socket();

    private AtomicLong atomicLong = new AtomicLong();

    private boolean isConnectionOk = false;

    public AnswerBIOClient(){

        try{
            init();
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public void init() throws Exception{
        socket.connect(new InetSocketAddress(Constant.SERVER.IP,Constant.SERVER.PORT));
        if(socket.isConnected()) {
            System.out.println("AnswerBIOClient连接成功! 服务端端口="+socket.getPort()+" 客户端端口="+socket.getLocalPort());
        }
    }

    public void start() throws Exception{
        Runnable readRunnable = ()->{
            try {
                read();
            }catch (Exception e){
                System.out.println("readRunnable exception "+e.getMessage());
                e.printStackTrace();
            }
        };

        Runnable writeRunnable = ()->{
            try {
                write();
            }catch (Exception e){
                System.out.println("readRunnable exception "+e.getMessage());
                e.printStackTrace();
            }
        };

        Thread readThread = new Thread(readRunnable,"readThread");
        Thread writeThread = new Thread(writeRunnable,"writeThread");

        readThread.start();
        writeThread.start();

    }

    private void read1() throws Exception{
        while(true) {
            //服务器返回需要加\n
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            System.out.println("等待读数据");
            String line = null;
            while((line=bufferedReader.readLine())!=null) {
                System.out.println("AnswerBIOClient read server data =" + line);
            }

        }

    }

    private void read() throws Exception{

        while(true) {
            System.out.println("等待读数据");

            byte[] bytes = new byte[512];
            int readLength = socket.getInputStream().read(bytes);
            System.out.println("readLength="+readLength);
            while (readLength!=-1) {
                String result = new String(bytes,0,readLength);
                if(!isConnectionOk){
                    isConnectionOk = result.equals(AnswerServer.RES_CONNECTION_OK);
                    System.out.println("result="+result+" isConnectionOk="+isConnectionOk+" o:"+result.equals(AnswerServer.RES_CONNECTION_OK));
                }
            }

        }

    }

    private void write() throws Exception{

        while (true) {
            if (isConnectionOk) {
                TimeUnit.SECONDS.sleep(5);
                Long questionId = atomicLong.incrementAndGet();
                System.out.println("客户端开始发送 questionId=" + questionId);
                socket.getOutputStream().write(String.valueOf(questionId).getBytes());
                socket.getOutputStream().flush();
            }
        }

    }

    public static void main(String[] args) throws Exception{

        new AnswerBIOClient().start();

    }

}

本文地址：https://blog.csdn.net/kq1983/article/details/107495341

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