java NIO怎么实现简单聊天程序

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具体内容如下

服务端

功能：

1、接受客户端连接
2、发送消息
3、读取客户端消息

Server.java

public class Server {    private Selector selector;    private ByteBuffer writeBuffer = ByteBuffer.allocate(1024);    private ByteBuffer readBuffer = ByteBuffer.allocate(1024);    Msg msg = new Msg();    MsgSender msgSender = new MsgSender(msg);    public static void main(String[] args) {        Server server = new Server();        new Thread(server.msgSender).start();        server.start();    }    //初始化服务端    public Server() {        try {            this.selector = Selector.open();            ServerSocketChannel ssc = ServerSocketChannel.open();            ssc.configureBlocking(false);            ssc.bind(new InetSocketAddress(8899));            ssc.register(this.selector, SelectionKey.OP_ACCEPT);            System.out.println("服务端初始化完毕。。。。");        } catch (IOException e) {            e.printStackTrace();        }    }    //启动服务端等待selector事件    public void start() {        while (true) {            try {                int num = this.selector.select();                if (num > 0) {                    Iterator it = this.selector.selectedKeys().iterator();                    while (it.hasNext()) {                        SelectionKey key = it.next();                        it.remove();                        if (key.isValid()) {                            if (key.isAcceptable()) {                                this.accept(key);                            }                            if (key.isReadable()) {                                this.read(key);                            }                            if (key.isWritable()) {                                this.write(key);                            }                        }                    }                }            } catch (IOException e) {                e.printStackTrace();            }        }    }    //发送消息    private void write(SelectionKey key) {        SocketChannel sc = (SocketChannel) key.channel();        try {            sc.configureBlocking(false);        } catch (IOException e) {            e.printStackTrace();        }  //判断是否有消息需要发送        if(msg!=null && msg.getFlag()){            System.out.println(msg);            try {                msg.setFlag(false);                writeBuffer.clear();                writeBuffer.put(msg.getContent().getBytes());                writeBuffer.flip();                sc.write(writeBuffer);            } catch (IOException e) {                e.printStackTrace();            }        }    }    //读取客户端消息    private void read(SelectionKey key) {        SocketChannel sc = (SocketChannel) key.channel();        try {            sc.configureBlocking(false);            readBuffer.clear();            int read = sc.read(readBuffer);            if (read == -1) {                sc.close();                key.cancel();            }            readBuffer.flip();            System.out.println(new String(readBuffer.array()));        } catch (IOException e) {            e.printStackTrace();        }    }    //接受客户端连接    private void accept(SelectionKey key) {        ServerSocketChannel ssc = (ServerSocketChannel) key.channel();        try {            SocketChannel sc = ssc.accept();            System.out.println(String.format("a new client join!!!host:%s;port:%d", sc.socket().getLocalAddress(), sc.socket().getPort()));            sc.configureBlocking(false);            sc.register(this.selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);        } catch (IOException e) {            e.printStackTrace();        }    }}

Msg.java

class Msg {    private Boolean flag=false;    private String content;    public Boolean getFlag() {        return flag;    }    public void setFlag(Boolean flag) {        this.flag = flag;    }    public String getContent() {        return content;    }    public void setContent(String content) {        this.content = content;    }    @Override    public String toString() {        return "Msg{" +                "flag=" + flag +                ", content='" + content + '\'' +                '}';    }}

MsgSender.java

class MsgSender implements Runnable{    private Msg msg;    public MsgSender(Msg msg) {        this.msg = msg;    }    @Override    public void run() {        while (true) {            System.out.println("input:\n");            Scanner scanner = new Scanner(System.in);            this.msg.setContent(scanner.next());            this.msg.setFlag(true);        }    }}

客户端

采用的时BIO，简单的使用线程实现消息的读写

功能：

1、连接服务端
2、读取消息
3、发送消息

public class Client {    private SocketChannel sc;    ByteBuffer writeBuffer = ByteBuffer.allocate(1024);    ByteBuffer readBuffer = ByteBuffer.allocate(1024);    public static void main(String[] args) {        new Client();    }    public Client() {        try {            sc = SocketChannel.open();            //连接服务端            sc.connect(new InetSocketAddress(8899));            //发送消息            this.write(sc);            //读取消息            this.read(sc);        } catch (IOException e) {            e.printStackTrace();        }    }    private void read(SocketChannel sc) {        new Thread(new Runnable() {            @Override            public void run() {                while (true) {                    try {                        readBuffer.clear();                        int read = sc.read(readBuffer);                        readBuffer.flip();                        System.out.println(new String(readBuffer.array()));                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }).start();    }    private void write(SocketChannel sc) {        new Thread(new Runnable() {            @Override            public void run() {                while (true) {                    Scanner scanner = new Scanner(System.in);                    String next = scanner.next();                    writeBuffer.clear();                    writeBuffer.put(next.getBytes());                    writeBuffer.flip();                    try {                        sc.write(writeBuffer);                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }).start();    }}

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