java 通信

UDP

package com.le;

import org.junit.Test;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

/**
 * <pre>
 * <b>类描述:</b> java UDP 实现
 * <b>作者:</b> zhanglei29
 * <b>创建日期:</b> 2019/4/9 16:33
 * </pre>
 */
public class UDP {

    /**
     * java -> UDP 发送报文数据
     */
    @Test
    public void send() {
        try {
            String sendStr = "使用UDP发送数据报文";
            DatagramSocket socket = new DatagramSocket();
            DatagramPacket packet = new DatagramPacket(sendStr.getBytes(), sendStr.getBytes().length, InetAddress.getByName("127.0.0.1"), 6666);
            socket.send(packet);
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * java -> UDP 接收报文
     */
    @Test
    public void receive() {
        try {
            DatagramSocket socket = new DatagramSocket(6666);
            DatagramPacket packet = new DatagramPacket(new byte[1024], 1024);
            socket.receive(packet);
            byte[] arr = packet.getData();
            int len = packet.getLength();
            String ip = packet.getAddress().getHostAddress();
            System.out.println(ip + ":" + new String(arr, 0, len));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

TCP

package com.le;

import org.junit.Test;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * <pre>
 * <b>类描述:</b> java TCP 接收和发送报文
 * <b>作者:</b> zhanglei29
 * <b>创建日期:</b> 2019/4/9 16:52
 * </pre>
 */
public class TCP {

    /**
     * java -> TCP 接收报文数据
     */
    @Test
    public void client() {
        try {
            Socket socket = new Socket("127.0.0.1", 5555);
            InputStream is = socket.getInputStream();
            OutputStream os = socket.getOutputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            PrintStream ps = new PrintStream(os);

            System.out.println(br.readLine());
            ps.println("客户端 回传数据 111111111");
            System.out.println(br.readLine());
            ps.println("客户端 回传数据 222222222");
            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * java -> TCP 发送报文数据
     */
    @Test
    public void server(){
        try {
            ServerSocket server = new ServerSocket(5555);
            Socket socket = server.accept();
            InputStream is = socket.getInputStream();
            OutputStream os = socket.getOutputStream();

            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            PrintStream ps = new PrintStream(os);

            ps.println("服务端 发送数据 111111111111");
            System.out.println(br.readLine());
            ps.println("服务端 发送数据 222222222222");
            System.out.println(br.readLine());
            server.close();
            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

NIO

　　Server

package com.le;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

/**
 * <pre>
 * <b>类描述:</b>
 * <b>作者:</b> zhanglei29
 * <b>创建日期:</b> 2019/4/8 17:53
 * </pre>
 */
public class NIOServer {

    /*标识数字*/
    private int flag = 0;
    /*缓冲区大小*/
    private int BLOCK = 4096;
    /*接受数据缓冲区*/
    private ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);
    /*发送数据缓冲区*/
    private ByteBuffer receivebuffer = ByteBuffer.allocate(BLOCK);
    private Selector selector;

    public NIOServer(int port) throws IOException {
        // 打开服务器套接字通道
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        // 服务器配置为非阻塞
        serverSocketChannel.configureBlocking(false);
        // 检索与此通道关联的服务器套接字
        ServerSocket serverSocket = serverSocketChannel.socket();
        // 进行服务的绑定
        serverSocket.bind(new InetSocketAddress(port));
        // 通过open()方法找到Selector
        selector = Selector.open();
        // 注册到selector，等待连接
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        System.out.println("Server Start----8888:");
    }

    // 监听
    private void listen() throws IOException {
        while (true) {
            // 选择一组键，并且相应的通道已经打开
            selector.select();
            // 返回此选择器的已选择键集。
            Set<SelectionKey> selectionKeys = selector.selectedKeys();
            Iterator<SelectionKey> iterator = selectionKeys.iterator();
            while (iterator.hasNext()) {
                SelectionKey selectionKey = iterator.next();
                iterator.remove();
                handleKey(selectionKey);
            }
        }
    }

    // 处理请求
    private void handleKey(SelectionKey selectionKey) throws IOException {
        // 接受请求
        ServerSocketChannel server = null;
        SocketChannel client = null;
        String receiveText;
        String sendText;
        int count = 0;
        // 测试此键的通道是否已准备好接受新的套接字连接。
        if (selectionKey.isAcceptable()) {
            System.out.println("isAcceptable");
            // 返回为之创建此键的通道。
            server = (ServerSocketChannel) selectionKey.channel();
            // 接受到此通道套接字的连接。
            // 此方法返回的套接字通道（如果有）将处于阻塞模式。
            client = server.accept();
            // 配置为非阻塞
            client.configureBlocking(false);
            // 注册到selector，等待连接
            client.register(selector, SelectionKey.OP_READ);
        } else if (selectionKey.isReadable()) {
            System.out.println("isReadable");
            // 返回为之创建此键的通道。
            client = (SocketChannel) selectionKey.channel();
            //将缓冲区清空以备下次读取
            receivebuffer.clear();
            //读取服务器发送来的数据到缓冲区中
            count = client.read(receivebuffer);
            if (count > 0) {
                receiveText = new String(receivebuffer.array(), 0, count);
                System.out.println("服务器端接受客户端数据--:" + receiveText);
                client.register(selector, SelectionKey.OP_WRITE);
            }
        } else if (selectionKey.isWritable()) {
            System.out.println("isWritable");
            //将缓冲区清空以备下次写入
            sendbuffer.clear();
            // 返回为之创建此键的通道。
            client = (SocketChannel) selectionKey.channel();
            sendText = "message from server--" + flag++;
            //向缓冲区中输入数据
            sendbuffer.put(sendText.getBytes());
            //将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
            sendbuffer.flip();
            //输出到通道
            client.write(sendbuffer);
            System.out.println("服务器端向客户端发送数据--：" + sendText);
            client.register(selector, SelectionKey.OP_READ);
        }
    }

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        int port = 8888;
        NIOServer server = new NIOServer(port);
        server.listen();
    }
}

Client

package com.le;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

/**
 * <pre>
 * <b>类描述:</b>
 * <b>作者:</b> zhanglei29
 * <b>创建日期:</b> 2019/4/8 17:57
 * </pre>
 */
public class NIOClient {

    /*标识数字*/
    private static int flag = 0;
    /*缓冲区大小*/
    private static int BLOCK = 4096;
    /*接受数据缓冲区*/
    private static ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);
    /*发送数据缓冲区*/
    private static ByteBuffer receivebuffer = ByteBuffer.allocate(BLOCK);
    /*服务器端地址*/
    private final static InetSocketAddress SERVER_ADDRESS = new InetSocketAddress(
            "localhost", 8888);

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        // 打开socket通道
        SocketChannel socketChannel = SocketChannel.open();
        // 设置为非阻塞方式
        socketChannel.configureBlocking(false);
        // 打开选择器
        Selector selector = Selector.open();
        // 注册连接服务端socket动作
        socketChannel.register(selector, SelectionKey.OP_CONNECT);
        // 连接
        socketChannel.connect(SERVER_ADDRESS);
        // 分配缓冲区大小内存

        Set<SelectionKey> selectionKeys;
        Iterator<SelectionKey> iterator;
        SelectionKey selectionKey;
        SocketChannel client;
        String receiveText;
        String sendText;
        int count=0;

        while (true) {
            //选择一组键，其相应的通道已为 I/O 操作准备就绪。
            //此方法执行处于阻塞模式的选择操作。
            selector.select();
            //返回此选择器的已选择键集。
            selectionKeys = selector.selectedKeys();
            //System.out.println(selectionKeys.size());
            iterator = selectionKeys.iterator();
            while (iterator.hasNext()) {
                selectionKey = iterator.next();
                if (selectionKey.isConnectable()) {
                    System.out.println("client connect");
                    client = (SocketChannel) selectionKey.channel();
                    // 判断此通道上是否正在进行连接操作。
                    // 完成套接字通道的连接过程。
                    if (client.isConnectionPending()) {
                        client.finishConnect();
                        System.out.println("完成连接!");
                        sendbuffer.clear();
                        sendbuffer.put("Hello,Server".getBytes());
                        sendbuffer.flip();
                        client.write(sendbuffer);
                    }
                    client.register(selector, SelectionKey.OP_READ);
                } else if (selectionKey.isReadable()) {
                    client = (SocketChannel) selectionKey.channel();
                    //将缓冲区清空以备下次读取
                    receivebuffer.clear();
                    //读取服务器发送来的数据到缓冲区中
                    count=client.read(receivebuffer);
                    if(count>0){
                        receiveText = new String( receivebuffer.array(),0,count);
                        System.out.println("客户端接受服务器端数据--:"+receiveText);
                        client.register(selector, SelectionKey.OP_WRITE);
                    }

                } else if (selectionKey.isWritable()) {
                    sendbuffer.clear();
                    client = (SocketChannel) selectionKey.channel();
                    sendText = "message from client--" + (flag++);
                    sendbuffer.put(sendText.getBytes());
                    //将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
                    sendbuffer.flip();
                    client.write(sendbuffer);
                    System.out.println("客户端向服务器端发送数据--："+sendText);
                    client.register(selector, SelectionKey.OP_READ);
                }
            }
            selectionKeys.clear();
        }
    }
}