Java基于Socket实现简单的多线程回显服务器功能示例

package interview;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.ServerSocket;import java.net.Socket;public class EchoServer {  public static void main(String []args) throws IOException{    ServerSocket server = new ServerSocket(6789);    while(true){      Socket client = server.accept();      ClientHandler handler = new ClientHandler(client);      new Thread(handler).start();    }  }  public static class ClientHandler implements Runnable{    private Socket client;    @Override    public void run() {      InputStreamReader isr = null;      try {        isr = new InputStreamReader(client.getInputStream());        BufferedReader br = new BufferedReader(isr);        PrintWriter pw = new PrintWriter(client.getOutputStream());        String msg = br.readLine();        System.out.println("收到" + client.getInetAddress() + "发送的" + msg);        pw.println("收到了你发的" + msg);        pw.flush();      } catch (IOException e) {        e.printStackTrace();      }    }    public ClientHandler(Socket client){      this.client = client;    }  }}

package interview;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException;import java.util.Scanner;public class EchoServerClient {  public static void main(String []args) throws UnknownHostException, IOException{    Socket client = new Socket("127.0.0.1", 6789);    Scanner sc = new Scanner(System.in);    System.out.print("请输入要发送的内容：");    String msg = sc.nextLine();    sc.close();    PrintWriter pw = new PrintWriter(client.getOutputStream());    pw.println(msg);    pw.flush();    InputStreamReader isr = new InputStreamReader(client.getInputStream());    BufferedReader br = new BufferedReader(isr);    System.out.println("服务器返回：" + br.readLine());    client.close();  }}

package interview;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.CharBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.nio.charset.CharacterCodingException;import java.nio.charset.Charset;import java.nio.charset.CharsetDecoder;import java.nio.charset.CharsetEncoder;import java.util.Iterator;public class EchoServerNIO {  private static ServerSocketChannel serverChannel = null;  private static Selector selector = null;// 多路复用选择器  private static ByteBuffer buffer = null;  // 缓冲区  public static void main(String []args) throws IOException{    init();    listen();  }  static void init() throws IOException{    serverChannel = ServerSocketChannel.open();    buffer = ByteBuffer.allocate(1024);    serverChannel.socket().bind(new InetSocketAddress(6789));    serverChannel.configureBlocking(false);    selector = Selector.open();    serverChannel.register(selector, SelectionKey.OP_ACCEPT);  }  static void listen() throws IOException{    while(true){      if(selector.select(5000) != 0){        Iterator<SelectionKey> it = selector.selectedKeys().iterator();        while(it.hasNext()){          SelectionKey key = it.next();          it.remove();          handleKey(key);        }      }    }  }  static void handleKey(SelectionKey key) throws IOException{    SocketChannel channel = null;    if(key.isAcceptable()){      ServerSocketChannel serverChannel = (ServerSocketChannel)key.channel();      channel = serverChannel.accept();      channel.configureBlocking(false);      channel.register(selector, SelectionKey.OP_READ);    }else if(key.isReadable()){      channel = (SocketChannel)key.channel();      buffer.clear();      if(channel.read(buffer) > 0){        buffer.flip();        CharBuffer charBuffer = CharsetHelper.decode(buffer);        String msg = charBuffer.toString();        System.out.println("收到" + channel.getRemoteAddress() + "的消息:" + msg);        channel.write(CharsetHelper.encode(CharBuffer.wrap("received your msg:" + msg)));      }    }  }  public static class CharsetHelper{    private static final String UTF_8 = "UTF-8";    private static CharsetEncoder encoder = Charset.forName(UTF_8).newEncoder();    private static CharsetDecoder decoder = Charset.forName(UTF_8).newDecoder();    private CharsetHelper() {    }    public static ByteBuffer encode(CharBuffer in) throws CharacterCodingException{      return encoder.encode(in);    }    public static CharBuffer decode(ByteBuffer in) throws CharacterCodingException{      return decoder.decode(in);    }  }}