幾種java網絡編程服務器端的代碼

1.最開始的用io實現的

import java.io.*;
import java.net.*;
public class EchoServer{
 private int port = 8000;
 private ServerSocket serverSocket;
 public EchoServer() throws IOException{
  serverSocket = new ServerSocket(port);
  System.out.println("服務器啓動");
 }
 public String echo(String msg){
  return "echo:" + msg;
 }
 private PrintWriter getWriter(Socket socket)throws IOException{
  OutputStream socketOut = socket.getOutputStream();
  return new PrintWriter(socketOut,true);
 }
 private BufferedReader getReader(Socket socket)throws IOException{
  InputStream socketIn = socket.getInputStream();
  return new BufferedReader(new InputStreamReader(socketIn));
 }
 
 public void service(){
  while(true){
   Socket socket = null;
   try{
    socket = serverSocket.accept();
    System.out.println("New connection accepted" + socket.getInetAddress() +":" + socket.getPort());
    BufferedReader br = getReader(socket);
    PrintWriter pw = getWriter(socket);
    String msg = null;
    while((msg = br.readLine())!= null){
     System.out.println(msg);
     pw.println(echo(msg));
     if(msg.equals("bye")){
      break;
     }
    }
   }catch(IOException e){
    e.printStackTrace();
   }finally{
    try{
     if(socket != null)
      socket.close();
      
    }catch(IOException e){
     e.printStackTrace();
    }
   }
  }
 }
 public static void main(String[] args) throws IOException{
  new EchoServer().service();
 }
}

2.服務端用線程池，書上還有個本身實現線程池的，能夠看看

mport java.io.*;
import java.net.*;
import java.util.concurrent.*;
public class EchoServer3{
 private int port = 8000;
 private ServerSocket serverSocket;
 private ExecutorService executorService;
 private final int POOL_SIZE = 4;
 public EchoServer3() throws IOException{
  serverSocket = new ServerSocket(port);
  //建立線程池
  executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()*POOL_SIZE);
  System.out.println("服務器啓動");
 }
 public void service(){
  while(true){
   Socket socket = null;
   try{
    socket = serverSocket.accept();
    executorService.execute(new Handler(socket));//把與客戶通訊的任務交給線程池
   }catch(IOException e){
    e.printStackTrace();
   }
  }
 }
 public static void main(String[] args)throws Exception{
  new EchoServer3().service();
 }
}

class Handler implements Runnable{
 private SocketChannel socketChannel;
 public Handler(SocketChannel socketChannel){
  this.socketChannel = socketChannel;
 }
 public void run(){
  handle(socketChannel);
 }
 private PrintWriter getWriter(Socket socket) throws IOException{
  OutputStream socketOut = socket.getOutputStream();
  return new PrintWriter(socketOut,true);
 }
 private BufferedReader getReader(Socket socket)throws IOException{
  return new BufferedReader(new InputStreamReader(socket.getInputStream()));
 }
 public String echo(String msg){
  return "echo:" + msg;
 }
 public void handle(SocketChannel socketChannel){
  try{
   Socket socket = socketChannel.socket();
   System.out.println("接收到客戶鏈接,來自:" + socket.getInetAddress() + ":" + socket.getPort());
   BufferedReader br = getReader(socket);
   PrintWriter pw = getWriter(socket);
   String msg = null;
   while((msg = br.readLine()) != null){
    System.out.println(msg);
    pw.println(echo(msg));
    if(msg.equals("bye"))
     break;
   }
  }catch(IOException e){
   e.printStackTrace();
  }finally{
   try{
    if(socketChannel != null)
     socketChannel.close();
   }catch(IOException e){e.printStackTrace();}
  }
 }
}

3用通道了

import java.io.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
public class EchoServer{
 private int port = 8000;
 private ServerSocketChannel serverSocketChannel = null;
 private ExecutorService executorService;
 private static final int POOL_MULTIPLE = 4;
 public EchoServer() throws IOException{
  executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()*POOL_MULTIPLE);
  //建立一個ServerSocketChannel對象
  serverSocketChannel = ServerSocketChannel.open();
  serverSocketChannel.socket().setReuseAddress(true);
  serverSocketChannel.socket().bind(new InetSocketAddress(port));
  System.out.println("服務器啓動");
  
 }
 public void service(){
  while(true){
   SocketChannel socketChannel = null;
   try{
    socketChannel = serverSocketChannel.accept();
    executorService.execute(new Handler(socketChannel));
   }catch(IOException e){
    e.printStackTrace();
   }
  }
 }
 public static void main(String[] args)throws Exception{
  new EchoServer().service();
 }
}

Handler類同上

4.以上都是同步通訊方式，接下來這個是異步通訊方式了，書上還有個同步和異步一塊兒用的，在這不例出來了。

import java.io.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
public class EchoServer3{
 private Selector selector;
 private int port  = 8000;
 private ServerSocketChannel serverSocketChannel = null;
 private Charset charset = Charset.forName("GBK");
 public EchoServer3() throws IOException{
  selector = Selector.open();
  //executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() * POOL_MULTIPLE);
  //建立一個ServerSocketChannel對象
  serverSocketChannel = ServerSocketChannel.open();
  //使得在同一個主機上關閉了服務器程序，緊接着再啓動該服務器程序時，能夠順利綁定相同的端口
  serverSocketChannel.socket().setReuseAddress(true);
  serverSocketChannel.configureBlocking(false);
  serverSocketChannel.socket().bind(new InetSocketAddress(port));
  System.out.println("服務器啓動");
  
 }
 public void service()throws IOException{
  serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);
  while(selector.select() > 0){
   Set readyKeys = selector.selectedKeys();
   Iterator it = readyKeys.iterator();
   while(it.hasNext()){
    SelectionKey key = null;
    try{
     key = (SelectionKey)it.next();
     it.remove();
     if(key.isAcceptable()){
      ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
      SocketChannel socketChannel = (SocketChannel)ssc.accept();
      System.out.println("接收到客戶鏈接，來自："+ socketChannel.socket().getInetAddress() + ":"
       + socketChannel.socket().getPort());
      socketChannel.configureBlocking(false);
      ByteBuffer buffer = ByteBuffer.allocate(1024);
      socketChannel.register(selector,SelectionKey.OP_READ|SelectionKey.OP_WRITE,buffer);
     }
     if(key.isReadable()){
      receive(key);
     }
     if(key.isWritable()){
      send(key);
     }
    }catch(IOException e){
     e.printStackTrace();
     try{
      if(key != null){
       key.cancel();
       key.channel().close();
      }
     }catch(Exception ex){e.printStackTrace();}
    }
   }
  }
 }
 public void send(SelectionKey key)throws IOException{
  ByteBuffer buffer = (ByteBuffer)key.attachment();
  SocketChannel socketChannel = (SocketChannel)key.channel();
  buffer.flip();
  String data = decode(buffer);
  if(data.indexOf("\r\n") == -1) return ;
  String outputData = data.substring(0,data.indexOf("\n")+1);
  System.out.print(outputData);
  //ByteBuffer outputBuffer = data;
  ByteBuffer outputReader = encode("ehco:" + outputData);
  while(outputReader.hasRemaining())
   socketChannel.write(outputReader);
   
  ByteBuffer temp = encode(outputData);
  buffer.position(temp.limit());
  buffer.compact();
  if(outputData.equals("bye\r\n")){
   key.cancel();
   socketChannel.close();
   System.out.println("關閉與客戶的鏈接");
  }
  
   
  
  
 }
 
 public void receive(SelectionKey key) throws IOException{
  //得到與SelectionKey關聯的附件
  ByteBuffer buffer =(ByteBuffer)key.attachment();
  //得到與SelectionKey關聯的SocketChannel
  SocketChannel socketChannel = (SocketChannel)key.channel();
  //建立一個ByteBuffer,用於存放讀到的數據
  ByteBuffer readBuff = ByteBuffer.allocate(32);
  socketChannel.read(readBuff);
  readBuff.flip();
  
  buffer.limit(buffer.capacity());
  buffer.put(readBuff);
  
 }
 
 public String decode(ByteBuffer buffer){
  CharBuffer charBuffer = charset.decode(buffer);
  return charBuffer.toString();
 }
 public ByteBuffer encode(String str){
  return charset.encode(str);
 }
 public static void main(String[] args) throws Exception{
  new EchoServer3().service();
 } 
 
}