Java Socket实战之一 单线程通信 。 首先是写一个Server类，这个类用来监听10000端口，并从这个端口接收消息然后输出，当收到“bye”时退出。 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 MyServer { public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); Socket socket = server.accept(); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); while (true) { String msg = in.readLine(); System.out.println(msg); out.println("Server received " + msg); out.flush(); if (msg.equals("bye")) { break; } } socket.close(); } } package com.googlecode.garbagecan.test.socket.sample1; 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 MyServer { public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); Socket socket = server.accept(); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); while (true) { String msg = in.readLine(); System.out.println(msg); out.println("Server received " + msg); out.flush(); if (msg.equals("bye")) { break; } } socket.close(); } } 然后是一个Client类，这个类连接上面启动的Server类，然后接收任何用户输入，当遇到回车时发送字符串到Server上，当输入“bye”是退出。 import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.Socket; public class MyClient { public static void main(String[] args) throws Exception { Socket socket = new Socket("localhost", 10000); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while (true) { String msg = reader.readLine(); out.println(msg); out.flush(); if (msg.equals("bye")) { break; } System.out.println(in.readLine()); } socket.close(); } } import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.Socket; public class MyClient { public static void main(String[] args) throws Exception { Socket socket = new Socket("localhost", 10000); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while (true) { String msg = reader.readLine(); out.println(msg); out.flush(); if (msg.equals("bye")) { break; } System.out.println(in.readLine()); } socket.close(); } } 最后，首先运行MyServer类，然后MyClient类，然后在MyClient的控制台输入任意字符，可以看到当输入bye是server和client都会退出。 Java Socket实战之二 多线程通信 上一篇文章说到怎样写一个最简单的Java Socket通信，但是在上一篇文章中的例子有一个问题就是Server只能接受一个Client请求，当第一个Client连接后就占据了这个位置，后续Client不能再继续连接，所以需要做些改动，当Server没接受到一个Client连接请求之后，都把处理流程放到一个独立的线程里去运行，然后等待下一个Client连接请求，这样就不会阻塞Server端接收请求了。每个独立运行的程序在使用完Socket对象之后要将其关闭。具体代码如下： package com.googlecode.garbagecan.test.socket.sample2; 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 MyServer { public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); invoke(socket); } } private static void invoke(final Socket client) throws IOException { new Thread(new Runnable() { public void run() { BufferedReader in = null; PrintWriter out = null; try { in = new BufferedReader(new InputStreamReader(client.getInputStream())); out = new PrintWriter(client.getOutputStream()); while (true) { String msg = in.readLine(); System.out.println(msg); out.println("Server received " + msg); out.flush(); if (msg.equals("bye")) { break; } } } catch(IOException ex) { ex.printStackTrace(); } finally { try { in.close(); } catch (Exception e) {} try { out.close(); } catch (Exception e) {} try { client.close(); } catch (Exception e) {} } } }).start(); } } package com.googlecode.garbagecan.test.socket.sample2; 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 MyServer { public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); invoke(socket); } } private static void invoke(final Socket client) throws IOException { new Thread(new Runnable() { public void run() { BufferedReader in = null; PrintWriter out = null; try { in = new BufferedReader(new InputStreamReader(client.getInputStream())); out = new PrintWriter(client.getOutputStream()); while (true) { String msg = in.readLine(); System.out.println(msg); out.println("Server received " + msg); out.flush(); if (msg.equals("bye")) { break; } } } catch(IOException ex) { ex.printStackTrace(); } finally { try { in.close(); } catch (Exception e) {} try { out.close(); } catch (Exception e) {} try { client.close(); } catch (Exception e) {} } } }).start(); } } 下面是Client程序代码： package com.googlecode.garbagecan.test.socket.sample2; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.Socket; public class MyClient { public static void main(String[] args) throws Exception { Socket socket = new Socket("localhost", 10000); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while (true) { String msg = reader.readLine(); out.println(msg); out.flush(); if (msg.equals("bye")) { break; } System.out.println(in.readLine()); } socket.close(); } } package com.googlecode.garbagecan.test.socket.sample2; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.Socket; public class MyClient { public static void main(String[] args) throws Exception { Socket socket = new Socket("localhost", 10000); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); PrintWriter out = new PrintWriter(socket.getOutputStream()); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while (true) { String msg = reader.readLine(); out.println(msg); out.flush(); if (msg.equals("bye")) { break; } System.out.println(in.readLine()); } socket.close(); } } 测试，首先运行MyServer类，然后运行两个MyClient类，然后分别在每个MyClient的提示符下输入字符串，就可以看到Server可以分别接收处理每个Client的请求了。 Java Socket实战之三 传输对象 首先需要一个普通的对象类，由于需要序列化这个对象以便在网络上传输，所以实现java.io.Serializable接口就是必不可少的了，入下： package com.googlecode.garbagecan.test.socket.sample3; public class User implements java.io.Serializable { private static final long serialVersionUID = 1L; private String name; private String password; public User() { } public User(String name, String password) { this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } } package com.googlecode.garbagecan.test.socket.sample3; public class User implements java.io.Serializable { private static final long serialVersionUID = 1L; private String name; private String password; public User() { } public User(String name, String password) { this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } } 对于Server端的代码，代码中分别使用了ObjectInputStream和ObjectOutputStream来接收和发送socket中的InputStream和OutputStream，然后转换成Java对象，如下： [java] view plaincopyprint?package com.googlecode.garbagecan.test.socket.sample3; import java.io.*; import java.net.ServerSocket; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; public class MyServer { private final static Logger logger = Logger.getLogger(MyServer.class.getName()); public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); invoke(socket); } } private static void invoke(final Socket socket) throws IOException { new Thread(new Runnable() { public void run() { ObjectInputStream is = null; ObjectOutputStream os = null; try { is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream())); os = new ObjectOutputStream(socket.getOutputStream()); Object obj = is.readObject(); User user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); user.setName(user.getName() + "_new"); user.setPassword(user.getPassword() + "_new"); os.writeObject(user); os.flush(); } catch (IOException ex) { logger.log(Level.SEVERE, null, ex); } catch(ClassNotFoundException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { is.close(); } catch(Exception ex) {} try { os.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } }).start(); } } package com.googlecode.garbagecan.test.socket.sample3; import java.io.*; import java.net.ServerSocket; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; public class MyServer { private final static Logger logger = Logger.getLogger(MyServer.class.getName()); public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); invoke(socket); } } private static void invoke(final Socket socket) throws IOException { new Thread(new Runnable() { public void run() { ObjectInputStream is = null; ObjectOutputStream os = null; try { is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream())); os = new ObjectOutputStream(socket.getOutputStream()); Object obj = is.readObject(); User user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); user.setName(user.getName() + "_new"); user.setPassword(user.getPassword() + "_new"); os.writeObject(user); os.flush(); } catch (IOException ex) { logger.log(Level.SEVERE, null, ex); } catch(ClassNotFoundException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { is.close(); } catch(Exception ex) {} try { os.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } }).start(); } } Client也和Server端类似，同样使用ObjectOutputStream和ObjectInputStream来处理，如下： package com.googlecode.garbagecan.test.socket.sample3; import java.io.BufferedInputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; public class MyClient { private final static Logger logger = Logger.getLogger(MyClient.class.getName()); public static void main(String[] args) throws Exception { for (int i = 0; i < 100; i++) { Socket socket = null; ObjectOutputStream os = null; ObjectInputStream is = null; try { socket = new Socket("localhost", 10000); os = new ObjectOutputStream(socket.getOutputStream()); User user = new User("user_" + i, "password_" + i); os.writeObject(user); os.flush(); is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream())); Object obj = is.readObject(); if (obj != null) { user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); } } catch(IOException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { is.close(); } catch(Exception ex) {} try { os.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } } } package com.googlecode.garbagecan.test.socket.sample3; import java.io.BufferedInputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; public class MyClient { private final static Logger logger = Logger.getLogger(MyClient.class.getName()); public static void main(String[] args) throws Exception { for (int i = 0; i < 100; i++) { Socket socket = null; ObjectOutputStream os = null; ObjectInputStream is = null; try { socket = new Socket("localhost", 10000); os = new ObjectOutputStream(socket.getOutputStream()); User user = new User("user_" + i, "password_" + i); os.writeObject(user); os.flush(); is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream())); Object obj = is.readObject(); if (obj != null) { user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); } } catch(IOException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { is.close(); } catch(Exception ex) {} try { os.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } } } 最后测试上面的代码，首先运行Server类，然后运行Client类，就可以分别在Server端和Client端控制台看到接收到的User对象实例了。 Java Socket实战之四 传输压缩对象 上一篇文章说到了用Java Socket来传输对象，但是在有些情况下比如网络环境不好或者对象比较大的情况下需要把数据对象进行压缩然后在传输，此时就需要压缩这些对象流，此时就可以GZIPInputStream和GZIPOutputStream来处理一下socket的InputStream和OutputStream。 仍然需要一个实现了java.io.Serializable接口的简单Java对象 package com.googlecode.garbagecan.test.socket.sample4; public class User implements java.io.Serializable { private static final long serialVersionUID = 1L; private String name; private String password; public User() { } public User(String name, String password) { this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } } package com.googlecode.garbagecan.test.socket.sample4; public class User implements java.io.Serializable { private static final long serialVersionUID = 1L; private String name; private String password; public User() { } public User(String name, String password) { this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } } 在Server端使用，socket的InputStream首先被包装成GZIPInputStream，然后又被包装成ObjectInputStream，而socket的OutputStream首先被包装成GZIPOutputStream，然后又被包装成ObjectOutputStream，如下： package com.googlecode.garbagecan.test.socket.sample4; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.ServerSocket; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class MyServer { private final static Logger logger = Logger.getLogger(MyServer.class.getName()); public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); socket.setSoTimeout(10 * 1000); invoke(socket); } } private static void invoke(final Socket socket) throws IOException { new Thread(new Runnable() { public void run() { GZIPInputStream gzipis = null; ObjectInputStream ois = null; GZIPOutputStream gzipos = null; ObjectOutputStream oos = null; try { gzipis = new GZIPInputStream(socket.getInputStream()); ois = new ObjectInputStream(gzipis); gzipos = new GZIPOutputStream(socket.getOutputStream()); oos = new ObjectOutputStream(gzipos); Object obj = ois.readObject(); User user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); user.setName(user.getName() + "_new"); user.setPassword(user.getPassword() + "_new"); oos.writeObject(user); oos.flush(); gzipos.finish(); } catch (IOException ex) { logger.log(Level.SEVERE, null, ex); } catch(ClassNotFoundException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { ois.close(); } catch(Exception ex) {} try { oos.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } }).start(); } } package com.googlecode.garbagecan.test.socket.sample4; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.ServerSocket; import java.net.Socket; import java.util.logging.Level; import java.util.logging.Logger; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class MyServer { private final static Logger logger = Logger.getLogger(MyServer.class.getName()); public static void main(String[] args) throws IOException { ServerSocket server = new ServerSocket(10000); while (true) { Socket socket = server.accept(); socket.setSoTimeout(10 * 1000); invoke(socket); } } private static void invoke(final Socket socket) throws IOException { new Thread(new Runnable() { public void run() { GZIPInputStream gzipis = null; ObjectInputStream ois = null; GZIPOutputStream gzipos = null; ObjectOutputStream oos = null; try { gzipis = new GZIPInputStream(socket.getInputStream()); ois = new ObjectInputStream(gzipis); gzipos = new GZIPOutputStream(socket.getOutputStream()); oos = new ObjectOutputStream(gzipos); Object obj = ois.readObject(); User user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); user.setName(user.getName() + "_new"); user.setPassword(user.getPassword() + "_new"); oos.writeObject(user); oos.flush(); gzipos.finish(); } catch (IOException ex) { logger.log(Level.SEVERE, null, ex); } catch(ClassNotFoundException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { ois.close(); } catch(Exception ex) {} try { oos.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } }).start(); } } Client也和Server端类似，同样要不socket的XXXStream包装成GZIPXXXStream，然后再包装成ObjectXXXStream，如下： package com.googlecode.garbagecan.test.socket.sample4; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.InetSocketAddress; import java.net.Socket; import java.net.SocketAddress; import java.util.logging.Level; import java.util.logging.Logger; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class MyClient { private final static Logger logger = Logger.getLogger(MyClient.class.getName()); public static void main(String[] args) throws Exception { for (int i = 0; i < 10; i++) { Socket socket = null; GZIPOutputStream gzipos = null; ObjectOutputStream oos = null; GZIPInputStream gzipis = null; ObjectInputStream ois = null; try { socket = new Socket(); SocketAddress socketAddress = new InetSocketAddress("localhost", 10000); socket.connect(socketAddress, 10 * 1000); socket.setSoTimeout(10 * 1000); gzipos = new GZIPOutputStream(socket.getOutputStream()); oos = new ObjectOutputStream(gzipos); User user = new User("user_" + i, "password_" + i); oos.writeObject(user); oos.flush(); gzipos.finish(); gzipis = new GZIPInputStream(socket.getInputStream()); ois = new ObjectInputStream(gzipis); Object obj = ois.readObject(); if (obj != null) { user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); } } catch(IOException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { ois.close(); } catch(Exception ex) {} try { oos.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } } } package com.googlecode.garbagecan.test.socket.sample4; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.net.InetSocketAddress; import java.net.Socket; import java.net.SocketAddress; import java.util.logging.Level; import java.util.logging.Logger; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class MyClient { private final static Logger logger = Logger.getLogger(MyClient.class.getName()); public static void main(String[] args) throws Exception { for (int i = 0; i < 10; i++) { Socket socket = null; GZIPOutputStream gzipos = null; ObjectOutputStream oos = null; GZIPInputStream gzipis = null; ObjectInputStream ois = null; try { socket = new Socket(); SocketAddress socketAddress = new InetSocketAddress("localhost", 10000); socket.connect(socketAddress, 10 * 1000); socket.setSoTimeout(10 * 1000); gzipos = new GZIPOutputStream(socket.getOutputStream()); oos = new ObjectOutputStream(gzipos); User user = new User("user_" + i, "password_" + i); oos.writeObject(user); oos.flush(); gzipos.finish(); gzipis = new GZIPInputStream(socket.getInputStream()); ois = new ObjectInputStream(gzipis); Object obj = ois.readObject(); if (obj != null) { user = (User)obj; System.out.println("user: " + user.getName() + "/" + user.getPassword()); } } catch(IOException ex) { logger.log(Level.SEVERE, null, ex); } finally { try { ois.close(); } catch(Exception ex) {} try { oos.close(); } catch(Exception ex) {} try { socket.close(); } catch(Exception ex) {} } } } } 最后测试上面的代码，首先运行Server类，然后运行Client类，就可以分别在Server端和Client端控制台看到接收到的User对象实例了。