1、查看本机的IP地址和网络相关概念
config查看本机的IP地址
ping命令测试网络是否通畅
网络是连接在一起共享数据和资源的计算机
按照覆盖范围可以分为：局域网、城域网、广域网
ping 127.0.0.1检查TCP/IP协议安装是否正确
2、基于TCP协议的网络编程
①建立连接
②打开socket关联的输入/输出流
③从流中读取信息
④关闭流和socket
注意点：
1、先写服务器，再写客户端
2、在客户端输出部分要加socket.shutdownOutput()（相当于告诉服务器我说的话说完了），若用字符流写，需要在socket.shutdownOutput()前面加上flash方法，清空缓存
3、本机localhost
4、端口号不低于1024
三、实例
1、客户端发送的请求为String字符串
package demo1; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; /* * 服务器 */ public class LoginServece { public static void main(String[] args) throws Exception { //建立连接 ServerSocket serverSocket= new ServerSocket(8000); Socket socket =serverSocket.accept(); //打开输入流 InputStream is=socket.getInputStream(); //读 BufferedReader br = new BufferedReader(new InputStreamReader(is)); String info=null; while((info=br.readLine())!=null) { System.out.println("我是服务器，客户端说："+info); } // 给回应 String reply ="我是服务器，欢迎登陆"; OutputStream os=socket.getOutputStream(); os.write(reply.getBytes()); //关闭资源 os.close(); br.close(); is.close(); socket.close(); } }
package demo1; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.Socket; import java.net.UnknownHostException; /* * 客户端 */ public class LoginClient { public static void main(String[] args) throws Exception, IOException { Socket socket = new Socket("localhost", 8000); // 发送请求 OutputStream os = socket.getOutputStream(); String info = "姓名：jim 密码12345"; os.write(info.getBytes()); socket.shutdownOutput(); // 读回应 InputStream is = socket.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(is)); String replu = null; while ((replu = br.readLine()) != null) { System.out.println("我是客户端，服务器说：" + replu); } br.close(); is.close(); os.close(); socket.close(); } }
2、客户端传出的是一个对象的情况
需要将对象序列化，注意要实现Serializable接口
package demo2; import java.io.Serializable; public class User implements Serializable{ private String name; private String psd; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPsd() { return psd; } public void setPsd(String psd) { this.psd = psd; } public User() { super(); // TODO Auto-generated constructor stub } public User(String name, String psd) { super(); this.name = name; this.psd = psd; } @Override public String toString() { return "用户名："+this.getName()+"\t"+"密码："+this.getPsd(); } }
package demo2; import java.io.InputStream; import java.io.ObjectInputStream; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; /* * 服务器 */ public class LoginServece { public static void main(String[] args) throws Exception { //建立连接 ServerSocket serverSocket= new ServerSocket(8000); Socket socket =serverSocket.accept(); //打开输入流 InputStream is=socket.getInputStream(); //读 ObjectInputStream ois = new ObjectInputStream(is); User user=(User) ois.readObject(); System.out.println(user); // 给回应 OutputStream os=socket.getOutputStream(); String reply ="我是服务器，欢迎登陆"; os.write(reply.getBytes()); //关闭资源 os.close(); ois.close(); is.close(); socket.close(); } }
package demo2; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.net.Socket; /* * 客户端 */ public class LoginClient { public static void main(String[] args) throws Exception, IOException { Socket socket = new Socket("localhost", 8000); // 发送请求 OutputStream os = socket.getOutputStream(); ObjectOutputStream oos =new ObjectOutputStream(os); User user =new User("Jack", "123456"); oos.writeObject(user); // 读回应 InputStream is = socket.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(is)); String replu = null; while ((replu = br.readLine()) != null) { System.out.println("我是客户端，服务器说：" + replu); } os.close(); oos.close(); socket.close(); } }
3、利用多线程实现多个客户端发出请求情况
①创建服务器线程类，run（）方法实现对一个请求的响应处理
②死循环让服务器一直处于监听状态
③服务器每监听一个线程，创建一个线程对象并启动
package demo3; import java.net.ServerSocket; import java.net.Socket; /* * 服务器 */ public class LoginServece { public static void main(String[] args) throws Exception { //建立连接 ServerSocket serverSocket= new ServerSocket(8000); Socket socket; while(true) { socket=serverSocket.accept(); MyThread thread =new MyThread(socket); thread.start(); } } }
package demo3; import java.io.IOException; import java.io.InputStream; import java.io.ObjectInputStream; import java.io.OutputStream; import java.net.Socket; public class MyThread extends Thread{ private Socket socket; public MyThread(Socket socket) { this.socket = socket; } @Override public void run() { //打开输入流 InputStream is=null; ObjectInputStream ois=null; OutputStream os=null; try { is = socket.getInputStream(); //读 ois = new ObjectInputStream(is); User user=(User) ois.readObject(); System.out.println(user); // 给回应 os=socket.getOutputStream(); String reply ="我是服务器，欢迎登陆"; os.write(reply.getBytes()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { //关闭资源 try { os.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { ois.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { is.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { socket.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }
package demo3; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.net.Socket; import java.net.UnknownHostException; /* * 客户端 */ public class LoginClient22 { public static void main(String[] args) throws Exception, IOException { Socket socket = new Socket("localhost", 8000); // 发送请求 OutputStream os = socket.getOutputStream(); ObjectOutputStream oos =new ObjectOutputStream(os); User user =new User("good", "111111"); oos.writeObject(user); // 读回应 InputStream is = socket.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(is)); String replu = null; while ((replu = br.readLine()) != null) { System.out.println("我是客户端，服务器说：" + replu); } os.close(); oos.close(); socket.close(); } }
四、InetAddress类
位于java.net包中，常用于封装IP地址和DNS
静态方法
InetAddress.getByName(String hostName)
返回指定主机名的InetAddress对象
五、基于UDP协议的socket编程
四个步骤
1、DatagramPacket对象封装数据包
2、DatagramSocket发送数据包
3、DatagramSocket接收数据包
4、DatagramPacket处理数据包
TCP和UDP协议的异同
实现实例：
package socket4; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; /* * 基于UDP协议的网络编程 */ public class LoginnServerce { public static void main(String[] args) { DatagramSocket socket=null; try { //接收客户端发过来的请求 //1、建立一个空包用来收 byte[] b =new byte[1024]; DatagramPacket dp = new DatagramPacket(b, b.length); //2、创建DatagramSocket，（快递点） socket =new DatagramSocket(8000); //3、收数据 socket.receive(dp); //读取数据 String info = new String(dp.getData(),0,dp.getData().length); System.out.println("客户端说："+info); //给客户端一个响应 String reply = "我是服务器，你好，客户端！"; DatagramPacket dp1=new DatagramPacket(reply.getBytes(), reply.getBytes().length, InetAddress.getByName("localhost"), 8000); //不用再创建socket socket.send(dp1); } catch (SocketException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(null!=socket) { socket.close(); } } } }
package socket4; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.Inet4Address; import java.net.InetAddress; import java.net.SocketException; import java.net.UnknownHostException; /* * 客户端 */ public class LoginClient { public static void main(String[] args) { String info="你好啊，服务器！"; byte[] infos=info.getBytes(); //获得一个InetAddress InetAddress address; DatagramSocket socket=null; try { address = Inet4Address.getByName("localhost"); //建立一个包裹封装数据 DatagramPacket dp =new DatagramPacket(infos,infos.length,address,8000); //建立快递点 socket =new DatagramSocket(); //通过快递点发送数据 socket.send(dp); //接收服务器发来的信息 //创建一个空包接收 byte[] b = new byte[1024]; DatagramPacket dp1 =new DatagramPacket(b, b.length); socket.receive(dp1); // 读取信息 String reply = new String(dp1.getData(), 0, dp1.getData().length); System.out.println(reply); } catch (UnknownHostException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SocketException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { socket.close(); } } }
