Java 网络编程总结
作者:葛老头
这篇文章主要给大家分享Java 网络编程的一个总结,说到网络编程肯定都会想到IP地址、端口、通信协议等一些必不可少的元素,下面来看看文章的详细介绍吧
1、IP地址
IP地址IntAddress:
- 唯一定位一台网络上的计算机
- 127.0.0.1:本地localhost
- IP地址的分类
ipV4/ipV6
- ipV4:127.0.0.1,4个字节组成;0~255,42亿~;30亿都在北美,亚洲4亿;2011年就用完了
- ipV6:128位。8个无符号整数
公网(互联网)-私网(局域网)
- ABCD类地址
- 192.168 .xx.xx,专门给组织内部使用的
域名:方面记忆,免去了记录IP的问题
1 //测试IP 2 public class TestInetAddress { 3 public static void main(String[] args) { 4 try { 5 //查询本机地址 6 InetAddress inetAddress = InetAddress.getByName("127.0.0.1"); 7 System.out.println(inetAddress); 8 InetAddress localhost = InetAddress.getByName("localhost"); 9 System.out.println(localhost); 10 InetAddress localHost = InetAddress.getLocalHost(); 11 System.out.println(localHost); 12 13 //查询网站ip地址 14 InetAddress inetAddress1 = InetAddress.getByName("www.baidu.com"); 15 System.out.println(inetAddress1); 16 17 //常用方法 18 System.out.println(inetAddress1.getHostAddress());//ip 19 System.out.println(inetAddress1.getHostName());//域名,或者自己的名字 20 } catch (UnknownHostException e) { 21 e.printStackTrace(); 22 } 23 } 24 }
2、端口
ip相当于省/市/区/街/楼,端口就是门牌号;端口表示计算机上的一个程序的进程
- 不同的进程有不同的端口号!用来区分软件!
- 被规定0~65535
- TCP,UDP:65535*2;tcp:80;udp:80
- 端口分类
端口分类:
- 公有端口0~1023
- HTTP:80
- HTTPS:443
- FTP:21
- Telent:23
程序注册端口:1024~49151,分配用户或者程序
- Tomcat:8080
- MySQL:3306
- Orcal:1521
动态、私有:49152~65535
//CMD netstat -ano #查看所有的端口 netstat -ano|findstr "5900" #查看指定的端口 tasklist|findstr "8696" #查看指定端口的进程
1 //端口 2 public class TestInetSocketAddress { 3 public static void main(String[] args) { 4 InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080); 5 System.out.println(socketAddress); 6 7 System.out.println(socketAddress.getAddress()); 8 System.out.println(socketAddress.getHostName());//地址 9 System.out.println(socketAddress.getPort());//端口 10 } 11 }
3、通信协议
协议:约定,共同遵守,都能理解
网络通信协议:速率,传输码率,代码结构,传输控制....
3.1 TCP/IP协议簇:实际上是一组协议
重要:
TCP
:用户传输协议UDP
:用户数据报协议
3.2 TCP UDP对比
TCP:打电话
- 连接,稳定
- 三次握手,四次挥手
- 客户端、服务端
- 传输完成,释放连接,效率低
UDP:发短信
- 不连接,不稳定
- 客户端、服务端:没有明确的界限
- 不管有没有准备好,都可以发给你
3.3 TCP实现聊天
1 //服务端 2 public class TcpServerDemo01 { 3 public static void main(String[] args) { 4 ServerSocket serverSocket = null; 5 Socket accept=null; 6 InputStream is=null; 7 ByteArrayOutputStream baos=null; 8 try { 9 //1.得有一个地址 10 serverSocket = new ServerSocket(9999); 11 12 while (true){ 13 //2.等待客户端连接过来 14 accept = serverSocket.accept(); 15 //3.读取客户端得消息 16 is = accept.getInputStream(); 17 18 //管道流 19 baos = new ByteArrayOutputStream(); 20 byte[] bytes = new byte[1024]; 21 int len; 22 while ((len=is.read(bytes))!=-1){ 23 baos.write(bytes,0,len); 24 } 25 System.out.println(baos.toString()); 26 } 27 28 } catch (IOException e) { 29 e.printStackTrace(); 30 }finally { 31 //关闭流 32 try { 33 baos.close(); 34 } catch (IOException e) { 35 e.printStackTrace(); 36 } 37 try { 38 is.close(); 39 } catch (IOException e) { 40 e.printStackTrace(); 41 } 42 try { 43 accept.close(); 44 } catch (IOException e) { 45 e.printStackTrace(); 46 } 47 try { 48 serverSocket.close(); 49 } catch (IOException e) { 50 e.printStackTrace(); 51 } 52 53 } 54 } 55 } 1 //客户端 2 public class TcpClientDemo01 { 3 public static void main(String[] args) { 4 Socket socket=null; 5 OutputStream os=null; 6 7 try { 8 //1.要直到服务器得地址 9 InetAddress serverIP= InetAddress.getByName("127.0.0.1"); 10 int port=9999; 11 //2.创建一个socker连接 12 try { 13 socket = new Socket(serverIP,port); 14 //3.发送消息 IO流 15 os = socket.getOutputStream(); 16 os.write("Hello".getBytes()); 17 } catch (IOException e) { 18 e.printStackTrace(); 19 } 20 21 22 } catch (UnknownHostException e) { 23 e.printStackTrace(); 24 }finally { 25 try { 26 os.close(); 27 } catch (IOException e) { 28 e.printStackTrace(); 29 } 30 try { 31 socket.close(); 32 } catch (IOException e) { 33 e.printStackTrace(); 34 } 35 } 36 } 37 }
3.4 TCP文件上传
1 //服务端 2 public class TcpServerDemo02 { 3 public static void main(String[] args) throws Exception{ 4 //1.创建服务 5 ServerSocket serverSocket = new ServerSocket(9000); 6 //2.监听客户端得连接 7 Socket accept = serverSocket.accept();//阻塞式监听,会一直等待客户端得连接 8 //3.获取输入流 9 InputStream is = accept.getInputStream(); 10 11 //4.文件输出 12 FileOutputStream fos = new FileOutputStream("receive.jpg"); 13 byte[] by = new byte[1024]; 14 int len; 15 while ((len=is.read(by))!=-1){ 16 fos.write(by,0,len); 17 } 18 19 //通知客户端我接收完毕了 20 OutputStream os = accept.getOutputStream(); 21 os.write("接收完毕".getBytes()); 22 23 os.close(); 24 fos.close(); 25 is.close(); 26 accept.close(); 27 serverSocket.close(); 28 } 29 } 1 //客户端 2 public class TcpClientDemo02 { 3 public static void main(String[] args) throws Exception{ 4 //1.创建一个socket连接 5 Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9000); 6 //2.创建一个输出流 7 OutputStream os = socket.getOutputStream(); 8 9 //3.读取文件 10 FileInputStream fis = new FileInputStream("D:\\WorkSpace\\JavaSE\\基础语法\\111.png"); 11 //4.写出文件 12 byte[] by = new byte[1024]; 13 int len; 14 while ((len=fis.read(by))!=-1){ 15 os.write(by,0,len); 16 } 17 18 //通知服务器,我已经传输结束了 19 socket.shutdownOutput(); 20 21 //确认服务器接收完毕,才能断开连接 22 InputStream is = socket.getInputStream(); 23 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 24 25 byte[] bytes = new byte[1024]; 26 int leng; 27 while ((leng=is.read(bytes))!=-1){ 28 baos.write(bytes,0,leng); 29 } 30 System.out.println(baos.toString()); 31 32 baos.close(); 33 is.close(); 34 os.close(); 35 fis.close(); 36 socket.close(); 37 } 38 }
3.5 UDP消息发送
1 //发送方 2 public class UdpClientDemo01 { 3 public static void main(String[] args) throws Exception{ 4 //1.建立一个Socket 5 DatagramSocket datagramSocket = new DatagramSocket(); 6 7 //2.建个包 8 String msg="你好啊,服务器!"; 9 InetAddress localhost = InetAddress.getByName("localhost"); 10 int port = 9090; 11 12 //数据、数据的长度起始、要发给谁 13 DatagramPacket datagramPacket = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port); 14 15 //发送包 16 datagramSocket.send(datagramPacket); 17 18 //4.关闭流 19 datagramSocket.close(); 20 } 21 } 1 //接收方 2 public class UdpServerDemo01 { 3 public static void main(String[] args) throws Exception{ 4 //开放端口 5 DatagramSocket datagramSocket = new DatagramSocket(9090); 6 //接收数据 7 byte[] bytes = new byte[1024]; 8 DatagramPacket datagramPacket = new DatagramPacket(bytes,0,bytes.length); 9 10 datagramSocket.receive(datagramPacket);//阻塞接收 11 12 System.out.println(datagramPacket.getAddress()); 13 System.out.println(new String(datagramPacket.getData(),0,datagramPacket.getLength())); 14 } 15 }
3.6 UDP聊天实现
1 //发送方 2 public class UdpSenderDemo01 { 3 public static void main(String[] args) throws Exception{ 4 5 DatagramSocket datagramSocket = new DatagramSocket(8888); 6 7 //准备数据:控制台读取System.in 8 BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); 9 10 while (true){ 11 String data=reader.readLine(); 12 byte[] bytes = data.getBytes(); 13 DatagramPacket datagramPacket = new DatagramPacket(bytes,0,bytes.length,new InetSocketAddress("localhost",6666)); 14 datagramSocket.send(datagramPacket); 15 if(bytes.equals("byebye")){ 16 break; 17 } 18 } 19 datagramSocket.close(); 20 } 21 } 1 //接收方 2 public class UdpReceiveDemo01 { 3 public static void main(String[] args) throws Exception{ 4 DatagramSocket datagramSocket = new DatagramSocket(6666); 5 6 while (true){ 7 //准备接收包裹 8 byte[] bytes = new byte[1024]; 9 DatagramPacket datagramPacket = new DatagramPacket(bytes,0,bytes.length); 10 11 //断开连接 byebye 12 byte[] data = datagramPacket.getData(); 13 String string = new String(data, 0, data.length); 14 System.out.println(string); 15 if(string.equals("byebye")){ 16 break; 17 } 18 } 19 20 datagramSocket.close(); 21 22 } 23 }
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