网络编程
如何实现网络的通信
- ip
- 端口号
- 192.168.1.1:3600
网络模型
TCP/IP四层概念模型:应用层、传输层、网络层、数据链路层 。
- 应用层:HTTP···
- 传输层:TCP/UDP
- 网络层:IP/ICMP···
- 数据链路层:FDDI、PPP···
TCP发送消息接受消息
tcp客户端
package com.seadun.demo.seadun.net.tcp;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
/*
* @desc tcp客户端
* @author qihao
* @date 2021/6/5 18:00
* @param
* @return
*/
public class TcpClientDemo01 {
public static void main(String[] args) {
Socket socket = null;
OutputStream outputStream = null;
// 1.我们要知道服务器地址端口号
try {
InetAddress address = InetAddress.getByName("127.0.0.1");
int port = 9999;
// 2. 我们创建一个socket连接
socket = new Socket(address, port);
// 3. 我们向socket发送io消息流
outputStream = socket.getOutputStream();
outputStream.write("特殊机密".getBytes());
System.out.println("你好,客户端已经发送消息");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (outputStream != null) {
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
tcp服务端(一直开启)
package com.seadun.demo.seadun.net.tcp;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
/*
* @desc tcp服务端
* @author qihao
* @date 2021/6/5 18:00
* @param
* @return
*/
public class TcpServiceDemo01 {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket socket = null;
InputStream inputStream = null;
ByteArrayOutputStream baos = null;
try {
// 要有一个地址端口,ip为localhost
serverSocket = new ServerSocket(9999);
while (true) {
// 等待客户端连接过来,使用serverSocket。accept进行接收
socket = serverSocket.accept();
// 读取客户端发过来的消息
inputStream = socket.getInputStream();
//该方法可能导致乱码,我们使用管道流
// byte[] buffer = new byte[1024];
// int len;
// while ((len = inputStream.read(buffer))!=-1){
// String s = new String(buffer, 0,len);
// System.out.println(s);
// }
// 管道流
baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) != -1) {
baos.write(buffer, 0, len);
}
System.out.println(baos.toString());
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (baos != null) {
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
UCP发送消息接受消息
ucp发送端
package com.seadun.demo.seadun.net.tcp;
import java.net.*;
/*
* @desc UDP无连接发送消息,UDP不区分客户端和服务端,都可以接受发送消息
* @author qihao
* @date 2021/6/5 20:34
* @param
* @return
*/
public class UdpDemo01 {
public static void main(String[] args) throws Exception {
//建立一个socket
DatagramSocket datagramSocket = new DatagramSocket();
//建个包
String msg = "你好,我们是UDP连接-重要机密";
InetAddress localhost = InetAddress.getByName("localhost");
int port = 9090;
//数据,数据的长度开始到结束,要发送给谁
DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port);
//发送包
datagramSocket.send(packet);
//关闭流
datagramSocket.close();
}
}
udp接受端
package com.seadun.demo.seadun.net.tcp;
/*
* @desc UDP无连接发送消息,UDP不区分客户端和服务端,都可以接受发送消息
* @author qihao
* @date 2021/6/5 20:35
* @param
* @return
*/
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
//还是要等待客户端的链接
public class UdpDemo02 {
public static void main(String[] args) throws IOException {
//开放端口
DatagramSocket datagramSocket = new DatagramSocket(9090);
byte[] buffer = new byte[1024];
//接受
DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
datagramSocket.receive(packet);
System.out.println(new String(packet.getData()));
datagramSocket.close();
}
}