打电话--连接--接了--通话 TCP
发信息--发送就完事了--接收 UDP(可能会掉包)
javaweb:网页编程 B/S架构(浏览器)
网络编程:TCP/IP C/S架构(客户端)
1.通信双方地址:ip 端口号
ip地址:InetAddress
唯一定位一台网络上计算机
127.0.0.1:自己的电脑 localhost
1.ipv4/ipv6:ipv4 127.0.0.1,4个字节组成(每个字节长度0-255,十进制点隔开)
ipv6 2409:8a20:2c19:7b60:e1be:5973:c280:e399(十六进制) 128位(2的128次方个字节) 8个无符号整数
2.公网(互联网)-私网(局域网)
ABCD类地址
192.168.xx.xx 局域网 专门给组织内部使用
域名:记忆ip问题 IP:www.vip.com
package WangLuoBianCheng;
import java.net.InetAddress;
import java.net.UnknownHostException;
// 测试IP
public class TestInetAddress {
public static void main(String[] args) {
try {//查询本机地址
InetAddress inetAddress3= InetAddress.getByName("localhost");
System.out.println(inetAddress3);
InetAddress inetAddress4= InetAddress.getLocalHost();
System.out.println(inetAddress4);
InetAddress inetAddress1= InetAddress.getByName("127.0.0.1");
System.out.println(inetAddress1);
//查询网络ip地址
InetAddress inetAddress2= InetAddress.getByName("www.baidu.com");
System.out.println(inetAddress2);
} catch (UnknownHostException e) {
throw new RuntimeException(e);
}
}
}
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!
被规定为0-65535
包含有有TCP,UDP:总共65535*2 TCP为80,UDP也可以是80,但在单个协议下,端口号不能冲突
1.公有端口 0-1023(尽量不要占用) 例:HTTP:80 HTTPS:443 FTP(文件传输):21
Telent(远程控制):23
2.程序注册端口:1024-49151,分配用户或者程序
Tomcat:8080 MySQL:3306 Oracle:1521
3.动态、私有(也不要放在这里面):49152-65535
网络通信协议:1.速率2.传输码率3.代码结构4.传输控制...
TCP/IP协议簇(实际上是一组协议) 重要的有:TCP:用户传输协议 UDP:用户数据报协议
出名的协议:TCP:用户传输协议 IP:网络互连协议
TCP:打电话
连接,稳定
三次握手,四次挥手:至少需要三次交流才能进行连接,a你在吗b我在a我也在。 至少需要四次交流才能断开连接:a我要走了 b我也要走了 b你走了嘛 a我走了
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
没有明确客户、服务端的界限
不管有没有准备好,都可以发给你
客户端
1.连接服务器Socket
2.发送消息
package WangLuoBianCheng.lesson02;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
//客户端
public class TcpClientDemo01 {
public static void main(String[] args) {
//IP地址不用提高定义域
Socket socket=null;
OutputStream os=null;
//1.要知道服务器的地址
try {
InetAddress serverIP = InetAddress.getByName("127.0.0.1");
//2.端口号
int port=9999;
//3.创建一个socket连接
socket = new Socket(serverIP,port);
//4.发送消息 IO流
os = socket.getOutputStream();
os.write("你好".getBytes());
} catch (Exception e) {
e.printStackTrace();
}finally {
if (os!=null){
try {
os.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
if (socket!=null){
try {
socket.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
}
服务端
1.建立服务的端口ServerSocket
2.等待用户的链接accept
3.接受用户的信息
package WangLuoBianCheng.lesson02;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
//服务端
public class TcpServerDemo01 {
public static void main(String[] args) {
ServerSocket serverSocket=null;
Socket socket=null;
InputStream is=null;
ByteArrayOutputStream baos=null;
{
try {
//1.我得先有一个地址
serverSocket = new ServerSocket(9999);//serversocket服务端套接字
//while (true) 循环接受
//2.等待客户端连接过来
socket = serverSocket.accept();//此时socket与客户端建立联系
//3.读取客户端信息
is = socket.getInputStream();
//管道流
baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while ((len = is.read(buffer)) != -1) {
baos.write(buffer, 0, len);
}
System.out.println(baos.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
//关闭资源
if (baos!=null){
try {
baos.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
if (is!=null){
try {
is.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
if (socket!=null){
try {
socket.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
if (serverSocket!=null){
try {
serverSocket.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
}
}
客户端
package WangLuoBianCheng.lesson01;
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
public class TcpClientDemo02 {
public static void main(String[] args) throws Exception {
//1.创建一个Socket连接
Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9000);
//2.创建一个输出流
OutputStream os=socket.getOutputStream();
//3.读取文件
FileInputStream fis = new FileInputStream(new File("1.jfif"));
//4.写出文件
byte[] buffer = new byte[1024];
int len;
while ((len=fis.read(buffer))!=-1){
os.write(buffer,0,len);
}
//通知服务器,我已经传输完了
socket.shutdownOutput();
//确定服务器接受完毕,才能够断开连接
InputStream inputStream = socket.getInputStream();
//String byte[]
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer2 = new byte[1024];
int len2;
while ((len2=inputStream.read(buffer2))!=-1){
baos.write(buffer2,0,len2);
}
System.out.println(baos.toString());
//5.关闭资源
fis.close();
os.close();
socket.close();
}
}
服务端
package WangLuoBianCheng.lesson01;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class TcpServerDemo02 {
public static void main(String[] args) throws IOException {
//1.创建服务端口
ServerSocket serverSocket = new ServerSocket(9000);
//2.监听客户端的连接
Socket socket = serverSocket.accept();//阻塞式监听,会一直等待客户端连接
//3.获取输入流
InputStream is=socket.getInputStream();
//4.文件输出流
FileOutputStream fos = new FileOutputStream(new File("receive.jfif"));
byte[] buffer = new byte[1024];
int len;
while ((len=is.read(buffer))!=-1){
fos.write(buffer,0,len);
}
//通知客户端我接收完毕了
OutputStream os=socket.getOutputStream();
os.write("我接收完毕了,你可以断开了".getBytes());
//关闭资源
fos.close();
is.close();
socket.close();
serverSocket.close();
}
}
发短息:不用连接,需要知道对方的地址
发送端
package WangLuoBianCheng.lesson03;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.nio.charset.StandardCharsets;
//不需要连接服务器
public class UdpClientDemo01 {
public static void main(String[] args) throws IOException {
//1.建立一个Socket
DatagramSocket socket = new DatagramSocket(0);
//2.建个包
String msg="你好啊,服务器!";
//发送给谁
InetAddress localhost = InetAddress.getByName("localhost");
int port=9090;
//数据,数据的长度,要发送给谁
DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port);
//3.发送包
socket.send(packet);
//4.关闭流
socket.close();
}
}
接收端
package WangLuoBianCheng.lesson03;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
//还要等待客户端的链接
public class UdpServerDemo01 {
public static void main(String[] args) throws Exception {
//开放端口
DatagramSocket socket = new DatagramSocket(9090);
//接收数据包
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
socket.receive(packet);//阻塞接收
System.out.println(packet.getAddress().getHostAddress());
System.out.println(new String(packet.getData(),0,packet.getLength()));
//关闭连接
socket.close();
}
}
循环发送消息
package WangLuoBianCheng.chat;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;
import java.nio.charset.StandardCharsets;
public class UdpSenderDemo01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(8888);
//准备数据:控制台读取System.in
BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
while (true){
String data=reader.readLine();
byte[] datas = data.getBytes();//转化为具体的数据
DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",6666));
socket.send(packet);
if (data.equals("bye")){
break;
}
}
}
}
循环接收消息
package WangLuoBianCheng.chat;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class UdpReceiveDemo01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666);
while (true) {
//准备接收包裹
byte[] container = new byte[1024];
DatagramPacket packet = new DatagramPacket(container, 0, container.length);
socket.receive(packet);//阻塞式接收包裹
//断开连接 说bye 自己输入bye来结束
byte[] data = packet.getData();
String receiveData = new String(data,0, packet.getLength());
System.out.println(receiveData);
if (receiveData.equals("bye")){
break;
}
}
}
}
统一资源定位符,定义互联网上的某一个资源
DNS域名解析(讲域名变成IP) www.baidu.com(域名) xxx.xxx..xx(IP) 域名的本质还是IP,域名更好记
https://www.baidu.com/
协议://ip地址:端口号
package WangLuoBianCheng.lesson04;
import Base.HelloWorld;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class UrlDown {
public static void main(String[] args) throws Exception{
//1.下载地址
URL url = new URL("https://image.baidu.com/search/detail?ct=503316480&z=0&ipn=d&word=%E5%9B%BE%E7%89%87&hs=0&pn=0&spn=0&di=7117150749552803841&pi=0&rn=1&tn=baiduimagedetail&is=0%2C0&ie=utf-8&oe=utf-8&cl=2&lm=-1&cs=2196812579%2C178847292&os=2981951213%2C133282478&simid=3419287875%2C189417273&adpicid=0&lpn=0&ln=30&fr=ala&fm=&sme=&cg=&bdtype=0&oriquery=%E5%9B%BE%E7%89%87&objurl=https%3A%2F%2Fgimg2.baidu.com%2Fimage_search%2Fsrc%3Dhttp%3A%2F%2Fimg.jj20.com%2Fup%2Fallimg%2F4k%2Fs%2F02%2F2109242332225H9-0-lp.jpg%26refer%3Dhttp%3A%2F%2Fimg.jj20.com%26app%3D2002%26size%3Df9999%2C10000%26q%3Da80%26n%3D0%26g%3D0n%26fmt%3Dauto%3Fsec%3D1666433043%26t%3D31583ae04a8f6793190cf2b1998c7eb7&fromurl=ippr_z2C%24qAzdH3FAzdH3Fooo_z%26e3B33da_z%26e3Bv54AzdH3F9hAzdH3Fu3AzdH3Fnmbnba_z%26e3Bip4s&gsm=100000000000001&islist=&querylist=&dyTabStr=MCwzLDEsNiw0LDUsMiw3LDgsOQ%3D%3D");
//2.连接到这个资源 HTTP
HttpURLConnection urlConnection=(HttpURLConnection)url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos = new FileOutputStream("555.jfif");
byte[] buffer = new byte[1024];
int len;
while ((len=inputStream.read(buffer))!=-1){
fos.write(buffer,0,len);
}
fos.close();
inputStream.close();
urlConnection.disconnect();//断开连接
}
}