网络编程基础
网络编程
1.1 IP
ip：地址inetAddress
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：
ip地址分类：
ipv4/ipv6
ipv4：127.0.0.1 由四个字节组成，0-255，42亿；30亿都在北美，亚洲4亿，2011年就已经用尽
ipv6：128位，8个无符号整数表示，adcde 2001：0bb2：aaaa：...
公网（互联网）-私网（局域网）：
192.168.xx.xx 专门给组织内存使用的
域名：记忆ip问题
package Ip01;
import java.net.InetAddress;
import java.net.UnknownHostException;
//测试ip
public class TestInetAddress {
public static void main(String[] args) throws UnknownHostException {
try {
//查询本机地址
InetAddress inetAddresses1 = InetAddress.getByName("127.0.0.1");
System.out.println(inetAddresses1);
InetAddress inetAddresses3 = InetAddress.getByName("localhost");
System.out.println(inetAddresses3);
InetAddress inetAddresses4 = InetAddress.getLocalHost();
System.out.println(inetAddresses4);
//查询网站ip
InetAddress inetAddresses2 = InetAddress.getByName("www.baidu.com");
System.out.println(inetAddresses2);
//常用方法
}catch (UnknownHostException e){
e.printStackTrace();
}
}
}
1.2端口
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 单个协议下，端口号不能冲突
端口分离
公有端口 0-1023
http：80
https：443
ftp：21
telent：23
程序注册端口 ：1024-49151 分配给用户或者程序
Tomcat:8080
MySQL:3306
Gracle:1521
动态，私有端口：49152-65535
netstat - ano//查询所有的窗口
netstat -ano｜ findstr"xxx"//查询指定的端口
tasklist|findstr"xx"//查看置顶端口的进程
TCP UDP的区别
TCP:打电话
连接稳定
三次握手，四次挥手
客户端，服务端
UDP：发短信
不连接，不稳定
客服端，服务端；没有明确的界限
不管有没有准备好，都可以发给你。。
导弹
DDOS:洪水攻击（饱和攻击）
1.3 TCP
客服端
1,连接服务器socker
2，发送消息
package TCP;
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) {
//1,要知道服务器的地址
Socket socket = null;
OutputStream os = null;
try {
InetAddress serverIP = InetAddress.getByName("127.0.0.1");
int port = 9999;
////3,创建一个socket连接
socket = new Socket(serverIP,port);
// 发送消息
os = socket.getOutputStream();
os.write("你好".getBytes());
} catch (Exception e) {
e.printStackTrace();
}finally {
if (os != null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (socket != null){
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
服务器
1，建立服务的窗口
2，等待用户的连接accept
3，接受客服端消息
package TCP;
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，我要有一个地址
serverSocket = new ServerSocket(9999);
//2,等待客户端链接进来
socket = serverSocket.accept();
//3,读取客户端的消息
is = socket.getInputStream();
// 管道流
baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length;
while ((length=is.read(buffer)) != -1){
baos.write(buffer,0,length);
}
System.out.println(baos.toString());
} catch (IOException e) {
e.printStackTrace();
}finally {
if (baos != null){
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (is != null){
try {
is.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();
}
}
}
}
}
文件上传
package TCP;
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("Tx.jpeg"));
//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，我已经结束了
socket.shutdownOutput();//我已经完了
//确定服务器接受完毕才能断开连接
InputStream inputStream = socket.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer2 = new byte[2014];
int len2;
while ((len2=inputStream.read(buffer2))!= -1){
baos.write(buffer2,len2,0);
}
System.out.println(baos.toString());
baos.close();
inputStream.close();
fis.close();
os.close();
socket.close();
}
}
package TCP;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class TcpServerDome02 {
public static void main(String[] args) throws Exception {
//1，创建服务
ServerSocket severSocket = new ServerSocket(9000);
//2,监听客户端的连接
Socket socket = severSocket.accept();//组塞式监听，会一直等待客户端链接
//3，获取输入流
InputStream is = socket.getInputStream();
//4,文件输出
FileOutputStream fos = new FileOutputStream(new File("receive.jpeg"));
byte[] buffer = new byte[1024];
int len;
while ((len=is.read(buffer)) !=1){
fos.write(buffer,len,0);
}
//通知客户端我接受完毕了
OutputStream os = socket.getOutputStream();
os.write("我接受完毕了".getBytes());
fos.close();
is.close();
socket.close();
severSocket.close();
}
}
Tomcat
服务器
1，自定义s
2，Tomcat服务器S:java后台开发
客户端
1，自定义c
2，浏览器b
1.4 UDP
发短信：不用连接，需要知道对方的地址
package UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.nio.charset.StandardCharsets;
// 不需要连接服务器
public class UdpClientDemo01 {
public static void main(String[] args) throws Exception {
//1，建立一个socket
DatagramSocket socket = new DatagramSocket();
//2，建个包
String msg = "nihao";
InetAddress localhost = InetAddress.getByName("localhost");
int port = 9990;
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();
}
}
package UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
//还是要等待客户端的连接
public class UdpSeverDemo01 {
public static void main(String[] args) throws Exception {
//开放端口
DatagramSocket socket = new DatagramSocket(9090);
//接受数据
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
socket.receive(packet);//阻塞接受
System.out.println(packet.getAddress().getHostAddress());
System.out.println(new String(packet.getData(),0,packet.getLength()));
socket.close();
}
}
1.5URL
package URL;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class URLDemo01 {
public static void main(String[] args) throws IOException {
URL url = new URL("");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos = new FileOutputStream();
byte[] buffer = new byte[2014];
int len;
while ((len=inputStream.read(buffer))!= -1){
fos.write(buffer,len,0);
fos.close();
inputStream.close();
urlConnection.disconnect();
}
}
}
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