网络编程
网络编程
1.1、IP
ip地址：InetAddress
- 唯一定位一台网络上计算机
- 127.0.0.1 ：本机localhost
- IP地址的分类
- IPV4、IPV6
- 公网（互联网）---私网（局域网）
- ABCD类地址
- 192.168.xx.xx
//测试IP
public class TestInetAddress {
public static void main(String[] args) {
try {
//查询本机地址
InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
System.out.println(inetAddress);
InetAddress inetAddress2 = InetAddress.getByName("localhost");
InetAddress inetAddress3 = InetAddress.getLocalHost();
System.out.println(inetAddress2);
System.out.println(inetAddress3);
//查询网站IP地址
InetAddress inetAddress4 = InetAddress.getByName("www.baidu.com");
System.out.println(inetAddress4);
} 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
-
单个协议下，端口号不能冲突
-
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
- Tomcat : 8080
- MySQ : 3306
- Oracle : 1521
- 动态、私有 ： 49152~65535
netstat -ano#查看所有端口 netstat -ano|findstr "8864" #查看指定端口 - 公有端口0~1023
1.3、通信协议
-
TCP
如打电话，连接，稳定，三次握手、四次挥手
-
UDP
如发短信，不连接，不稳定
1.4TCP
- 客户端
1.连接服务器 Socket
2.发送消息
//客户端
public class TcpClientDemo01 {
public static void main(String[] args) {
Socket socket=null;
OutputStream os=null;
try {
//1.要知道服务器的地址，端口号
InetAddress address=InetAddress.getByName("127.0.0.1");
int port=9999;
//2.创建一个socket连接
socket=new Socket(address,port);
//3.发送消息 IO流
os=socket.getOutputStream();
os.write("hello,world".getBytes());//哪个？？？？？？？？？？？？？？？？
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException 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.建立服务器端口 ServerSocket
2.等待用户来凝结 accept
3.接收用户消息
//服务器
public class TcpServerDemo01 {
public static void main(String[] args) {
ServerSocket serverSocket=null;
Socket socket=null;
InputStream inputStream=null;
ByteArrayOutputStream baos=null;
try {
//有一个地址
serverSocket=new ServerSocket(9999);
System.out.println("服务器已打开，等待客户连接...");
//等待客户端连接进来
socket=serverSocket.accept();
System.out.println("客户连接成功");
//读取客户端的消息
inputStream=socket.getInputStream();
//管道流
baos=new ByteArrayOutputStream();
byte[] bytes=new byte[1024];
int len;
while((len=inputStream.read(bytes))!=-1){
baos.write(bytes,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) {
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();
}
}
}
}
}
文件传输
-
服务器
//服务器2 文件上传 public class TcpServerDemo02 { public static void main(String[] args) throws Exception { //创建服务器 ServerSocket serverSocket=new ServerSocket(8888); System.out.println("服务器已打开，等待客户连接..."); Socket socket = serverSocket.accept(); System.out.println("客户连接成功"); //获取输入流 InputStream inputStream = socket.getInputStream(); //文件输出 FileOutputStream fos =new FileOutputStream(new File("copy轻音.png")); byte[] buffer =new byte[1024]; int len; while((len=inputStream.read(buffer))!=-1){ fos.write(buffer,0,len); } //通知客户端我接受完毕 OutputStream os=socket.getOutputStream(); os.write("服务器：我接受完毕,可以断开连接".getBytes()); //关闭资源 os.close(); fos.close(); inputStream.close(); socket.close(); serverSocket.close(); } } -
客户端
//客户端2 文件上传 public class TcpClientDemo02 { public static void main(String[] args) throws IOException { //创建Socket连接 Socket socket=new Socket("127.0.0.1",8888); //创建输出流 OutputStream os=socket.getOutputStream(); //读文件 FileInputStream fileInputStream=new FileInputStream("E:\\java123\\study-module\\qingyin.png");//为什么相对路径不行？？ //写文件 byte[] buffer =new byte[1024]; int len; while((len=fileInputStream.read(buffer))!=-1){ os.write(buffer,0,len); } //通知服务器，我已发送完毕 socket.shutdownOutput(); //确定服务器接收完毕，断开连接 InputStream inputStream=socket.getInputStream(); ByteArrayOutputStream baos=new ByteArrayOutputStream(); byte[] buffer2 =new byte[1024]; int len2; while((len2=inputStream.read(buffer))!=-1){ baos.write(buffer,0,len2); } System.out.println(baos.toString()); //关闭资源 baos.close(); inputStream.close(); fileInputStream.close(); os.close(); socket.close(); } }
1.5 UDP
发送消息
- 发送端
//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();
//建立一个包
String msg="hello,world!";
InetAddress localhost=InetAddress.getByName("localhost");
int port=9090;
DatagramPacket packet=new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);
//发送包
socket.send(packet);
//关闭流
socket.close();
}
}
- 接收端
public class UdpServerDemo01 {
public static void main(String[] args) throws IOException {
//开放端口
DatagramSocket socket=new DatagramSocket(9090);
//接收数据包
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
socket.receive(packet);//阻塞接收
System.out.println(packet.getAddress());
System.out.println(new String(packet.getData()));
//关闭端口
socket.close();
}
}
循环发送接收消息
- 发送端
public class UdpSenderDemo02 {
public static void main(String[] args) throws IOException {
//建立一个Socket
DatagramSocket socket=new DatagramSocket(8080);
//从控制台接收发送的消息
BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
while (true){
String msg=reader.readLine();
//从控制台接收发送的消息
//Scanner scanner=new Scanner(System.in);
//String msg=scanner.next();
DatagramPacket packet=new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,new InetSocketAddress("localhost",9090));
//发送包
socket.send(packet);
if (msg.equals("bye"))break;
}
//关闭流
socket.close();
}
}
- 接收端
public class UdpServerDemo02 {
public static void main(String[] args) throws IOException {
//开放端口
DatagramSocket socket=new DatagramSocket(9090);
while (true){
//接收数据包
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
socket.receive(packet);//阻塞接收
String s = new String(packet.getData(),0,packet.getLength());
System.out.println(packet.getAddress()+" "+s);
//结束判断
if (s.equals("bye")){
System.out.println("结束");
break;
}
}
//关闭端口
socket.close();
}
}
多线程在线聊天
- 发送功能对象
public class TalkSend implements Runnable{
DatagramSocket socket=null;
BufferedReader reader=null;
private String toIP;
private int toport;
private int fromport;
public TalkSend(String toIP, int toport,int fromport) {
this.toIP = toIP;
this.toport = toport;
this.fromport=fromport;
try {
socket = new DatagramSocket(fromport);
reader = new BufferedReader(new InputStreamReader(System.in));
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
while (true){
try {
String msg=this.reader.readLine();
byte[] bytes=msg.getBytes();
DatagramPacket packet=new DatagramPacket(bytes,0,bytes.length,new InetSocketAddress(this.toIP,this.toport));
//发送包
socket.send(packet);
if (msg.equals("bye"))break;
} catch (IOException e) {
e.printStackTrace();
}
}
//关闭流
socket.close();
}
}
- 接收功能对象
public class TalkReceive implements Runnable{
DatagramSocket socket=null;
private int port;
private int fromport;
public TalkReceive(int port,int fromport) {
this.port = port;
this.fromport=fromport;
try {
socket=new DatagramSocket(port);
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
while (true){
try {
//接收数据包
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
socket.receive(packet);//阻塞接收
String s = new String(packet.getData(),0,packet.getLength());
System.out.println("from "+fromport+":"+s);
//结束判断
if (s.equals("bye")) {
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
//关闭端口
socket.close();
}
}
- 用户1
public class TalkStudent {
public static void main(String[] args) {
//开启两个线程
new Thread(new TalkSend("localhost",9999,7777)).start();
new Thread(new TalkReceive(8888,6666)).start();
}
}
- 用户2
public class TalkSomeone {
public static void main(String[] args) {
new Thread(new TalkSend("localhost",8888,6666)).start();
new Thread(new TalkReceive(9999,5000)).start();
}
}
1.6URL
协议：//ip地址：端口/项目名/资源
public class URLDemo01 {
public static void main(String[] args) throws MalformedURLException {
URL url = new URL("https://m801.music.126.net/20210818194943/24d72ad156d84de41f049a4f99f8552b/jdyyaac/obj/w5rDlsOJwrLDjj7CmsOj/10362461644/c455/db10/ba72/cc9aa86a5f35bbd5456531bcd6bdf123.m4a");
System.out.println(url.getProtocol());//协议
System.out.println(url.getHost());//主机IP
System.out.println(url.getPort());//端口
System.out.println(url.getPath());//文件
System.out.println(url.getFile());//全路径
System.out.println(url.getQuery());//参数
}
}
- 下载网络资源
public class UrlDown {
public static void main(String[] args) throws IOException {
//下载地址
URL url = new URL("https://m881.music.126.net/20210818194943/24d72ad156d84de41f049a4f99f8552b/jdyyaac/obj/w5rDlsOJwrLDjj7CmsOj/10362461644/c455/db10/ba72/cc9aa86a5f35bbd5456531bcd6bdf123.m4a");
//连接到这个资源 HTTP
HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
InputStream inputStream=urlConnection.getInputStream();
FileOutputStream fos=new FileOutputStream("123.m4a");
byte[] bytes=new byte[1024];
int len;
while((len=inputStream.read(bytes))!=-1){
fos.write(bytes,0,len);//写这个数据
}
fos.close();
inputStream.close();
urlConnection.disconnect();//断开连接
}
}
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