Java学习笔记（十五）15Java网络编程，TCP实现聊天，文件上传，UDP发送消息，聊天，多线程咨询，URL
网络编程
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计算机网络：
- 计算机网络是指将地理位置不同的具有独立功能的多台计算机及其外部设备，通过通信线路连接起来，在网络操作系统，网络管理软件及网络通信协议的管理和协调下，实现资源共享和信息传递的计算机系统。
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网络编程的目的
- 无线电台，传播交流信息
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想要达到这个效果需要什么
- 如何准确的定位网络上的一台主机192.168.16.124：端口，定位到这个计算机的某个资源
- 找到了这个主机，如何传输数据
- javaweb：网页编程 B/S
- 网络编程：TCP/IP S/C
网络通信的要素
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如何实现网络的通信？
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通信双方的地址：
- ip
- 端口号
- ip：端口号—>192.168.16.124.5900
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规则：网络通信协议
- TCP/IP参考模型
IP
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ip地址：关键字InetAddress
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唯一定位一台网络上的计算机
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127.0.0.1：本机localhost
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ip地址的分类
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ipv4 127.0.0.1，4个字节组成，0~255，42亿；已用尽
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ipv6：128位。8个无符号的证书
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2001:0bb2:aaaa:0015:0000:0000:1aaa:1312
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公网（互联网）-私网（局域网）
- ABCD类地址
- 192.169.xx.xx,专门给组织北部使用的
-
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域名：用来记忆IP（www.vip.com）
端口
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端口便是计算机上一个程序的进程：
-
不同的进程有不同的端口号，用来区分不同的软件
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被规定的端口号TCP,UDP数量为0~65535 *2
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单个协议下，端口号不能冲突
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端口分类
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公有端口0~1023
- HTTP:80
- HTTPS:443
- FTP:21
- Telent：23
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程序注册端口：1024~49151，分配用户或者程序使用
- Tomcat：8080
- MySQL：3306
- Oracle：1521
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动态、私有：49152~65535
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-
TCP Udp对比
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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：发信息
- 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
- 导弹
- DDOS:洪水攻击！
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-
简单的服务器客户端模拟
//服务器 package Net; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.ServerSocket; import java.net.Socket; public class TcpSeriverDemo01 { public static void main(String[] args) { ServerSocket serverSocket=null; Socket socket=null; InputStream is =null; ByteArrayOutputStream baos =null; try { serverSocket=new ServerSocket(9999);//创建一个地址 socket=serverSocket.accept();//等待客户端连接 is = socket.getInputStream();//读取客户端信息 baos=new ByteArrayOutputStream();//管道流 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) { 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(); } } } } } //客户端 package Net; import java.io.IOException; import java.io.OutputStream; import java.net.InetAddress; import java.net.Socket; import java.net.UnknownHostException; public class TcpClientDemo01 { //要知道服务器 地址 public static void main(String[] args) { Socket socket = null; OutputStream os=null; try { InetAddress serverIP = InetAddress.getByName("127.0.0.1");//得到服务器的地址和端口号 int port = 9999; socket=new Socket(serverIP,port);//创建一个socket连接 os=socket.getOutputStream();//发送信息IO流 os.write("北京欢迎你".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(); } } } } }
TCP
- 客户端：连接服务器Socket–>发送信息
- 服务器：创建服务端口ServerSocket–>等待用户的连接accept–>接收用户信息
文件传输 关键字：FileInputStream，FileoutputStream
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服务器
package Net.Demo02; import java.io.*; import java.net.ServerSocket; import java.net.Socket; import java.net.SocketAddress; public class TcpServerDemo02 { public static void main(String[] args) throws Exception { ServerSocket serverSocket=new ServerSocket(9000); Socket socket = serverSocket.accept(); InputStream is =socket.getInputStream(); FileOutputStream fos =new FileOutputStream(new File("receive.jpg")); byte[] buffer=new byte[1024]; int len; while ((len=is.read(buffer))!=-1){ fos.write(buffer,0,len); } OutputStream os=socket.getOutputStream(); os.write("接收完毕".getBytes()); fos.close(); is.close(); socket.close(); serverSocket.close(); } } -
客户端
package Net.Demo02; import java.io.*; import java.net.InetAddress; import java.net.Socket; public class TcpClientDemo02 { public static void main(String[] args) throws Exception { InetAddress address= InetAddress.getByName("127.0.0.1"); Socket socket=new Socket(address,9000); OutputStream os= socket.getOutputStream(); FileInputStream fis=new FileInputStream(new File("yanzi.jpg")); byte[] buffer=new byte[1024]; int len; while ((len=fis.read(buffer))!=-1){ os.write(buffer,0,len); } socket.shutdownOutput(); InputStream is =socket.getInputStream(); ByteArrayOutputStream baos=new ByteArrayOutputStream(); byte[] buffer2=new byte[2014]; int lens; while((len=is.read(buffer2))!=-1){ baos.write(buffer2,0,len); } System.out.println(baos.toString()); fis.close(); os.close(); socket.close(); } }
Tomcat
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服务端
- 自定义s
- Tomcat服务器S：java后台开发！
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客户端
- 自定义C
- 浏览器B
UDP发送信息
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不需要连接服务器：关键字：DatagramSocket
-
服务器
package Net.Demo03; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; public class UdpServerDemo01 { public static void main(String[] args) throws Exception { DatagramSocket socket=new DatagramSocket(9090); byte[] buffer=new byte[1024]; DatagramPacket packet=new DatagramPacket(buffer,0,buffer.length); socket.receive(packet); System.out.println(packet.getAddress().getHostAddress()); System.out.println(new String(packet.getData(),0,packet.getLength())); socket.close(); } } -
客户端
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package Net.Demo03;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
public class UdpClientDemo01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket=new DatagramSocket();
String msg="你好，服务器！";
InetAddress localhost=InetAddress.getByName("127.0.0.1");
int port=9090;
DatagramPacket packet=new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);
socket.send(packet);
socket.close();
}
}
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初步聊天实现
- 客户端
package Net.Demo04; import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.*; public class UdpsenderDemo01 { public static void main(String[] args) throws Exception { DatagramSocket socket=new DatagramSocket(); BufferedReader reader=new BufferedReader(new InputStreamReader(System.in)); while (true){ String data=reader.readLine(); byte[] datas= data.getBytes(); DatagramPacket packet =new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",6666)); socket.send(packet); if (data.equals("bye")){ break; } } socket.close(); } }- 接收端
package Net.Demo04; 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){ byte[] container=new byte[1024]; DatagramPacket packet=new DatagramPacket(container,0,container.length); socket.receive(packet); byte[] data=packet.getData(); String receiveData=new String(data,0,data.length); System.out.println(receiveData); if (receiveData.equals("bye")){ break; } } socket.close(); } }
多线程咨询
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发送端
package Net.Demo05; import org.jcp.xml.dsig.internal.dom.ApacheOctetStreamData; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress; import java.net.SocketException; public class TalkSend implements Runnable{ DatagramSocket socket=null; BufferedReader reader=null; private int fromPort; private String toIP; private int toport; public TalkSend(int fromPort, String toIP, int toport) { this.fromPort = fromPort; this.toIP = toIP; this.toport = toport; try { socket=new DatagramSocket(fromPort); reader=new BufferedReader(new InputStreamReader(System.in)); } catch (Exception e) { e.printStackTrace(); } } @Override public void run() { while (true){ try { String data=reader.readLine(); byte[] datas =data.getBytes(); DatagramPacket packet=new DatagramPacket(datas,0,datas.length,new InetSocketAddress(this.toIP,this.toport)); socket.send(packet); if (data.equals("bye")){ break; } } catch (IOException e) { e.printStackTrace(); } } socket.close(); } } -
接收端
package Net.Demo05; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; public class TalkReceive implements Runnable{ DatagramSocket socket=null; private int port; private String msgFrom; public TalkReceive(int port,String msgFrom) { this.port = port; this.msgFrom=msgFrom; try { socket=new DatagramSocket(port); } catch (Exception e) { e.printStackTrace(); } } @Override public void run() { while (true){ try { byte[] container=new byte[1024]; DatagramPacket packet=new DatagramPacket(container,0,container.length); socket.receive(packet); byte[] data=packet.getData(); String receiveData=new String(data,0,data.length); System.out.println(msgFrom+":"+receiveData); if (receiveData.equals("bye")){ break; } } catch (IOException e) { e.printStackTrace(); } } socket.close(); } } -
A
package Net.Demo05; public class TalkStudent { public static void main(String[] args) { new Thread(new TalkSend(7777,"localhost",9999)).start(); new Thread(new TalkReceive(8888,"老师")).start(); } } -
B
package Net.Demo05; public class TalkTeacher { public static void main(String[] args) { new Thread(new TalkSend(5555,"localhost",8888)).start(); new Thread(new TalkReceive(9999,"学生")).start(); } }
URL
- 统一资源定位符：定位资源得，定位互联网上得某一个资源
- DNS 域名解析 www.baidu.com: xxx.x…x…x
- 协议：//ip地址：端口/项目名/资源
package Net.PA;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class UrlDown {
public static void main(String[] args) throws Exception {
URL url=new URL("https://ws.stream.qqmusic.qq.com/C400002zpsxr1TlBvY.m4a?guid=7983659658&vkey=5EF7C88327DF6EDC07FB84C564CB1884F2D0B9AE7AACE0A72C8B387FB122CF1B1586FA8B6DE434A00A74B55AAE314FB2806E0C4C6B4F7DC9&uin=7739&fromtag=66");
HttpURLConnection urlConnection=(HttpURLConnection) url.openConnection();
InputStream inputStream=urlConnection.getInputStream();
FileOutputStream fos =new FileOutputStream("f.m4a");
byte[] buffer=new byte[1024];
int len;
while ((len=inputStream.read(buffer))!=-1){
fos.write(buffer,0,len);
}
fos.close();
inputStream.close();
urlConnection.disconnect();
}
}