网络编程概述

基本概念

IP地址概念

终端检查：

InetAddress

package heima.网络编程;import java.net.InetAddress;
import java.net.UnknownHostException;public class inetaddress {public static void main(String[] args) throws UnknownHostException {//public static InetAddress getByName(String host)：确定主机名称的IP地址，主机名称可以是机器名称，也可以是IP地址
//        InetAddress address = InetAddress.getByName("ludan");InetAddress address = InetAddress.getByName("192.168.3.55");//public String getHostName()：获取此IP地址的主机名。String name = address.getHostName();//public String getHostAddress()：返回文本显示中的IP地址字符串。String ip = address.getHostAddress();System.out.println("主机名："+name);System.out.println("IP地址："+ip);}
}

端口与协议概念

UDP通信编程

UDP发送数据

package heima.网络编程;import java.io.IOException;
import java.net.*;public class udp {public static void main(String[] args) throws IOException {//创建发送端的Socket对象(DatagramSocket)//public DatagramSocket() 构造数据报套接字并将其绑定到本地主机上的任何可用端口。DatagramSocket ds = new DatagramSocket();//创建数据，并把数据打包//DatagramPacket (byte[] buf,int length,InetAddress address,int part)//构造一个数据包，发送长度为length的数据包到指定主机上的指定端口号。byte[] bys = "hello,udp，我来了".getBytes();DatagramPacket dp = new DatagramPacket(bys, bys.length, InetAddress.getByName("192.168.3.55"),8080);//way2
//        int length = bys.length;
//        InetAddress address = InetAddress.getByName("192.168.3.55");
//        int part = 10086;
//        DatagramPacket dp = new DatagramPacket(bys,length,address,part);//调用DatagramSocket对象的方法发送数据//void send(DatagramSocket p) 从此套接字发送数据包ds.send(dp);//关闭发送端//void vlose() 关闭此数据报套接字ds.close();}
}

UDP接受数据

package heima.网络编程;import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;public class ReceiveUDP {public static void main(String[] args) throws IOException {//参加接受端的Socket对象(DatagramSocket)//DatagramSocket (int part) 构造数据报套接字并将其绑定到本地主机上的指定端口DatagramSocket ds = new DatagramSocket(8080);//创建一个数据包，用于接收数据//DatagramSocket(byte[] buf,int length) 构造一个DatagramPacket用于接收长度为length数据byte[] bys = new byte[1024];DatagramPacket dp = new DatagramPacket(bys, bys.length);//调用DatagramSocket对象的方法接收数据ds.receive(dp);//解析数据包,并把数在控制台显示//byte[] getData() 返回数据缓冲区
//        byte[] datas = dp.getData();//int getlength() 返回要发送的数据长度或接受到的数据的长度
//        int len = dp.getLength();
//        String dataString = new String(datas,0,len);
//        System.out.println("数据是："+dataString);System.out.println("数据是："+new String(dp.getData(),0,dp.getLength()));//关闭接收端ds.close();}
}

很奇怪，接受不到数据。。

UDP通信程序练习

创建了一个item03的路径，在此路径下：
udp1.java

package heima.网络编程.item03;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.UnknownHostException;public class udp1 {public static void main(String[] args) throws IOException {//创建发送端的Socket对象(DatagramSocket)DatagramSocket ds = new DatagramSocket();//自己封装键盘录入数据BufferedReader br = new BufferedReader(new InputStreamReader(System.in));String line;while ((line = br.readLine())!=null){//输入的数据是886,发送数据结束if ("886".equals(line)){break;}//创建数据，并把数据打包byte[] bys = line.getBytes();DatagramPacket dp = new DatagramPacket(bys, bys.length, InetAddress.getByName("192.168.3.55"),12345);//调用DatagramPacket对象的方法发送数据ds.send(dp);}//关闭发送源ds.close();}
}

Receive.java

package heima.网络编程.item03;import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;public class Receive1 {public static void main(String[] args) throws IOException {//创建接收端Socket对象(DatagramSocket)DatagramSocket ds = new DatagramSocket(12345);while (true){//创建一个数据包，用于接收数据byte[] bys = new byte[1024];DatagramPacket dp = new DatagramPacket(bys, bys.length);//调用DatagramSocket对象的方法接收数据ds.receive(dp);//解析数据包，并把数据在控制台显示System.out.println("数据是："+new String(dp.getData(),0,dp.getLength()));}//        //关闭接收端
//        ds.close();//因为要一直接收数据，所以它也不用关了}
}

TCP通信编程

TCP发送数据

package heima.网络编程.item04;import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {//创建客户端的Socket对象(Socket)//Socket(InetAddress address,int part) 创建流套接字并将其连接到指定的IP地址的指定端口号
//        Socket s = new Socket(InetAddress.getByName("192.168.3.55"),10000);//Socket(String host,int part)创建流套接字并将其连接到指定主机上的指定端口号Socket s = new Socket("192.168.3.55",10000);//获取输出流，写数据//OutputStream getOutputStream() 返回此套接字的输出流OutputStream os = s.getOutputStream();os.write("hello,tcp,我来了".getBytes());//释放资源s.close();}
}

现在运行会报错，是因为还缺少TCP数据的接收

TCP接收数据

package heima.网络编程.item04;import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {//创建客户端的Socket对象(Socket)//Socket(InetAddress address,int part) 创建流套接字并将其连接到指定的IP地址的指定端口号
//        Socket s = new Socket(InetAddress.getByName("192.168.3.55"),10000);//Socket(String host,int part)创建流套接字并将其连接到指定主机上的指定端口号Socket s = new Socket("192.168.3.55",12345);//获取输出流，写数据//OutputStream getOutputStream() 返回此套接字的输出流OutputStream os = s.getOutputStream();os.write("hello,tcp,我来了".getBytes());//释放资源s.close();}
}

TCP通信程序练习

• 练习1 --服务器给出反馈
  
  

package heima.网络编程.P349;import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {//创建客户端的Socket对象Socket s = new Socket("192.168.3.55",12345);//获取输出流，写数据OutputStream os = s.getOutputStream();os.write("hello,tcp,我来了".getBytes());//接受服务器反馈InputStream is = s.getInputStream();byte[] bys = new byte[1024];int len = is.read(bys);String data = new String(bys,0,len);System.out.println("客户端："+data);//释放资源s.close();}
}

package heima.网络编程.P349;import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {//创建服务端的Socket对象ServerSocket ss = new ServerSocket(12345);//监听客户端连接，返回一个Socket对象Socket s = ss.accept();//获取输入流，读数据，并把数据显示在控制台InputStream is = s.getInputStream();byte[] bys = new byte[1024];int len = is.read(bys);String data = new String(bys,0,len);System.out.println("服务器："+data);//给出反馈OutputStream os = s.getOutputStream();os.write("数据已收到".getBytes());//释放资源ss.close();}
}

注：

1. 只释放Socket对象就ok了，其他不用再释放
2. 端口报错，就换一个端口

• 练习2 --客户数据来自于键盘录入

package heima.网络编程.TPC练习2;import java.io.*;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {Socket s = new Socket("192.168.3.55",12345);//数据来自于键盘录入，知道输入的是886，发送数据结束BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//封装输出流对象BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));String line;while ((line= br.readLine())!=null){if ("886".equals(line)){break;}//获取输出流对象bw.write(line);bw.newLine();bw.flush();}//释放资源4s.close();}
}

package heima.网络编程.TPC练习2;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {//创建服务器Socket对象ServerSocket ss = new ServerSocket(12345);//监听客户端的连接，返回一个对应的Socket对象Socket s = ss.accept();//获取输入流BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));String line;while ((line = br.readLine())!=null){System.out.println(line);}//释放资源ss.close();}
}

在ClientDemo.java终端输入，则在ServerDemo处输出，知道输入886为止

• 练习3 --服务器数据写入文本文件

package heima.网络编程.TPC练习3;import java.io.*;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {Socket s = new Socket("192.168.3.55",12345);//数据来自于键盘录入，知道输入的是886，发送数据结束BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//封装输出流对象BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));String line;while ((line=br.readLine())!=null){if ("886".equals(line)){break;}//获取输出流对象bw.write(line);bw.newLine();bw.flush();}//释放资源s.close();}
}

package heima.网络编程.TPC练习3;import kuang.P70.B;import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {//创建服务器Socket对象ServerSocket ss =new ServerSocket(12345);//监听客户端连接，返回一个对应的Socket对象Socket s = ss.accept();//接收数据BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));//把数据写入文本文件BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\Users\\路聃\\Desktop\\Java\\s.txt"));String line;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//释放资源bw.close();ss.close();}
}

输出：

• 练习4 --客户端数据来自文本文件

莫名出错

package heima.网络编程.TPC练习4;import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {ServerSocket ss = new ServerSocket(12345);Socket s = ss.accept();BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\Users\\路聃\\Desktop\\Java\\1.txt"));String line;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//释放资源bw.close();ss.close();}
}

package heima.网络编程.TPC练习4;import java.io.*;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {Socket s =new Socket("192.168.3.55",12345);BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\路聃\\Desktop\\Java\\s.txt"));BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));String line;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//释放资源br.close();s.close();}
}

• 练习5 --上传文件服务器给出的反馈

package heima.网络编程.TPC练习5;import java.io.*;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {Socket s = new Socket("192.168.3.55",10000);BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\路聃\\Desktop\\Java\\s.txt"));BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));String line;;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//public void shutdownOutput() --非自定义结束标记s.shutdownInput();//接收反馈BufferedReader brClient = new BufferedReader(new InputStreamReader(s.getInputStream()));String data = brClient.readLine();System.out.println("服务器的反馈："+data);//释放资源br.close();s.close();}
}

package heima.网络编程.TPC练习5;import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {ServerSocket ss = new ServerSocket(10000);Socket s = ss.accept();BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\Users\\路聃\\Desktop\\Java\\Copy.txt"));String line;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//给出反馈BufferedWriter bwServer = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));bwServer.write("文件上传成功");bwServer.newLine();bwServer.flush();}
}

连接端口失败，原因未知

• 练习6 --多线陈实现文件上传

package heima.网络编程.TPC练习6;import java.io.*;
import java.net.Socket;public class ClientDemo {public static void main(String[] args) throws IOException {Socket s = new Socket("192.168.3.55",12345);BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\路聃\\Desktop\\Java\\s.txt"));BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));String line;;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}//public void shutdownOutput() --非自定义结束标记s.shutdownInput();//接收反馈BufferedReader brClient = new BufferedReader(new InputStreamReader(s.getInputStream()));String data = brClient.readLine();System.out.println("服务器的反馈："+data);//释放资源br.close();s.close();}
}

package heima.网络编程.TPC练习6;import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;public class ServerDemo {public static void main(String[] args) throws IOException {//创建服务器Socket对象ServerSocket ss = new ServerSocket(12345);while (true){//监听客户端连接，返回一个对应的Socket对象Socket s = ss.accept();//为每一个客户端开启一个线程new Thread(new ServerThread(s)).start();}//为什么不释放资源了？}
}

package heima.网络编程.TPC练习6;import java.io.*;
import java.net.Socket;public class ServerThread implements Runnable{private Socket s;public ServerThread(Socket s){this.s = s;}@Overridepublic void run() {try {//接收数据写到文本文件BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));//解决名称冲突问题int count = 0;File file = new File("C:\\Users\\路聃\\Desktop\\Java\\Copy["+count+"].java");while (file.exists()){count++;file = new File("C:\\Users\\路聃\\Desktop\\Java\\Copy["+count+"].java");}BufferedWriter bw = new BufferedWriter(new FileWriter(file));String line;while ((line= br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}} catch (IOException e) {e.printStackTrace();}}
}

依然显示连接失败。。。