文章目录

• 网络编程概述
• • 基本概念
  • IP地址概念
  • InetAddress
  • 端口与协议概念
• UDP通信编程
• • UDP发送数据
  • UDP接受数据
  • UDP通信程序练习
• TCP通信编程
• • TCP发送数据
  • TCP接收数据
  • TCP通信程序练习

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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4
        s.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;}

    @Override
    public 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。。。

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