Java 网络编程（大全）（上）

package bao;
import java.net.InetAddress;
public class Test {
    public static void main(String[] args) throws Exception {
        //1.获取本机地址ip对象
        InetAddress ip1 = InetAddress.getLocalHost();
        System.out.println(ip1.getHostName());//获取主机名字
        System.out.println(ip1.getHostAddress());//获取ip地址
        //2.获取域名ip对象
        InetAddress ip2 = InetAddress.getByName("www.baidu.com");
        System.out.println(ip2.getHostName());//获取域名
        System.out.println(ip2.getHostAddress());//获取域名的ip地址
        //3.获取公网对象
        InetAddress ip3 = InetAddress.getByName("112.80.248.76");
        System.out.println(ip3.getHostName());//获取公网名字
        System.out.println(ip3.getHostAddress());//获取公网ip地址
        //判断网络是否能连接通信 ping 5s之前测试是否能通过
        System.out.println(ip3.isReachable(5000));//通过会返回true
    }
}

package bao;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
//发送端
public class Test {
    public static void main(String[] args) throws IOException {
        System.out.println("==============客户端启动===============");
        //1.创建发送通信管道
        Socket socket = new Socket("127.0.0.1",7777);//参数一：服务端地址 参数二：服务端端口
        //2.从scoket管道中获得一个字节输出流,负责发送数据
        OutputStream os = socket.getOutputStream();
        //3.字节流升级成打印流
        PrintStream ps = new PrintStream(os);
        //4.发送消息
        ps.println("大哥，我来了");
        ps.flush();//刷新
    }
}

package bao;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
//服务端
public class Test1 {
    public static void main(String[] args) throws IOException {
        System.out.println("========服务端启动============");
        //1.创建接收管道，注册端口
        ServerSocket serverSocket = new ServerSocket(7777);//参数一：定义服务端口
        //2.等待管道连接
        Socket accept = serverSocket.accept();
        //3.从管道中获取一个字节输入流
        InputStream is = accept.getInputStream();
        //4.字节流升级生缓冲输入流
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        //5.按照行读取消息会更好
        String a;
        if ((a = br.readLine())!=null){
            System.out.println(accept.getRemoteSocketAddress()+"说了："+a);
        }
    }
}

package bao;
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner;
public class kehu {
    public static void main(String[] args) throws Exception {
        System.out.println("客户端启动");
        //1.创建与服务端连接的管道
        Socket s = new Socket(InetAddress.getLocalHost(), 9966);
        //2.创建一个线程负责客户端的消息读取
        new ClientReaderThread(s).start();
        //3.创建一个字节输入流管道
        OutputStream o = s.getOutputStream();
        PrintStream p = new PrintStream(o);//升级流
        //4.客户端输入数据
        Scanner sc = new Scanner(System.in);
        while (true){
            System.out.println("请输入：");
            String s1 = sc.nextLine();
            p.println(s1);//发送数据出去
            p.flush();//刷新流
        }
    }
}
class ClientReaderThread extends Thread{
    private Socket socket;
    public ClientReaderThread(Socket socket){
        this.socket = socket;
    }
        @Override
        public void run(){
            try {
                //把字节输入流包装成字符输入流
                InputStream i = socket.getInputStream();
                BufferedReader b = new BufferedReader(new InputStreamReader(i));
                String s1;
                while (true){
                    if ((s1=b.readLine())!=null){
                        System.out.println("收到了消息"+s1);
                    }
                }
            } catch (IOException e) {
                System.out.println("服务器把你提出群聊");
            }
        }
    }

package bao;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
public class fuwu {
    //1.定义一个静态变量储存全部管道
    public static List<Socket> all_Sockets = new ArrayList<>();
    public static void main(String[] args) throws IOException {
        System.out.println("服务端启动成功");
        //2.服务端口注册
        ServerSocket ss = new ServerSocket(9966);
        //3.管道死循环设置
        while (true){
            Socket s = ss.accept();
            System.out.println(s.getRemoteSocketAddress()+"上线了");
            all_Sockets.add(s);
            new fuwuThread(s).start();
        }
    }
}
class fuwuThread extends Thread{
    private Socket socket;
    public fuwuThread(Socket socket){
        this.socket=socket;
    }
    @Override
    public void run(){
        try {
            InputStream i = socket.getInputStream();
            BufferedReader b = new BufferedReader(new InputStreamReader(i));
            String s1;
            while ((s1=b.readLine())!=null){
                System.out.println(socket.getRemoteSocketAddress()+"说"+s1);
                sendMessage(s1);
            }
        } catch (IOException e) {
            System.out.println(socket.getRemoteSocketAddress()+"离线了");
            fuwu.all_Sockets.remove(socket);
        }
    }
    private void sendMessage (String s1) throws IOException {
        for (Socket s:fuwu.all_Sockets){
            OutputStream o = s.getOutputStream();
            PrintStream p = new PrintStream(o);
            p.println(s1);
            p.flush();
        }
    }
}