Java网络编程一

1.InetAddress的应用

import java.util.List;
import java.math.BigDecimal;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;

import javax.naming.spi.DirStateFactory.Result;

import org.omg.PortableInterceptor.DISCARDING;

import java.util.Map;
import java.util.Queue;
/**
 * InetAddress类
 * @author 16114
 *
 */
public class Main{
    public static void main(String[] args) {
        try {
            InetAddress address = InetAddress.getLocalHost();
            System.out.println("计算机名：" + address.getHostName());
            System.out.println("IP地址：" + address.getHostAddress());
            byte[] bytes = address.getAddress();
            System.out.println("字节数组形式的IP：" + Arrays.toString(bytes));
            System.out.println(address);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        try {
            InetAddress address2 = InetAddress.getByName("Roni");
            System.out.println(address2.getHostName());
            System.out.println(address2.getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        
        
    }
}

 2.URL

import java.util.List;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigDecimal;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;

import javax.naming.spi.DirStateFactory.Result;

import org.omg.PortableInterceptor.DISCARDING;

import java.util.Map;
import java.util.Queue;
/**
 * URL类
 * @author 16114
 *
 */
public class Main{
    public static void main(String[] args) {
        
        try {
            URL url = new URL("http://www.baidu.com");
            try {
                InputStream is = url.openStream();
                InputStreamReader isr = new InputStreamReader(is,"utf-8");
                BufferedReader br = new BufferedReader(isr);
                String data = br.readLine();
                while(data!=null) {
                    System.out.println(data);
                    data=br.readLine();
                }
                br.close();
                isr.close();
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
                
            }
            
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        
    }
}

 3.客户端向服务器端的通信

Server

package com.zrl.thread;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

/**
 * 基于TCP协议的Socket协议
 * 服务端
 * @author 16114
 *
 */
public class Server {
    public static void main(String[] args) {
        //1.创建一个服务器端Socket，即ServerSocket，指定绑定的端口
        try {
            ServerSocket serverSocket = new  ServerSocket(8888);
            //2.调用accept（）方法开始监听，等待客户端的连接
            System.out.println("***服务器即将启动，等待客户端的链接***");
            Socket socket = serverSocket.accept();
            //3.获取输入流，并读取客户端信息
            InputStream is = socket.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String info = null;
            while((info=br.readLine())!=null) {
                System.out.println("我是服务器，客户端说：" + info);
            }
            socket.shutdownInput();
            //4.关闭相关资源
            br.close();
            isr.close();
            is.close();
            socket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Client

package com.zrl.thread;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {
    public static void main(String[] args) {
        //1.创建客户端Socket，指定服务器端地址和端口
        Socket socket;
        try {
            socket = new Socket("localhost", 8888);
            //2.获取输出流，向服务器发送消息
            OutputStream os = socket.getOutputStream();
            PrintWriter pw = new PrintWriter(os);//将输出流包装为打印流
            pw.write("用户名：admin;密码:123");
            pw.flush();
            socket.shutdownInput();
            //3.关闭资源
            pw.close();
            os.close();
            socket.close();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
}

 一个服务端，多个客户端

Server.java

package com.zrl.thread;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

/**
 * 基于TCP协议的Socket协议
 * 服务端
 * @author 16114
 *
 */

public class Server {
    public static void main(String[] args) {
        //1.创建一个服务器端Socket，即ServerSocket，指定绑定的端口
        try {
            ServerSocket serverSocket = new  ServerSocket(8888);
            //2.调用accept（）方法开始监听，等待客户端的连接
            System.out.println("***服务器即将启动，等待客户端的链接***");
            Socket socket = null;
            //记录客户端的数量
            int cnt = 0;
            //循环监听等待客户端的连接
            while(true) {
                //调用accept（）方法开始监听，等待客户端的连接
                socket = serverSocket.accept();
                //创建一个新线程
                ServerThread serverThread = new ServerThread(socket);
                //启动线程
                serverThread.start();
                cnt++;
                System.out.println("客户端的数量：" + cnt);
                InetAddress address = socket.getInetAddress();
                System.out.println("当前客户端的IP：" + address.getHostAddress());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Client.java

package com.zrl.thread;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {
    public static void main(String[] args) {
        //1.创建客户端Socket，指定服务器端地址和端口
        Socket socket;
        try {
            socket = new Socket("localhost", 8888);
            //2.获取输出流，向服务器发送消息
            OutputStream os = socket.getOutputStream();
            PrintWriter pw = new PrintWriter(os);//将输出流包装为打印流
            pw.write("用户名：admin; 密码:456");
            pw.flush();
            socket.shutdownOutput();
            //3.获取输入流并且读取服务器端的响应信息
            InputStream is = socket.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String info = null;
            while((info=br.readLine())!=null) {
                System.out.println("我是客户端，服务端说：" + info);
            }
            //4.关闭资源
            br.close();
            is.close();
            pw.close();
            os.close();
            socket.close();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
}

ServerThread.java

package com.zrl.thread;
/**
 * 服务器端线程处理类
 * @author 16114
 *
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;

public class ServerThread extends Thread {
    //和本线程相关的Socket
    Socket socket = null;
    public ServerThread(Socket socket) {
        this.socket = socket;
    }
    //线程执行的操作，响应客户端的请求
    @Override
    public void run() {
        //获取输入流，并读取客户端信息
        InputStream is=null;
        InputStreamReader isr=null;
        BufferedReader br=null;
        OutputStream os =null;
        PrintWriter pw = null;
        try {
            is = socket.getInputStream();
            isr = new InputStreamReader(is);
            br = new BufferedReader(isr);
            String info = null;
            while((info=br.readLine())!=null) {
                System.out.println("我是服务器，客户端说：" + info);
            }
            socket.shutdownInput();
            //获取输出流，响应客户端的请求
            os = socket.getOutputStream();
            pw = new PrintWriter(os); //包装为打印流
            pw.write("欢迎您！");
            pw.flush(); //调用flush将缓冲输出
            
        } catch (IOException e) {
            e.printStackTrace();
        }finally {//关闭相关资源
                try {
                    if(pw!=null) pw.close();
                    if(os!=null) os.close();
                    if(br!=null) br.close();
                    if(isr!=null) isr.close();
                    if(is!=null) is.close();
                    if(socket!=null) socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
          }
    }
}
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原文地址：https://www.cnblogs.com/Roni-i/p/9788983.html