网络编程 TCP

TCP网络编程分为客户端和服务端

客户端使用 Socket类

服务端使用 ServerSocket类

★TCP实现聊天

1.客户端 TcpClientDemo01.java

package com.ckfuture;

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

//客户端
public class TcpClientDemo01 {
    public static void main(String[] args) {

        Socket socket=null;
        OutputStream os=null;
        try {
            //1.要知道服务器地址,端口号
            InetAddress serverIP = InetAddress.getByName("127.0.0.1");
            int port=9999;
            //2.创建一个socket连接
            socket = new Socket(serverIP,port);
            //3.发送消息
            os = socket.getOutputStream();
            os.write("你好，欢迎创客未来".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();
                }
            }
        }
    }
}

2.服务器  TcpServerDemo01.java

package com.ckfuture;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

//服务端
public class TcpServerDemo01 {
    public static void main(String[] args) {
        ServerSocket serverSocket=null;
        Socket socket=null;
        InputStream is=null;
        ByteArrayOutputStream baos=null;
        try {
            //1.我得有一个地址
            serverSocket = new ServerSocket(9999);

            //循环接收连接
            while(true){
                //2.等待客户端连接过来
                socket = serverSocket.accept();
                //3.读取客户端的消息
                is = socket.getInputStream();
                //管道流
                baos = new ByteArrayOutputStream();
                byte[] buffer=new byte[1024];
                int len;
                while((len=is.read(buffer))!=-1){
                    baos.write(buffer,0,len);
                }
                System.out.println("接收消息："+baos.toString());
            }

        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            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();
               }
           }

        }
    }
}

3.依次运行服务端和客户端

 

 4.工作流程

客户端：

　　① 连接服务器 Socket

　　② 发送消息

服务端：

　　① 建立服务的端口 ServerSocket

　　② 等待用户的连接 accept

　　③ 接收用户的消息

 ★ TCP文件上传

1.创建一个客户端用来上传文件流  TcpClientDemo02.java

package com.ckfuture;

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class TcpClientDemo02 {
    public static void main(String[] args) throws Exception {
        //1.创建一个Socket连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9000);
        //2.创建一个输出流
        OutputStream os = socket.getOutputStream();
        //3.读取文件
        FileInputStream fis = new FileInputStream(new File("logo.png"));
        //4.写出文件
        byte[] buffer = new byte[1024];
        int len;
        while ((len=fis.read(buffer))!=-1){
            os.write(buffer,0,len);
        }
        //通知服务器，我已经结束了
        socket.shutdownOutput();//传输完成

        //确定服务器接收完毕，才能够断开连接
        InputStream inputStream = socket.getInputStream();
        //
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer2= new byte[1024];
        int len2;
        while((len2=inputStream.read(buffer2))!=-1){
            baos.write(buffer2,0,len2);
        }
        System.out.println(baos.toString());
        //5.关闭资源
        baos.close();
        inputStream.close();
        fis.close();
        os.close();
        socket.close();
    }
}

2.创建一个服务端用来接收文件流  TcpServerDemo02.java

package com.ckfuture;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServerDemo02 {
    public static void main(String[] args) throws Exception {
        //1.创建一个服务
        ServerSocket serverSocket = new ServerSocket(9000);
        //2.监听客户端的连接
        Socket socket = serverSocket.accept();//阻塞式监听，会一直等待客户端连接
        //3.获取输入流
        InputStream is = socket.getInputStream();
        //4.文件输出
        FileOutputStream fos = new FileOutputStream(new File("receive.png"));
        byte[] buffer = new byte[1024];
        int len;
        while((len=is.read(buffer))!=-1){
            fos.write(buffer,0,len);
        }

        //通知客户端我接收完毕了
        OutputStream os = socket.getOutputStream();
        os.write("我接收完毕了，你可以断开了".getBytes());


        //关闭资源
        fos.close();
        is.close();
        socket.close();
        serverSocket.close();
    }
}

3.依次运行服务端和客户端