网络编程（TCP协议）

本文主要是介绍网络编程（TCP协议），对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

TCP协议发送数据

A：创建Socket对象---利用Socket对象

B：获取输出流，写数据

C：释放资源

package Day26;

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

/*
 * TCP协议发送数据：
 * A:创建发送端的Socket对象
 *         这一步如果成功，就说明连接已经建立成功了。
 * B:获取输出流，写数据
 * C:释放资源
 *
 * 连接被拒绝。TCP协议一定要先看服务器。
 * java.net.ConnectException: Connection refused: connect
 */
public class TcpDemo {
    public static void main(String[] args) throws IOException {
        //创建Socket对象
        // Socket(InetAddress address, int port)
        //Socket s = new Socket(InetAddress.getByName("192.168.12.92"), 8888);
        //public Socket(String host,int port)
        // ----创建一个流套接字并将其连接到指定主机上的指定端口号。
        //指定IP地址和连接端口
        Socket sk = new Socket("192.168.1.8",12345);

        //获取输出流，写数据
        //OutputStream getOutputStream()------返回此套接字的输出流。
        //此抽象类是表示输出字节流的所有类的超类。输出流接受输出字节并将这些字节发送到某个接收器。
        //获取输出流
        OutputStream os = sk.getOutputStream();
        //写数据-----将字符数据转换为字节数组，写入
        os.write("你好中国".getBytes());

        //释放资源
        sk.close();
    }
}

 TCP协议接受数据

A:创建Socket接受对象

B：监听客户端连接--返回一个对应的Socket对象

C：获取输入流，读取数据并将其显示在控制台

D:释放资源

package Day26;

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

// * TCP协议接收数据：
// * A:创建接收端的Socket对象
// * B:监听客户端连接。返回一个对应的Socket对象
// * C:获取输入流，读取数据显示在控制台
// * D:释放资源
// */
public class ServersDemo {
    public static void main(String[] args) throws IOException {
        //创建Socket接收对象---并给出连接的端口
        //public ServerSocket(int port)-------创建绑定到特定端口的服务器套接字
        ServerSocket ss = new ServerSocket(12345);

        //监听客户端连接，返回一个对应的Socket对象
        //public Socket accept()----侦听并接受到此套接字的连接---返回新的套接字
        Socket st = ss.accept();

        //获取输入流和读出数据显示到控制台
        //获取输入流对象
        //public InputStream getInputStream()---从此套接字读取字节的输入流。
        InputStream  is = st.getInputStream();

        //读出数据
        byte [] bt = new byte[1024];
        //public int read(byte[] b)
        //从输入流中读取一定数量的字节，并将其存储在缓冲区数组 b 中
        int len =  is.read(bt);
        //public String(byte[] bytes,int offset,int length)---将字节数组转换为字符串
        String aa = new String(bt,0,len);

        //获取发送端的ip地址
        String ip = st.getInetAddress().getHostAddress();

        //输出到控制台
        System.out.println(ip+"--"+aa);

        //释放资源
        st.close();
        //ss.close();---服务器不应该关闭



    }
}

 服务器给客户端一个反馈的案例

Tcp客户端

package cn.itcast_07;

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Socket对象
        Socket s = new Socket("192.168.12.92", 9999);

        // 获取输出流
        OutputStream os = s.getOutputStream();
        os.write("今天天气很好,适合睡觉".getBytes());

        // 获取输入流
        InputStream is = s.getInputStream();
        byte[] bys = new byte[1024];
        int len = is.read(bys);// 阻塞
        String client = new String(bys, 0, len);
        System.out.println("client:" + client);

        // 释放资源
        s.close();
    }
}

TCP协议服务器

    package cn.itcast_07;

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 {
        // 创建服务器Socket对象
        ServerSocket ss = new ServerSocket(9999);

        // 监听客户端的连接
        Socket s = ss.accept(); // 阻塞

        // 获取输入流
        InputStream is = s.getInputStream();
        byte[] bys = new byte[1024];
        int len = is.read(bys); // 阻塞
        String server = new String(bys, 0, len);
        System.out.println("server:" + server);

        // 获取输出流
        OutputStream os = s.getOutputStream();
        os.write("数据已经收到".getBytes());

        // 释放资源
        s.close();
        // ss.close();
    }
}

* 客户端键盘录入，服务器输出到控制台

客户端：

package cn.itcast_08;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;

/*
 * 客户端键盘录入，服务器输出到控制台
 */
public class ClientDemo {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 22222);

        // 键盘录入数据
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        // 把通道内的流给包装一下
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) {
            // 键盘录入数据要自定义结束标记
            if ("886".equals(line)) {
                break;
            }
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        // 释放资源
        // bw.close();
        // br.close();
        s.close();
    }
}

服务器：

package cn.itcast_08;

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(22222);

        // 监听客户端连接
        Socket s = ss.accept();

        // 包装通道内容的流
        BufferedReader br = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        String line = null;
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }

        // br.close();
        s.close();
        // ss.close();
    }
}

客户端键盘录入，服务器输出文本文件

package cn.itcast_09;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;

/*
 * 客户端键盘录入，服务器输出文本文件
 */
public class ClientDemo {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 23456);

        // 封装键盘录入
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        // 封装通道内的数据
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) {
            if ("over".equals(line)) {
                break;
            }

            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        // bw.close();
        // br.close();
        s.close();
    }
}

接受数据

package cn.itcast_09;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
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(23456);

        // 监听客户端连接
        Socket s = ss.accept();

        // 封装通道内的数据
        BufferedReader br = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        // 封装文本文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("a.txt"));

        String line = null;
        while ((line = br.readLine()) != null) {
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        bw.close();
        // br.close();
        s.close();
        // ss.close();
    }
}

 客户端文本文件，服务器输出到控制台

客户端

package cn.itcast_10;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.Socket;

/*
 * 客户端文本文件，服务器输出到控制台
 */
public class ClientDemo {
    public static void main(String[] args) throws IOException {
        // 创建Socket对象
        Socket s = new Socket("192.168.12.92", 34567);

        // 封装文本文件
        BufferedReader br = new BufferedReader(new FileReader(
                "InetAddressDemo.java"));
        // 封装通道内的流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) {
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        br.close();
        s.close();
    }
}

服务器

package cn.itcast_10;

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(34567);

        // 监听客户端连接
        Socket s = ss.accept();

        // 封装通道内的流
        BufferedReader br = new BufferedReader(new InputStreamReader(
                s.getInputStream()));

        String line = null;
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }

        
        s.close();
    }
}

TCP协议上传文本文件----字符流

客户端

package cn.itcast_11;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.Socket;

public class UploadClient {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 11111);

        // 封装文本文件
        BufferedReader br = new BufferedReader(new FileReader(
                "InetAddressDemo.java"));
        // 封装通道内流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) {
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        // 释放资源
        br.close();
        s.close();
    }
}

服务器端

package cn.itcast_11;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class UploadServer {
    public static void main(String[] args) throws IOException {
        // 创建服务器端的Socket对象
        ServerSocket ss = new ServerSocket(11111);

        // 监听客户端连接
        Socket s = ss.accept();

        // 封装通道内的流
        BufferedReader br = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        // 封装文本文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("Copy.java"));

        String line = null;
        while ((line = br.readLine()) != null) {
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        bw.close();
        s.close();
    }
}

TCP协议上传文本文件并给出反馈信息----字符流

客户端

package cn.itcast_12;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;

/*
 * 按照我们正常的思路加入反馈信息，结果却没反应。为什么呢?
 * 读取文本文件是可以以null作为结束信息的，但是呢，通道内是不能这样结束信息的。
 * 所以，服务器根本就不知道你结束了。而你还想服务器给你反馈。所以，就相互等待了。
 * 
 * 如何解决呢?
 * A:在多写一条数据，告诉服务器，读取到这条数据说明我就结束，你也结束吧。
 *         这样做可以解决问题，但是不好。
 * B:Socket对象提供了一种解决方案
 *         public void shutdownOutput()
 */

public class UploadClient {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 11111);

        // 封装文本文件
        BufferedReader br = new BufferedReader(new FileReader(
                "InetAddressDemo.java"));
        // 封装通道内流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) { // 阻塞
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        
        //自定义一个结束标记
//        bw.write("over");
//        bw.newLine();
//        bw.flush();
        
        //Socket提供了一个终止，它会通知服务器你别等了，我没有数据过来了
        s.shutdownOutput();

        // 接收反馈
        BufferedReader brClient = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        String client = brClient.readLine(); // 阻塞
        System.out.println(client);

        // 释放资源
        br.close();
        s.close();
    }
}

 服务器

package cn.itcast_12;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class UploadServer {
    public static void main(String[] args) throws IOException {
        // 创建服务器端的Socket对象
        ServerSocket ss = new ServerSocket(11111);

        // 监听客户端连接
        Socket s = ss.accept();// 阻塞

        // 封装通道内的流
        BufferedReader br = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        // 封装文本文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("Copy.java"));

        String line = null;
        while ((line = br.readLine()) != null) { // 阻塞
        // if("over".equals(line)){
        // break;
        // }
            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();

        // 释放资源
        bw.close();
        s.close();
    }
}

TCP协议上传图片 ----采用字节流

客户端

A: OutputStream------

public void flush()
           throws IOException

刷新此输出流并强制写出所有缓冲的输出字节

package cn.itcast_13;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;

public class UploadClient {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 19191);

        // 封装图片文件
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
                "林青霞.jpg"));
        // 封装通道内的流
        BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());

        byte[] bys = new byte[1024];
        int len = 0;
        while ((len = bis.read(bys)) != -1) {
            bos.write(bys, 0, len);
            bos.flush();
        }
        
        s.shutdownOutput();

        // 读取反馈
        InputStream is = s.getInputStream();
        byte[] bys2 = new byte[1024];
        int len2 = is.read(bys2);
        String client = new String(bys2, 0, len2);
        System.out.println(client);

        // 释放资源
        bis.close();
        s.close();
    }
}

 服务器端

A: OutputStream------

public void flush()
           throws IOException

刷新此输出流并强制写出所有缓冲的输出字节

package cn.itcast_13;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class UploadServer {
    public static void main(String[] args) throws IOException {
        // 创建服务器Socket对象
        ServerSocket ss = new ServerSocket(19191);

        // 监听客户端连接
        Socket s = ss.accept();

        // 封装通道内流
        BufferedInputStream bis = new BufferedInputStream(s.getInputStream());
        // 封装图片文件
        BufferedOutputStream bos = new BufferedOutputStream(
                new FileOutputStream("mn.jpg"));

        byte[] bys = new byte[1024];
        int len = 0;
        while ((len = bis.read(bys)) != -1) {
            bos.write(bys, 0, len);
            bos.flush();
        }

        // 给一个反馈
        OutputStream os = s.getOutputStream();
        os.write("图片上传成功".getBytes());

        bos.close();
        s.close();
    }
}

 TCP多线程改进多个客户端上传文件

客户端

package cn.itcast_15;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;

public class UploadClient {
    public static void main(String[] args) throws IOException {
        // 创建客户端Socket对象
        Socket s = new Socket("192.168.12.92", 11111);

        // 封装文本文件
        // BufferedReader br = new BufferedReader(new FileReader(
        // "InetAddressDemo.java"));
        BufferedReader br = new BufferedReader(new FileReader(
                "ReceiveDemo.java"));
        // 封装通道内流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                s.getOutputStream()));

        String line = null;
        while ((line = br.readLine()) != null) { // 阻塞
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        // Socket提供了一个终止，它会通知服务器你别等了，我没有数据过来了
        s.shutdownOutput();

        // 接收反馈
        BufferedReader brClient = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        String client = brClient.readLine(); // 阻塞
        System.out.println(client);

        // 释放资源
        br.close();
        s.close();
    }
}

多线程 

package cn.itcast_15;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;

public class UserThread implements Runnable {
    private Socket s;

    public UserThread(Socket s) {
        this.s = s;
    }

    @Override
    public void run() {
        try {
            // 封装通道内的流
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    s.getInputStream()));
            // 封装文本文件
            // BufferedWriter bw = new BufferedWriter(new
            // FileWriter("Copy.java"));

            // 为了防止名称冲突
            String newName = System.currentTimeMillis() + ".java";
            BufferedWriter bw = new BufferedWriter(new FileWriter(newName));

            String line = null;
            while ((line = br.readLine()) != null) { // 阻塞
                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();

            // 释放资源
            bw.close();
            s.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

 服务器

package cn.itcast_15;

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

public class UploadServer {
    public static void main(String[] args) throws IOException {
        // 创建服务器Socket对象
        ServerSocket ss = new ServerSocket(11111);

        while (true) {
            Socket s = ss.accept();
            new Thread(new UserThread(s)).start();
        }
    }
}

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