[网络协议]Java基础练习（十五） TCP，URL网络编程

1、使用TCP网络编程，实现图片的下载。

客户端：

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

public class Client {
    public static void main(String[] args) throws IOException {

            Socket socket = new Socket("localhost",8081);

            InputStream inputStream = socket.getInputStream();
            FileOutputStream fileOutputStream = new FileOutputStream("src\\ParcticeDiwuzhou\\lx0811\\lx01\\fileload\\two.jpg");


            byte[] bytes = new byte[1024];
            int read = inputStream.read(bytes);
            while (read!=-1){
                fileOutputStream .write(bytes,0,read);
                read = inputStream.read(bytes);
            }


            fileOutputStream.close();
            inputStream.close();
            socket.close();

    }


}

服务端

package ParcticeDiwuzhou.lx0811.lx01.fileload;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8081);
        Socket accept = serverSocket.accept();

        FileInputStream fileInputStream = new FileInputStream("src\\ParcticeDiwuzhou\\lx0811\\lx01\\fileload\\one.jpg");
        OutputStream outputStream = accept.getOutputStream();

        byte[] bytes = new byte[1024];
        int i = fileInputStream.read(bytes);
//        if(i!=-1){图片输出不完全，只读了一次，没有读完，写while循环读取内容，直到读完
        while (i!=-1){
            outputStream.write(bytes,0,i);
            i=fileInputStream.read(bytes);
        }

        outputStream.close();
        fileInputStream.close();

        accept.close();
        serverSocket.close();
    }
}

2、使用URL编程，下载一个网络图片

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;


public class Urlxl {
    public static void main(String[] args) throws IOException {
        // 创建url对象
        URL url = new URL("http://localhost:8080/mypicture/a.jpg");
        //建立连接
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        //下载

        FileOutputStream fileOutputStream =
                new FileOutputStream("src\\ParcticeDiwuzhou\\lx0811\\lx02\\d.jpg");
        InputStream inputStream = httpURLConnection.getInputStream();

        byte[] bytes = new byte[1024];
        int read = inputStream.read(bytes);
        while (read != -1) {
            fileOutputStream.write(bytes, 0, read);
            read = inputStream.read(bytes);
        }

        fileOutputStream.close();
        inputStream.close();

        //关闭连接
        httpURLConnection.disconnect();
    }
}

3、使用TCP网络编程，完成注册功能

客户端：
填写用户信息
发送信息给服务器

服务器：
接收信息
保存新用户到user.txt中

用户信息类

import com.sun.org.apache.xml.internal.serialize.Serializer;

import java.io.Serializable;

public class User implements Serializable {
    
    public User() {
    }

    public User(String name, int id) {
        this.name = name;
        this.id = id;
    }

    private  String name;
    private int id;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", id=" + id +
                '}';
    }
}

客户端

import java.io.*;
import java.net.Socket;
import java.util.Scanner;

public class Client {
    public static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException, ClassNotFoundException {
        while (true) {//使用while不断循环
            System.out.println("添加");
            tcpIo();
        }
    }

    public static User addUser() {
        System.out.println("请输入用户名");
        String next = scanner.next();
        System.out.println("请输入ID");
        int id = scanner.nextInt();
        User user = new User(next, id);
        return user;
    }

//    public static void  xulehua() throws IOException {
//        FileOutputStream fileOutputStream = new FileOutputStream("src\\ParcticeDiwuzhou\\lx0811\\lx03\\localfile",true);
//        ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream);
        addUser();         //获取方法返回值就是调用方法执行一次然后返回一个值
//
//        objectOutputStream.writeObject(addUser());
        System.out.println(addUser().toString());  //因为调用该方法输入了一次
//    }

    public static void tcpIo() throws IOException, ClassNotFoundException {
        //xulehua();
//        System.out.println("111111");   判断程序是否执行到此,也可添加断点
        Socket socket = new Socket("localhost", 8820);

//        FileInputStream fileInputStream = new FileInputStream("src\\ParcticeDiwuzhou\\lx0811\\lx03\\localfile");
//        ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);

        OutputStream outputStream = socket.getOutputStream();

         ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
//        User user=(User) objectInputStream.readObject(); 注册在客户端读什么？

        //不使用序列化，传输字符串
//        String s = addUser().toString();
//
//        outputStream.write(s.getBytes());

        objectOutputStream.writeObject(addUser());

        objectOutputStream.close();
        outputStream.close();
        socket.close();
    }
}

服务端

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

public class Service {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        while (true) {
            ServerSocket serverSocket = new ServerSocket(8820);
            Socket accept = serverSocket.accept();

            //序列化流读取传入的对象
            InputStream inputStream = accept.getInputStream();
            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);



            FileOutputStream fileOutputStream =
                    new FileOutputStream("src\\ParcticeDiwuzhou\\lx0811\\lx03\\User.txt", true);



           // byte[] bytes = new byte[1024];
           // int read = inputStream.read(bytes);

//            while (read != -1) {
//                fileOutputStream.write(bytes, 0, read);
//                read = inputStream.read(bytes);
//            }

            //将读取的对象转为字符串输出
            User user=(User) objectInputStream.readObject();
            while (user !=null){
                fileOutputStream.write(user.toString().getBytes());
                user=(User) objectInputStream.readObject();
            }

            
            fileOutputStream.close();
            objectInputStream.close();
            inputStream.close();
            accept.close();
            serverSocket.close();
        }
    }
}