java网络编程

一：基于tcp的网络通信`

在这里插入代码片

/*服务器*/
package com.yxy;

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

public class TestServer {

    /*服务器端*/
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket=new ServerSocket(8888);
        Socket socket = serverSocket.accept();
        InputStream inputStream = socket.getInputStream();
        DataInputStream dataInputStream=new DataInputStream(inputStream);
        String s = dataInputStream.readUTF();
        System.out.println("客户端说："+s);

        OutputStream outputStream=socket.getOutputStream();
        DataOutputStream dataOutputStream=new DataOutputStream(outputStream);
        String s1="你好我是服务器";
        dataOutputStream.writeUTF(s1);
        dataOutputStream.close();
        dataInputStream.close();
        socket.close();
        serverSocket.close();
    }
}

/*客户端*/

package com.yxy;

import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;

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

public class TestClient {
    /*客户端*/
    public static void main(String[] args) throws IOException {
        Socket socket=new Socket("192.168.0.103",8888);
        OutputStream outputStream = socket.getOutputStream();
        DataOutputStream dataOutputStream=new DataOutputStream(outputStream);
        dataOutputStream.writeUTF("你好，我是客户端");


        InputStream inputStream = socket.getInputStream();
        DataInputStream dataInputStream=new DataInputStream(inputStream);
        String s = dataInputStream.readUTF();
        System.out.println("服务器返回消息"+s);
        dataOutputStream.close();
        dataInputStream.close();
        socket.close();

    }
}

上面代码存在一个很严重的问题，服务器只能监听一次，那怎么可以解决了，在这了我提供一种方法，利用多线程，并且在上面增加一个简单的登录功能。这里没有连接数据

/*User*/
package com.yxy;

import java.io.Serializable;

public class User implements Serializable {
    private String username;
    private String password;

    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

/*服务器线程*/
package com.yxy;

import jdk.internal.util.xml.impl.Input;

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

public class ServerThread extends Thread{
    Socket socket=null;
    InputStream inputStream=null;
    ObjectInputStream objectInputStream=null;
    DataOutputStream dataOutputStream=null;
    OutputStream outputStream=null;
    public ServerThread(Socket socket){
        this.socket = socket;
    }
    @Override
    public void run() {
        try {
            inputStream = socket.getInputStream();
            User user = (User) objectInputStream.readObject();
            boolean flag = false;
            if(user.getUsername().equals("yzy")&&user.getPassword().equals("1130")){
                flag = true;
            }

            outputStream=socket.getOutputStream();
            dataOutputStream=new DataOutputStream(outputStream);
            dataOutputStream.writeBoolean(flag);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }finally {
            try {
                if(dataOutputStream!=null){
                    dataOutputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(outputStream!=null){
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(objectInputStream!=null){
                    objectInputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(inputStream!=null){
                    inputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}
/*服务器*/
package com.yxy;

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

public class TestServer {

    public static void main(String[] args) {
        System.out.println("服务器启动了");
        //1.创建套接字： 指定服务器的端口号
        ServerSocket serverSocket= null;
        Socket socket = null;
        int count=0;
        try {
            serverSocket=new ServerSocket(8888);
            socket=serverSocket.accept();
            new ServerThread(socket).start();
            count++;
            /*输出客户端信息*/
            System.out.println("当前是第"+count+"个用户访问我们的服务器,对应的用户是："+socket.getInetAddress());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}
/*客户端*/
package com.yxy;

import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;

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

public class TestClient {
    /*客户端*/
    public static void main(String[] args) throws IOException {
        Scanner scanner=new Scanner(System.in);
        System.out.println("请输入username:");
        String username = scanner.next();
        System.out.println("请输入password:");
        String password = scanner.next();
        Socket socket=new Socket("192.168.0.103",8888);
        OutputStream outputStream = socket.getOutputStream();
        User user =new User(username,password);
        ObjectOutputStream objectOutputStream=new ObjectOutputStream(outputStream);
        objectOutputStream.writeObject(user);



        InputStream inputStream=socket.getInputStream();
        DataInputStream dataInputStream=new DataInputStream(inputStream);
        boolean b = dataInputStream.readBoolean();
        if (b){
            System.out.println("登陆成功");
        }else{
            System.out.println("登录失败");
        }
        dataInputStream.close();
        inputStream.close();
        objectOutputStream.close();
        outputStream.close();
        socket.close();

    }
}

明天分享udp的一些基础知识，如果有什么不懂可以随时私信