java网络编程 客户端和服务器端

1.服务器端

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

public class HelloWorldServer {

public static void main(String[] args) {
ServerSocket server = null;
BufferedReader reader = null;
Socket client = null;
try {
server = new ServerSocket(9000);//创建ServerSocket对象，并绑定端口
client = server.accept();//调用accept方法，等待客户端的连接
InputStream in = client.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
String str = reader.readLine();
System.out.println(str);
} catch (IOException e) {
e.printStackTrace();
}finally{
try{
if(client!=null){
client.close();
}
}catch(IOException e){
e.printStackTrace();
}
}
}

}
2.客户端
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;

public class HelloWorldClient {

public static void main(String[] args) {
Socket client = null;
PrintWriter writer = null;
try {
client = new Socket("127.0.0.1", 9000);
OutputStream out = client.getOutputStream();
writer = new PrintWriter(out);
Scanner sc=new Scanner(System.in);
String aa=sc.nextLine();
writer.print(aa);
writer.flush();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally{
try{
if(writer!=null){
writer.close();
}
if(client!=null){
client.close();
}
}catch(IOException e){
e.printStackTrace();
}
}
}

}

TCP编程

   java.net.Socket

   java.net.ServerSocket

TCP编程的核心思路

   开发服务器端

   ServerSocket ss = new ServerSocket(9000)

   ss.accept();

   Socket s = new Socket("127.0.0.1", 9000)