网络编程-TCP

1,入门例子

package javaBase.net.tcp;
import java.io.*;
import java.net.*;

/*
 * 客户端client对应的对象是socket，
 * 在该对象建立时就能指定主机，tcp是面向连接的，所以在建立Socket服务时就要有服务端存在
 */
class TcpClient {
	public static void main(String[] args) throws Exception {
		//1,创建客户端socket服务，并指定服务器端主机和端口
		Socket s = new Socket("127.0.0.1",10003);
		//2,为了发送数据，拿到socket中的输出流并写数据
		OutputStream out = s.getOutputStream();
		out.write("tcp client send....".getBytes());
		//3，关闭socket
		s.close();
	}
}
/*
 * 服务端serversocket  自己不创建socket，从客户端获取其socket
 */
public class TcpServer {
	public static void main(String[] args) throws Exception{
		//1,创建服务端的socket服务，Serversocket();并监听一个端口
		ServerSocket ss = new ServerSocket(10003);
		//2,获取客户端传来的对象，accept(),阻塞方法，等待
		Socket s = ss.accept();
		String ip = s.getInetAddress().getHostAddress();//获取客户端ip
		//3,用客户端对象的读取流获取客户端的数据
		InputStream in = s.getInputStream();
		byte [] buf = new byte[1024];
		int len = in.read(buf);
		String data = new String(buf,0,len);
		System.out.println(ip+": "+data );
		//4,关闭客户端
		s.close();
//		ss.close();//服务器一般都不关
	}
}

一次交互，客户端发送，服务端接收，再发送，客户端接收

package javaBase.net.tcp;
import java.io.*;
import java.net.*;

class TcpClient2 {
	public static void main(String[] args) throws Exception {
		Socket s = new Socket("127.0.0.1",10005);
		OutputStream out = s.getOutputStream();
		out.write("服务器，你好，我是客户端".getBytes());
		
		//读取服务端发的数据
		InputStream in  = s.getInputStream();
		byte[] buf = new byte[1024];
		int len = in.read(buf);//阻塞方法，等待服务端数据
		System.out.println("服务器说："+new String(buf,0,len));
		s.close();
	}
}
public class TcpServer2 {
	public static void main(String[] args) throws Exception {
		ServerSocket ss = new ServerSocket(10005);
		Socket s = ss.accept();
		String ip = s.getInetAddress().getHostAddress();
		System.out.println("客户端，你的IP是："+ip);
		InputStream in = s.getInputStream();
		byte[] buf = new byte[1024];
		int len = in.read(buf);
		System.out.println("你刚才说："+new String(buf,0,len)+"我睡4秒钟");
		Thread.sleep(4000);
		OutputStream out = s.getOutputStream();
		out.write("hello,我说这句话你听到没".getBytes());
		s.close();
		
	}
}

服务端开启服务：将客户端的每一行字符转成大写返回

package javaBase.net.tcp;
import java.io.*;
import java.net.*;

class TcpClient3 {
	public static void main(String[] args) throws Exception {
		Socket s = new Socket("127.0.0.1",10006);
		//键盘输入
		BufferedReader in =
				new BufferedReader(new InputStreamReader(System.in));
		//网络输出
		PrintWriter pw = 
				new PrintWriter(s.getOutputStream(),true);
		//网络输入
		BufferedReader bufIn = 
				new BufferedReader(new InputStreamReader(s.getInputStream()	));
		//循环获取键盘录入
		String line = null;
		while((line = in.readLine())!=null){
			if("over".equals(line))
				break;
			pw.println(line);//PrintWriter设为true,这里自动flush（），println（）带回车符，write（）不带
			
			//获取服务端返回的大写数据
			String str = bufIn.readLine();
			System.out.println("server:"+str);
		}
		in.close();//键盘录入不属于socket，自己关
		s.close();
		
	}
}
public class TcpServer3 {
	public static void main(String[] args) throws Exception {
		ServerSocket ss = new ServerSocket(10006);
		Socket s =  ss.accept();
		String ip = s.getInetAddress().getHostAddress();
		System.out.println(ip+"...connected");
		//读取客户端流
		BufferedReader in = 
				new BufferedReader(new InputStreamReader(s.getInputStream()));
		//返回给客户端流
		PrintWriter pw = 
				new PrintWriter(s.getOutputStream(),true);
		//读取客户端数据
		String line = null;
		while((line = in.readLine())!=null){
			pw.println(line.toUpperCase());
		}
		s.close();
//		ss.close();
		
	}
}

多客户端并发上传图片到服务器端

package javaBase.net.tcp;
import java.io.*;
import java.net.*;
/*
 * 客户端上传图片到服务器端
 */
class PicClient {
	public static void main(String[] args) throws Exception{
		Socket s= new Socket("127.0.0.1",10007);
		FileInputStream fin = new FileInputStream("man.jpg");
		OutputStream out = s.getOutputStream();
		//读写
		byte[] buf = new byte[1024];
		int len = 0;
		while((len = fin.read(buf))!=-1){
			out.write(buf,0,len);
		}
		s.shutdownOutput();
		//接收服务器端返回数据
		InputStream in = s.getInputStream();
		byte[] bufIn = new byte[1024];
		int num = in.read(bufIn);
		System.out.println(new String(bufIn,0,num));
		fin.close();
		s.close();
	}
}
/**
 * 服务器端并发上传图片
 * @author xukunn
 *	多线程
 */
class PicThread implements Runnable{
	private Socket s;
	public PicThread(Socket s) {
		this.s = s;
	}
	@Override
	public void run() {
		try {
			String ip = s.getInetAddress().getHostAddress();
			System.out.println(ip+"....connected");
			int count =1;
			File file = new File("man_server"+"("+count+")" +".jpg");
			while(file.exists()){
				file = new File("man_server"+"("+(count++)+")" +".jpg");
			}
			FileOutputStream fout = new FileOutputStream(file);
			InputStream in = s.getInputStream();
			byte[] buf = new byte[1024];
			int len = 0;
			while((len = in.read(buf))!=-1){
				fout.write(buf,0,len);
			}
			//回应客户端
			OutputStream out = s.getOutputStream();
			out.write("上传成功".getBytes());
			fout.close();
			s.close();
		} catch (Exception e) {
			throw new RuntimeException("上传失败");
		}
		
		
	}
}
/*
 * 这个服务端只能处理一个客户端的请求，另一个客户端只能等第一个客户端上传完成了，才会再次调用accept（）方法
 * 所以服务端最好将每一个客户端封装到一个单独的线程中
 */
public class PicServer {
	public static void main(String[] args) throws Exception{
		ServerSocket ss = new ServerSocket(10007);
		while(true){
			Socket s = ss.accept();
			new Thread(new PicThread(s)).start();
			
		}
		
	}
}