InetAddress，UDP, TCP

package hanshi.net;import java.net.*;public class count {	public static void main(String[] args)throws Exception { 		InetAddress ia = InetAddress.getLocalHost();  //获取本地的		print(ia.getHostAddress());		print(ia.getHostName());		InetAddress iad = InetAddress.getByName("www.baidu.com"); //通过名字获取信息，可以是IP名字，也可以是主机名		print(iad.getHostAddress());		print(iad.getHostName());	}	static public void print(Object obj){		System.out.println(obj);	}}//UDP发送端package hanshi.net;import java.io.BufferedReader;import java.io.InputStreamReader;import java.net.*;public class count {	public static void main(String[] args)throws Exception { 		DatagramSocket ds = new DatagramSocket(110);		BufferedReader bufd = new BufferedReader(new InputStreamReader(System.in));		String str = null;		while((str = bufd.readLine())!=null){			if("over".equals(str)){				break;			}			byte[] bt = str.getBytes();			DatagramPacket dp = new DatagramPacket(bt,bt.length,InetAddress.getByName("192.168.109.119"),1000);			ds.send(dp);					}		ds.close();	}	static public void print(Object obj){		System.out.println(obj);	}}//UDP接收端package hanshi.net;import java.net.DatagramPacket;import java.net.DatagramSocket;public class count2 {	public static void main(String[] args)throws Exception {		DatagramSocket ds = new DatagramSocket(1000); //接受端一定要定义一个端口		while(true){			byte[] buf = new byte[1024];			DatagramPacket dg = new DatagramPacket(buf, buf.length);			ds.receive(dg);   //这里是阻塞方法，没接受到数据就会一直处于等待状态			print(dg.getAddress().getHostAddress()+"***"+dg.getAddress().getHostName());  //通过数据包获取Address来进行操作			print(new String(dg.getData(),0,dg.getLength()));   //获取数据流中的数据，要给定数据的长度			print(dg.getPort());   //获取发送端的端口，如果发送端没有指定一个发送端口，这里就会获取到一个系统随机分配的端口		}		                  //接受端口可以是没有关闭的，就想服务器一样	}	static public void print(Object obj){		System.out.println(obj);	}}//TCPpackage hanshi.net;import java.io.OutputStream;import java.net.*;//如果Scoke的建立是没有传入参数的，那么建立后是没有连接的，但是可以通过connect来连接。。。//这个一建立就有一个Scoket流，也就是网络流。。。//一旦流建立成功就可以拿到输入流和输出流。。。//服务端没有流对象，服务端是通过accept来获取客户端的流对象来使用的。。。//服务端不可以关闭自己，但是可以关闭从客户端获取过来的流对象。。。/*客户端结束后服务端也结束的原因是因为，在s.close()之后的意义就是在末尾加上-1来做结束标志，所以在服务端读取到了就是-1，以为结束了就返回null，所以就跳出循环，结束客户端。。。简化代码：printWriter既可以接受字符流，也可以接受字节流。。。*///理论上在Scokert就要抛出异常，如果连接不上就直接处理了啊。。。public class count {	public static void main(String[] args)throws Exception { 		InetAddress ia = InetAddress.getLocalHost();		Socket sk = new Socket(ia.getHostAddress(),1000);		OutputStream os = sk.getOutputStream();		os.write("chenruibing".getBytes());		//os.close();  这一个可以不关闭，当关闭了socket后，依附在这个上面的流就会自动关闭		sk.close();	}	static public void print(Object obj){		System.out.println(obj);	}}package hanshi.net;import java.io.InputStream;import java.net.ServerSocket;import java.net.Socket;public class count2 {	public static void main(String[] args)throws Exception {		ServerSocket ss = new ServerSocket(1000);  //都要监听端口		Socket s = ss.accept();   //这个也是阻塞式方法		print(s.getInetAddress().getHostAddress()+"denglu");		InputStream is = s.getInputStream();		byte[] bt = new byte[1024];		int len = is.read(bt);		print(new String(bt,0,len));		s.close();		ss.close();			}	static public void print(Object obj){		System.out.println(obj);	}}

TCP

class anli{	public static void main (String[] args)throws Exception	{				while(true)		{			Socket s = new Socket("192.168.109.119",12345);			OutputStream os = s.getOutputStream();			//os.write("ni hao ".getBytes());			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));			String line = br.readLine();			os.write(line.getBytes());			InputStream in  = s.getInputStream();			byte[] bt = new byte[1024];			int len = in.read(bt);			System.out.println(new String(bt,0,len));			//br.close();		}		//s.close();	}}class rec {	public static void main (String[] args)throws Exception	{		ServerSocket ss = new ServerSocket(12345);		while(true)		{			Socket s = ss.accept();			String ip = s.getInetAddress().getHostAddress();			//System.out.println(ip+".......connect");			InputStream in = s.getInputStream();			byte[] bt = new byte[1024];			int len = in.read(bt);			System.out.println(new String(bt,0,len));			OutputStream os = s.getOutputStream();			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));			String line = br.readLine();			os.write(line.getBytes());			s.close();			//br.close();		}			}}

/*简化代码：printWriter既可以接受字符流，也可以接受字节流。。。*/class anli{	public static void main (String[] args)throws Exception	{		while(true)		{			Socket s = new Socket ("192.168.109.119",10086);			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));			BufferedReader bfr = new BufferedReader(new InputStreamReader(s.getInputStream()));			//BufferedWriter bfw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));			PrintWriter pw = new PrintWriter(s.getOutputStream(),true);                  //使用printWriter的好处			String line = null;			while ((line = br.readLine())!=null)			{				if ("over".equals(line))				{					break;				}				//bfw.write(line);				//bfw.newLine();				//bfw.flush();				pw.println(line); //一个有了前面多个代码的功能				String str = bfr.readLine();				System.out.println("Server:::"+str);			}			br.close();//输入流要关闭。。。   这两个是不能关掉的，要不然就一直报错			s.close();		}	}}class rec{	public static void main (String[] args)throws Exception	{		ServerSocket ss = new ServerSocket(10086);		while(true)		{			Socket s = ss.accept();			BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));			//BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));			PrintWriter pw = new PrintWriter(s.getOutputStream(),true);  //一定要加上true，要不然的结果就是数据传递不出去。。。			String line = null;			while((line = br.readLine())!=null)			{				pw.println(line.toUpperCase());				//bw.write(line.toUpperCase());				//bw.newLine();				//bw.flush();			}			s.close();			ss.close();		}	}}