Java socket2

通过socket对象可以获取通信对方的socket信息

客户端：

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

public class TestServer {
    public static void main(String[] args) {
        try {
            ServerSocket s = new ServerSocket(8888);
            while(true) {
                Socket s1 = s.accept();
                OutputStream os = s1.getOutputStream();
                DataOutputStream dos = new DataOutputStream(os);
                dos.writeUTF("Hello"+s1.getInetAddress()+"#port"+s1.getPort()+"bye bye");
                dos.close();
                s1.close();
            }
        } catch(IOException e) {
            System.out.println("程序运行出错："+e);
        }
    }
}

用户端：

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

public class TestClient {
    public static void main(String[] args) {
        try {
            Socket s1 = new Socket("192.168.56.1",8888);
            InputStream is = s1.getInputStream();
            DataInputStream dis = new DataInputStream(is);
            System.out.println(dis.readUTF());
            dis.close();
            s1.close();
        } catch(ConnectException connExc) {
            connExc.printStackTrace();
            System.out.println("服务器连接失败！");
        } catch(IOException e) {
            e.printStackTrace();
        }
    }
}

结果：    Hello/192.168.56.1#port56660bye bye

s1.getInetAddress()    这个是拿到ip地址的意思，注意这里拿的是客户端的ip地址。因为这个s1拿的是对面client的ip

s1.getPort()        拿的是客户端的端口号  （注意，拿到的端口号可不是8888，8888是服务器的端口号，拿到的端口号56660是本身这个客户端连上去显示的端口号，是随机选的。）

然后我们试一个互相两边都能通话的例子：

server：

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

public class TestSocketServer {
    public static void main(String[] args) {
        InputStream in = null;
        OutputStream out = null;
        try {
            ServerSocket ss = new ServerSocket(5888);
            Socket socket = ss.accept();
            in = socket.getInputStream();
            out = socket.getOutputStream();
            DataOutputStream dos = new DataOutputStream(out);
            DataInputStream dis = new DataInputStream(in);
            String s = null ;
            if((s = dis.readUTF())!=null) {
                System.out.println(s);
                System.out.println("from"+socket.getInetAddress());
                System.out.println("port"+socket.getPort());
            }
        dos.writeUTF("hi,fuck you ");
        dis.close();
        dos.close();
        socket.close();
        } catch(IOException e) {
            e.printStackTrace();
        }
    }
}

client：

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

public class TestSocketClient {
    public static void main(String[] args) {
        InputStream is = null;
        OutputStream os = null;
        try {
            Socket socket = new Socket("localhost",5888);
            is = socket.getInputStream();
            os = socket.getOutputStream();
            DataInputStream dis = new DataInputStream(is);
            DataOutputStream dos = new DataOutputStream(os);
            dos.writeUTF("ok!yes you are right!");
            String s = null;
            if((s = dis.readUTF())!=null) {
                System.out.println(s);
            }
            dos.close();
            dis.close();
            socket.close();
        } catch(UnknownHostException e) {
            e.printStackTrace();
        } catch(IOException e) {
            e.printStackTrace();
        }
    }
}

必须是一个先读，一个先写。要是两个都先写，就会两个都卡在那。因为这个readUTF（）是堵塞式的。不然就会死死地卡在那。