TCP/IP网络编程

package lianxi1;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

import org.junit.Test;

public class TestTCP1 {
    // 客户端
    @Test
    public void client() {
        Socket s = null;
        InputStream is = null;
        OutputStream os = null;
        try {
            s = new Socket(InetAddress.getByName("127.0.0.1"), 9090);
            //s = new Socket(InetAddress.getByName("221.192.74.152"), 9090); //对方主机的IP地址
            os = s.getOutputStream();
            String str1 = "我是客户端,请接收";
            os.write(str1.getBytes());
            s.shutdownOutput();
            is = s.getInputStream();
            byte[] b = new byte[20];
            int len;
            while((len=is.read(b))!=-1){
                String str = new String(b,0,len);
                System.out.print(str);
            }
        } catch (Exception e) {
            // TODO: handle exception
        }
        finally{
        if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        if (os != null) {
            try {
                os.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        if (s != null) {
            try {
                s.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        }
    }

    // 服务器
    @Test
    public void server() {
        ServerSocket ss = null;
        Socket s = null;
        InputStream is = null;
        OutputStream os = null;
        try {
            ss = new ServerSocket(9090);
            s = ss.accept();
            is = s.getInputStream();
            byte[] b = new byte[20];
            int len;
            while ((len = is.read(b)) != -1) {
                String str = new String(b, 0, len);
                System.out.print(str);
            }
            
            os = s.getOutputStream();
            os.write("已收到客户端信息".getBytes());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
        finally{
        if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        if (is != null) {
            try {
                is.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if (s != null) {
            try {
                s.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        if (ss != null) {
            try {
                ss.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    }
}