InetAddress类

这个类代表的是一个ip地址

ip地址

 

 常用方法：

InetAddress byName = InetAddress.getByName("www.baidu.com");

InetAddress byName1 = InetAddress.getByName("127.0.0.1");

InetAddress byName2 = InetAddress.getByName("localhost");

InetAddress localHost = InetAddress.getLocalHost();

byName1.getHostName();

byName1.getHostAddress();
===============================================
端口号：用来标识计算机上运行的进程。

 

 

======================================================
网络协议：

 

 

实现通信的几个步骤：
客户端：
1，创建socket对象，指明服务器端的ip和端口号
2，获取一个输出流，用于输出数据
3，输出数据
4，资源关闭
服务器端：
1，创建服务器端的serversocket，指明自己的端口号
2，调用accept方法，表示接受来自客户端的socket
3，获取输入流
4，读取输入流中的数据
5，关闭资源

public class TCPTest {

       public void client () {
            Socket socket = null;
            OutputStream os = null;
            try {
                InetAddress inet = InetAddress.getByName("127.0.0.1");
                socket = new Socket(inet, 8899);
                os = socket.getOutputStream();
                os.write("你好，我是客户端".getBytes());
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (os != null)
                        os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    if (socket != null)
                        socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }


        }

        public void server () {
            ServerSocket serverSocket = null;
            Socket accept = null;
            InputStream is = null;
            ByteArrayOutputStream bs = null;
            try {
                serverSocket = new ServerSocket(8899);
                accept = serverSocket.accept();
                is = accept.getInputStream();

                bs = new ByteArrayOutputStream();
                byte[] buff = new byte[5];
                int len;
                while ((len = is.read(buff)) != -1) {
                    bs.write(buff, 0, len);
                }
                String s = bs.toString();
                System.out.println(s);
                System.out.println(accept.getInetAddress().getHostAddress());
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (bs != null)
                        bs.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    if (is != null)
                        is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    if (accept != null)
                        accept.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    if (serverSocket != null)
                        serverSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }

}

==============================================================
从客户端发送一个文件到服务端：

public void client() throws IOException {
    Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9090);
    OutputStream os = socket.getOutputStream();
    FileInputStream fis = new FileInputStream(new File("Inet.iml"));
    byte[] buf=new byte[1024];
    int len;
    while ((len=fis.read(buf))!=-1){
        os.write(buf,0,len);
    }
    fis.close();
    os.close();
    socket.close();

}
public void server() throws IOException {
    ServerSocket serverSocket = new ServerSocket(9090);
    Socket accept = serverSocket.accept();
    InputStream is= accept.getInputStream();
    FileOutputStream fos = new FileOutputStream("d\\1234.iml");

    byte[] buff = new byte[5];
    int len;
    while ((len = is.read(buff)) != -1) {
        fos.write(buff, 0, len);
    }
    fos.close();
    is.close();
    accept.close();
    serverSocket.close();

}
============================================================
客户端给服务端发文件，然后服务端给客户端发个反馈

public void client() throws IOException {
    Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9090);
    OutputStream os = socket.getOutputStream();
    FileInputStream fis = new FileInputStream(new File("Inet.iml"));
    byte[] buf=new byte[1024];
    int len;
    while ((len=fis.read(buf))!=-1){
        os.write(buf,0,len);
    }
    socket.shutdownOutput();//关闭数据输出

    InputStream is = socket.getInputStream();
    ByteArrayOutputStream bs = new ByteArrayOutputStream();
    byte[] buff = new byte[5];
    int len1;
    while ((len1 = is.read(buff)) != -1) {
        bs.write(buff, 0, len1);
    }
    String s = bs.toString();
    System.out.println(s);

    bs.close();
    is.close();
    fis.close();
    os.close();
    socket.close();

}
public void server() throws IOException {
    ServerSocket serverSocket = new ServerSocket(9090);
    Socket socket = serverSocket.accept();
    InputStream is= socket.getInputStream();
    FileOutputStream fos = new FileOutputStream("d\\1234.iml");

    byte[] buff = new byte[5];
    int len;
    while ((len = is.read(buff)) != -1) {
        fos.write(buff, 0, len);
    }

    OutputStream os = socket.getOutputStream();
    os.write("你好，数据收到".getBytes());

    os.close();
    fos.close();
    is.close();
    socket.close();
    serverSocket.close();

}
=========================================================

UTP发送端给接收端发信息：

public void sender() throws IOException {
    DatagramSocket socket = new DatagramSocket();
    String str="我是东1";
    byte[]by=str.getBytes();
    InetAddress inet = InetAddress.getLocalHost();
    DatagramPacket dp = new DatagramPacket(by,0,by.length,inet,9090);

    socket.send(dp);
    socket.close();
}
public void receiver() throws IOException {
    DatagramSocket socket = new DatagramSocket(9090);
    byte[]buf=new byte[20];
    DatagramPacket dp = new DatagramPacket(buf,0,buf.length);
    socket.receive(dp);

    System.out.println(new String(dp.getData(),0,dp.getLength()));//getData()可以返回一个字节数组
    socket.close();
}

====================================================
URL编程：

 

 

常用方法：

 

 从网上下载个资源：

public class URLTest {
    public static void main(String[] args) {
        HttpURLConnection urlConnection = null;
        InputStream is= null;
        FileOutputStream fos = null;
        try {
            URL url = new URL("http://=.........................");
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.connect();
            is = urlConnection.getInputStream();
            fos = new FileOutputStream("wode.jpg");
            byte[]buf=new byte[1024];
            int len;
            while ((len=is.read(buf))!=-1){
                fos.write(buf,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {

            try {
                if (fos!=null)
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (is!=null)
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {if (urlConnection!=null)
                urlConnection.disconnect();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }




    }
}