网络编程之UDP协议和TCP协议

UDP协议和TCP协议

UDP协议(用户数据报协议): 需要一个发送端和接收端;
发送端:只负责发送数据,不管接收端是否接收到数据.
在传输数据的过程中是允许数据报丢失的;

特点:
    1.需要一个发送端和接收端;
    2.发送端只负责发送数据,不管接收端是否接收到数据;
    3.在传输数据的过程中是允许数据报丢失的;

TCP/IP协议:

    特点:
        1.需要一个客户端 和 服务器端;
        2.不允许出现数据报丢失;
        3.使用了三次握手的;

Tcp：

客户端：
1.获得Socket对象
Socket socket=new Socket(address, port);
//参数：address为要连接的电脑ip地址，port为端口
2.然后用socket对象获得i/o流
OutputStream outputStream = socket.getOutputStream();
3.用流写出文件（发送）
outputStream.write(“测试。。。”.getBytes());
4.假如有服务器回执信息
InputStream inputStream = socket.getInputStream();
5.然后读取回执信息
int read = inputStream.read();
6.最后关闭Socket流
socket.close();

public class TCPClient {
    public static void main(String[] args) throws Exception {
        // 获得客户端对象
        Socket socket = new Socket("192.168.145.107", 8888);
        // 读取本地文件
        BufferedInputStream bufferedInputStream = new BufferedInputStream(
                new FileInputStream(
                        "C:\\Users\\Administrator\\Pictures\\Camera Roll\\xm.jpg"));
        // 获得输出流
        OutputStream outputStream = socket.getOutputStream();
        int cha = -1;
        byte[] b = new byte[1024];
        while ((cha = bufferedInputStream.read(b)) != -1) {
            outputStream.write(b, 0, cha);
        }
        socket.shutdownOutput();
        //服务端返回信息处理
        InputStream inputStream = socket.getInputStream();
        byte[] c = new byte[1024];
        int len = inputStream.read(c);
        System.out.println(new String(c, 0, len));

        outputStream.close();
        socket.close();
        System.out.println("发送完毕！");
    }

}

服务端：
1.获得ServerSocket对象
ServerSocket serverSocket=new ServerSocket(port);
//此处port必须跟客户端端口保持一致， 不然接收不了数据
2.用ServerSocket对象的accpet()方法，获得Socket对象1
Socket socket = serverSocket.accept();
3.用获得的Socket对象创建读取流，读取客户端Socket发来的消息
InputStream inputStream = accept.getInputStream();
int read = inputStream.read();
4.关闭Socket跟ServerSocket
socket.close();
serverSocket.close();//这个可以不关

public class TCPServer {
    public static void main(String[] args) throws Exception {
        // 获得服务端对象
        ServerSocket serverSocket = new ServerSocket(8888);
        // 获得客户端的socket对象
        Socket socket = serverSocket.accept();
        // 获得socket流
        InputStream inputStream = socket.getInputStream();
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(
                new FileOutputStream("a.jpg"));
        byte[] b = new byte[1024];
        int len = -1;
        while ((len = inputStream.read(b)) != -1) {
            bufferedOutputStream.write(b, 0, len);
        }
        OutputStream outputStream = socket.getOutputStream();
        outputStream.write("接收到了，大兄弟！！！".getBytes());
        inputStream.close();
        socket.close();
    }

}

UDP：

发送端：
1.获得DatagramSocket对象
DatagramSocket datagramSocket=new DatagramSocket();
2.创建数据流，获取键盘输入
BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(System.in));
3.循环把输入的内容封装到DatagramPacket数据包对象中
String line=null;
while ((line=bufferedReader.readLine())!=null) {
byte[] b=line.getBytes();
DatagramPacket datagramPacket=new DatagramPacket(b, b.length, InetAddress.getByName(“192.168.145.107”),9001);
datagramSocket.send(datagramPacket);
}
4.关闭Socket流
datagramSocket.close();

public class UDPsent {
    public static void main(String[] args) throws Exception {
        System.out.println("开始发送！");
        // 创建DatagramSocket对象
        DatagramSocket datagramSocket = new DatagramSocket();
        // 创建读取流，获取键盘录入
        BufferedReader bufferedReader = new BufferedReader(
                new InputStreamReader(System.in));
        // 循环封装到DatagramPacket数据包中
        String line = null;
        while ((line = bufferedReader.readLine()) != null) {
            byte[] buf = line.getBytes();
            DatagramPacket datagramPacket = new DatagramPacket(buf, buf.length,
                    InetAddress.getByName("192.168.145.107"), 9000);
            datagramSocket.send(datagramPacket);
        }
        datagramSocket.close();

    }
}

获取端：
1.获得DatagramSocket对象注意要选带端口参数的构造方法
DatagramSocket datagramSocket=new DatagramSocket(9001);
2.创建数据包，并创建DatagramPacket对象，两个参数的。
byte[] bs=new byte[1024];
DatagramPacket datagramPacket=new DatagramPacket(bs, bs.length);
3.用Socket的receive方法获得数据包
datagramSocket.receive(datagramPacket);
4.用datagramPacket解析数据
byte[] data = datagramPacket.getData();
System.out.println(new String(data, 0, data.length));
5.关闭Socket流
datagramSocket.close();

public class UDPget {
    public static void main(String[] args) throws Exception {
        System.out.println("开始接收！");
        // 创建DatagramSocket对象并指定端口号，与发送方端口保持一致
        DatagramSocket datagramSocket = new DatagramSocket(9000);
        // 创建数据包，创建DatagramPacket对象
        byte[] b = new byte[1024];
        DatagramPacket datagramPacket = new DatagramPacket(b, b.length);
        // 利用Socket的receive方法接收数据
        datagramSocket.receive(datagramPacket);
        // 解析数据包
        byte[] data = datagramPacket.getData();
        int length = datagramPacket.getLength();
        System.out.println(new String(data, 0, length));
        // 关闭Socket流
        datagramSocket.close();
    }

}