文章目录
- 1.网络通信概述
- 2. 通信要素1:IP和端口号
- 2.1 IP和端口号
- 2.2 InetAddress 类
- 2.3 代码示例
- 3. 通信要素2:网络协议
- 3.1 网络协议概述
- 3.2 TCP网络编程
- 3.3 TCP网络编程三道例题
- 3.3.1 例一:
- 3.3.2 例二:
- 3.3.3 例三:
- 3.4 UDP网络通信
- 3.4.1 DatagramSocket&DatagramPacket 的常用方法
- 3.4.2 代码演示
- 3.5 URL编程
1.网络通信概述


2. 通信要素1:IP和端口号
2.1 IP和端口号


2.2 InetAddress 类


2.3 代码示例
public class InetAddressTest {
public static void main(String[] args) {
try {
InetAddress inet1 = InetAddress.getByName("192.168.10.14");
System.out.println(inet1);
InetAddress inet2 = InetAddress.getByName("www.baidu.com");
System.out.println(inet2);
InetAddress inet3 = InetAddress.getByName("127.0.0.1");
System.out.println(inet3);
InetAddress inet4 = InetAddress.getLoopbackAddress();
System.out.println(inet4);
System.out.println(inet2.getHostName());
System.out.println(inet2.getHostAddress());
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
}
3. 通信要素2:网络协议
3.1 网络协议概述







3.2 TCP网络编程




3.3 TCP网络编程三道例题

3.3.1 例一:
public class TCPTest1 {
@Test
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mm".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
@Test
public void server(){
ServerSocket ss = null;
Socket socket = null;
InputStream is = null;
ByteArrayOutputStream baos = null;
try {
ss = new ServerSocket(8899);
socket = ss.accept();
is = socket.getInputStream();
baos = new ByteArrayOutputStream();
byte[] buffer = new byte[5];
int len ;
while ((len = is.read(buffer)) != -1){
baos.write(buffer,0,len);
}
System.out.println(baos.toString());
System.out.println("收到了来自于:" + socket.getInetAddress().getHostAddress() + "的数据");
} catch (IOException e) {
e.printStackTrace();
} finally {
if (baos != null) {
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (ss != null) {
try {
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
3.3.2 例二:
public class TCPTest2 {
@Test
public void client() throws IOException {
Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9090);
OutputStream os = socket.getOutputStream();
FileInputStream fis = new FileInputStream("picture.png");
byte[] buffer = new byte[1024];
int len;
while ((len = fis.read(buffer)) != -1){
os.write(buffer,0,len);
}
fis.close();
os.close();
socket.close();
}
@Test
public void server() throws IOException {
ServerSocket ss = new ServerSocket(9090);
Socket socket = ss.accept();
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream("picture1.png");
byte[] buffer = new byte[1024];
int len ;
while ((len = is.read(buffer)) != -1){
fos.write(buffer,0 ,len);
}
fos.close();
is.close();
socket.close();
ss.close();
}
}
3.3.3 例三:
public class TCPTest3 {
@Test
public void client() throws IOException {
Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9090);
OutputStream os = socket.getOutputStream();
FileInputStream fis = new FileInputStream("picture.png");
byte[] buffer = new byte[1024];
int len;
while ((len = fis.read(buffer)) != -1){
os.write(buffer,0,len);
}
socket.shutdownOutput();
InputStream is = socket.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer1 = new byte[20];
int len1;
while ((len1 = is.read(buffer1)) != -1){
baos.write(buffer1,0,len1);
}
System.out.println(baos.toString());
fis.close();
os.close();
socket.close();
baos.close();
is.close();
}
@Test
public void server() throws IOException {
ServerSocket ss = new ServerSocket(9090);
Socket socket = ss.accept();
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream("picture2.png");
byte[] buffer = new byte[1024];
int len ;
while ((len = is.read(buffer)) != -1){
fos.write(buffer,0 ,len);
}
System.out.println("图片传输完成");
OutputStream os = socket.getOutputStream();
os.write("你好,照片已经收到".getBytes());
fos.close();
is.close();
socket.close();
ss.close();
os.close();
}
}
3.4 UDP网络通信

3.4.1 DatagramSocket&DatagramPacket 的常用方法





3.4.2 代码演示
public class UDPTest {
@Test
public void sender() throws IOException {
DatagramSocket socket = new DatagramSocket();
java.lang.String str = "我是UDP方式发送的导弹";
byte[] data = str.getBytes();
InetAddress inet = InetAddress.getLocalHost();
DatagramPacket packet = new DatagramPacket(data,0,data.length,inet,9090);
socket.send(packet);
socket.close();
}
@Test
public void receiver() throws IOException {
DatagramSocket socket = new DatagramSocket(9090);
byte[] buffer = new byte[100];
DatagramPacket packet = new DatagramPacket(buffer,0,buffer.length);
socket.receive(packet);
System.out.println(new String(packet.getData(),0,packet.getLength()));
socket.close();
}
}
3.5 URL编程






public class URLTest1 {
public static void main(String[] args) {
HttpURLConnection urlConnection = null;
InputStream is = null;
FileOutputStream fos = null;
try {
URL url = new URL("http://localhost:8080/examples/picture.png");
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
is = urlConnection.getInputStream();
fos = new FileOutputStream("day10\\picture3.png");
byte[] buffer = new byte[1024];
int len;
while ((len = is.read(buffer)) != -1){
fos.write(buffer,0,len);
}
System.out.println("下载完成");
} catch (IOException e) {
e.printStackTrace();
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (urlConnection != null)
urlConnection.disconnect();
}
}
}