Java网络编程之入门篇

Java网络编程之入门篇

目录一、网络基础二、网络协议URL类

一、网络基础

二、网络协议

实现TCP的网络编程

例子1：客户端发送信息给服务端，服务端将数据显示在控制台上

public class TCPTest1 {

//客户端

@Test

public void client() {

Socket socket = null;

OutputStream os = null;

try {

//1.创建Socket对象，指明服务器端的ip和端口号

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

socket = new Socket(inet, 8899);

//2.获取一个输出流，用于输出数据

os = socket.getOutputStream();

//3.写出数据的操作

os.write("你好，我是客户端mm".getBytes());

} catch (IOException e) {

e.printStackTrace();

} finally {

//4.资源的关闭

if(os != null){

try {

os.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if(socket != null){

try {

socket.close();

} catch (IOException e) {

e.printStamHGQdckTrace();

}

}

}

}

//服务端

@Test

public void server(){

ServerSocket ss = null;

Socket socket = null;

InputStream is = null;

ByteArrayOutputStream baos = null;

try {

//1.创建服务器的ServerSocket,指明自己的端口号

ss = new ServerSocket(8899);

//2.调用accept()表示接收来自于客户端的socket

socket = ss.accept();

//3.获取输入流

is = socket.getInputStream();

//不建议这样写，可能会有乱码

// byte[] buffer = new byte[1024];

// int len;

// while((len = is.read(buffer)) != -1){

// String str = new String(buffer,0,len);

// System.out.println(str);

// }

//4.读取输入流中的数据

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());

} catch (IOException e) {

e.printStackTrace();

} finally {

//5.关闭资源

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();

}

}

}

}

}

实现TCP的网络编程

例题2：客户端发送文件给服务端，服务端将文件保存在本地。

public class TCPTest2 {

//这里异常处理的方式应该使用try-catch-finally

@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(new File("beauty.jpg"));

byte[] buffer = new byte[1024];

int len;

while((len = fis.read(buffer)) != -1){

os.write(buffer,0,len);

}

fis.close();

os.close();

socket.close();

}

//这里异常处理的方式应该使用try-catch-finally

@Test

public void server() throws IOException {

ServerSocket ss = new ServerSocket(9090);

Socket socket = ss.accept();

InputStream is = socket.getInputStream();

FileOutputStream fos = new FileOutputStream(new File("beauty1.jpg"));

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();

}

}

实现TCP的网络编程

例题3：从客户端发送文件给服务端，服务端保存到本地，并返回"发送成功"给客户端。并关闭相应的连接

public class TCPTest3 {

@Test

public void client() throws IOException {

Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9090);

OutputStream os = somHGQdcket.getOutputStream();

FileInputStream fis = new FileInputStream(new File("beauty.jpg"));

byte[] buffer = new byte[1024];

int len;

while((len = fis.read(buffer)) != -1){

os.write(buffer,0,len);

}

//服务区端给予客户端反馈

OutputStream os1 = socket.getOutputStream();

os.write("你好，美女，照片我以收到，非常漂亮！".getBytes());

fis.close();

os.close();

socket.close();

os1.close();

}

//这里异常处理的方式应该使用try-catch-finally

@Test

public void server() throws IOException {

ServerSocket ss = new ServerSocket(9090);

Socket socket = ss.accept();

InputStream is = socket.getInputStream();

FileOutputStream fos = new FileOutputStream(new File("beauty2.jpg"));

byte[] buffer = new byte[1024];

int len;

while((len = is.read(buffer)) != -1){

fos.write(buffer,0,len);

}

//接受来自于服务器端的数据，并显示到控制台上

InputStream is1 = socket.getInputStream();

ByteArrayOutputStream baos = new ByteArrayOutputStream();

byte[] bufferr = new byte[20];

int len1;

while((len1 = is1.read(buffer)) != -1){

baos.write(buffer,0,len1);

}

System.out.println(baos.toString());

fos.close();

is.close();

socket.close();

ss.close();

baos.close();

}

}

UDP协议的网络编程

public class UDPTest {

@Test

public void sender() throws IOException {

DatagramSocket socket = new DatagramSocket();

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()));

}

URL类

URL网络编程

1.URL:统一资源定位符，对应着互联网的某一资源地址

2.格式：

http://localhost:8080/examples/beauty.jpg?username=Tom

协议 主机名 端口号 资源地址 参数列表

public class URLTest {

public static void main(String[] args) {

try {

URL url = new URL("http://localhost:8080/examples/beauty.jpg?username=Tom");

// public String getProtocol() 获取该URL的协议名

System.out.println(url.getProtocol());// http

// public String getHost() 获取该URL的主机名

System.out.println(url.getHost());//localhost

// public String getPort() 获取该URL的端口号

System.out.println(url.getPort());// 8080

// public String getPath() 获取该URL的文件路径

System.out.println(url.getPath());//examples/beauty.jpg

// public String getFile() 获取该URL的文件名

System.out.println(url.getFile());//examples/beauty.jpg?username=Tom

// public String getQuery() 获取该URL的查询名

System.out.println(url.getQuery());//username=Tom

} catch (MalformedURLException e) {

e.printStackTrace();

}

}

}

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