网络编程详解
一、Ip地址
1.使用方法
目的：获得本地ip,以及常用方法的使用package com.Tang.net;
import java.net.InetAddress;
import java.net.UnknownHostException;
public class InetAddressTest {
public static void main(String[] args) {
try {
//查询本机地址
InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
System.out.println(inetAddress);
InetAddress inetAddress1 = InetAddress.getByName("localhost");
System.out.println(inetAddress1);
InetAddress inetAddress2 = InetAddress.getLocalHost();
System.out.println(inetAddress2);
System.out.println("==================");
//常用方法
System.out.println(inetAddress1.getHostName());//域名或者自己电脑的名字
System.out.println(inetAddress1.getHostAddress());//ip
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
}
运行结果图
二、端口
1.作用
端口号表示计算机上的一个程序的进程： 不同的进程有不同的端口号！用来区分软件！ 被规定为0-655352.端口分类
共有端口0 - 1023 Http : 80 Https: 443 Ftp : 21 Telent : 23 程序注册端口：2014-29151 Tomcat ： 8080 MySQL ：3306 Oracle ：1521 动态、私有：49152-65535package com.Tang.net;
import java.net.InetSocketAddress;
public class InetSocketAddressTest {
public static void main(String[] args) {
InetSocketAddress inetSocketAddress = new InetSocketAddress("127.0.0.1",8080);
InetSocketAddress inetSocketAddress1 = new InetSocketAddress("localhost",8080);
System.out.println(inetSocketAddress);
System.out.println(inetSocketAddress1);
System.out.println("===============");
//常用方法
System.out.println(inetSocketAddress.getAddress());
System.out.println(inetSocketAddress.getHostName());
System.out.println(inetSocketAddress.getPort());
}
}
运行结果图
三、Tcp
需要建立连接：也就是客户端必须与服务器端建立连接，在没有服务器端的情况下，运行客户端的代码就会报ConnectException1.实现消息发送
客户端代码package com.Tang.net.tcp;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.UnknownHostException;
public class TcpClintTest {
public static void main(String[] args){
Socket socket = null;
OutputStream os = null;
try {
//1.要知道服务器端的地址和端口号
InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
int port = 999;
//2.创建一个socket连接
socket = new Socket(inetAddress, port);
//3.创建一个输出流
os = socket.getOutputStream();
os.write("欢迎进入Twq的博客，创作不易，多多点赞收藏".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {//流的关闭
if(os != null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(socket != null){
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
服务器端代码
package com.Tang.net.tcp;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketTimeoutException;
public class TcpServerTest {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket accept = null;
InputStream is = null;
ByteArrayOutputStream bos = null;
try {
//1.提供服务器端的端口号
serverSocket = new ServerSocket(999);
while(true){
//2.等待客户端连接
accept = serverSocket.accept();
//3.读取客户端信息
is = accept.getInputStream();
//管道流去读取防止出现乱码的情况
bos = new ByteArrayOutputStream();
byte[] bytes = new byte[1024];
int len;
while((len = is.read(bytes))!= -1){
bos.write(bytes,0,len);
}
System.out.println(bos.toString());
}
} catch (IOException e) {
e.printStackTrace();
} finally { //流的关闭
if(bos != null){
try {
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(is != null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(accept != null){
try {
accept.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(serverSocket != null){
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
运行结果图
2.实现文件发送与接收
服务器端代码package com.Tang.net.tcp;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class FileTcpServerTest {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket socket = null;
InputStream is = null;
FileOutputStream fos = null;
OutputStream os = null;
try {
//1.提供端口号
serverSocket = new ServerSocket(9000);
//监听客户端的连接
socket = serverSocket.accept();
//获取客户端的输入流
is = socket.getInputStream();
//文件输出
fos = new FileOutputStream(new File("tx1.jpg"));
byte[] bytes = new byte[1024];
int len;
while((len = is.read(bytes))!= -1){
fos.write(bytes,0,len);
}
//告知客户端，服务器端已接收完毕
os = socket.getOutputStream();
os.write("我已接收完毕，你可已断开了".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {//关闭流
if(os != null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(fos != null){
try {
fos.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(serverSocket != null){
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
客户端代码
package com.Tang.net.tcp;
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
public class FileTcpClintTest {
public static void main(String[] args) {
Socket socket = null;
OutputStream os = null;
InputStream inputStream = null;
ByteArrayOutputStream baos = null;
FileInputStream fis = null;
try {
//1.获取服务器端的地址和端口号
socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
//2.创建输出流
os = socket.getOutputStream();
//3.读取图片文件
fis = new FileInputStream(new File("tx.jpg"));
//向服务器端写出图片
byte[] bytes = new byte[1024];
int len;
while((len = fis.read(bytes))!= -1){
os.write(bytes,0,len);
}
//通知服务器端，客户端已经发送完毕
socket.shutdownOutput();
//客户端接收服务器端发送的已接收完毕的信息
inputStream = socket.getInputStream();
//输出的管道流
baos = new ByteArrayOutputStream();
byte[] bytes1 = new byte[2014];
int len1;
while((len1 = inputStream.read(bytes1))!= -1){
baos.write(bytes1,0,len1);
}
System.out.println(baos.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {//关闭流
if(baos != null){
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(inputStream != null){
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(fis != null){
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(os != null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(socket != null){
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
运行结果图
四、UDP
不需要建立连接:也就是发送端只需要知道要接收端主机的ip和端口号就可以进行消息的发送，不需要与接收端进行连接1.实现发送与接收方的单个数据的发送与接收
发送方代码：package com.Tang.net.udp;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
//不需要连接服务器
public class UdpClintTest {
public static void main(String[] args) throws Exception {
//1.建立一个socket
DatagramSocket socket = new DatagramSocket();
//要发送的对象
InetAddress localhost = InetAddress.getByName("localhost");
int port = 9090;
//2.建立一个包
String msg = "你好服务器";
DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port);
//发送包裹
socket.send(packet);
socket.close();
}
}
发送方里DatagramPacket里的参数解释看其源码可知
接收方代码
package com.Tang.net.udp;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class UdpReceiveTest {
public static void main(String[] args) throws Exception {
//开放端口
DatagramSocket socket = new DatagramSocket(9090);
//接收数据
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
socket.receive(packet);
System.out.println(new String(packet.getData(),0,packet.getLength()));
//关闭流
socket.close();
}
}
2.实现发送方与接收方消息的持续发送与接收
发送方代码package com.Tang.net.udp;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
public class UdpSendTest {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(8888);
while(true){
//准备数据，从控制台输入数据
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String data = reader.readLine();//读取控制台输入的数据
DatagramPacket packet = new DatagramPacket(data.getBytes(),0,data.getBytes().length,new InetSocketAddress("localhost",6666));
socket.send(packet);
if(data.equals("bye")){
break;
}
}
socket.close();
}
}
接收方代码
package com.Tang.net.udp;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class UdpReceiveTest01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666);
while(true){
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes,0,bytes.length);
socket.receive(packet);
String reveiveData = new String(packet.getData(), 0, packet.getLength());
System.out.println(reveiveData);
if(reveiveData.equals("bye")){
break;
}
}
socket.close();
}
}
运行结果图
3.实现发送方与接收方相互发送与接收消息
老师和学生可能既是发送端又是接收端，实现两者相互聊天 发送消息代码package com.Tang.net.udp;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.*;
import java.nio.charset.StandardCharsets;
import static java.lang.System.*;
public class TalkSend implements Runnable{
DatagramSocket socket = null;
BufferedReader reader = null;
private int fromPort;
private String toIp;
private int toPort;
public TalkSend(int fromPort, String toIp, int toPort) {
this.fromPort = fromPort;
this.toIp = toIp;
this.toPort = toPort;
try {
socket = new DatagramSocket(fromPort);
reader = new BufferedReader(new InputStreamReader(System.in));
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
while(true){
try {
String data = reader.readLine();
byte[] bytes = data.getBytes();//不知道为啥哈，这里不单独写，在聊天的过程中会出现中文乱码
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length, new InetSocketAddress(this.toIp, this.toPort));
socket.send(packet);
if(data.equals("bye")){
break;
}
} catch (Exception e) {
e.printStackTrace();
}
}
socket.close();
}
}
接收消息
package com.Tang.net.udp;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class TalkReceive implements Runnable{
DatagramSocket socket = null;
private int port;
private String msgName;
public TalkReceive(int port, String msgName) {
this.port = port;
this.msgName = msgName;
try {
socket = new DatagramSocket(port);
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
try {
while (true){
byte[] bytes = new byte[1024];
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
socket.receive(packet);
String receiveData = new String(packet.getData(), 0, packet.getLength());
System.out.println(msgName + ":" + receiveData);
if(receiveData.equals("bye")){
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
socket.close();
}
}
学生端
package com.Tang.net.udp;
public class TalkStudent {
public static void main(String[] args) {
new Thread(new TalkSend(666,"localhost",777)).start();//作为发送端时，接收端的端口号为777，自己发出的消息端口号为666
new Thread(new TalkReceive(888,"老师")).start();//作为接收端时，接收消息的端口号为888
}
}
老师端
package com.Tang.net.udp;
public class TalkTeacher {
public static void main(String[] args) {
new Thread(new TalkSend(999,"localhost",888)).start();//作为发送端时，自己发送消息的接口为999，接收方的端口为888
new Thread(new TalkReceive(777,"学生")).start();//作为接收端时，接收消息的端口号为777
}
}
运行结果图
五、URL下载
package com.Tang.net.url;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
public class URLtest {
public static void main(String[] args) throws IOException {
URL url = new URL("http://music.163.com/song/media/outer/url?id=1359331363.mp3");
// System.out.println(url.getProtocol());//协议
// System.out.println(url.getHost());//主机IP
// System.out.println(url.getPort());//端口
// System.out.println(url.getPath());//文件
// System.out.println(url.getFile());//全路径
// System.out.println(url.getQuery());//参数
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos= new FileOutputStream("j.mp3");
byte[] bytes = new byte[1024];
int len;
while((len = inputStream.read(bytes))!= -1){
fos.write(bytes,0,len);
}
fos.close();
inputStream.close();
urlConnection.disconnect();//断开连接
}
}
