Java网络编程学习（笨蛋笔记）
网络编程
文章目录
- 网络编程
- 1.1、TCP/IP参考模型
- 1.1 网络编程问题的了解
- 1.2 、网络通信的要素
- 1.3、测试IP 常用方法
- 1.4、端口
- 1.5 、通信协议
- 1.6、TCP
- 案例1：TCP实现聊天
- 案例2：TCP文件上传
- 1.7 Tomcat
- 1.8、UDP
- 1.发送信息
- 2.咨询
- 3. UDP多线程在线咨询
- 1.9、 URL
- 1.10 URL 下载 音乐
1.1、TCP/IP参考模型
1.1 网络编程问题的了解
- 网络编程中有两个主要的问题
- 如何准确的定位到网络上的一台或者多台主机
- 找到主机之后如何进行通信
- 网络编程中的要素
- IP 和 端口号
- 网络通信协议 UDP ， TCP
1.2 、网络通信的要素
IP地址： InetAddress（类）
- 唯一定位一台网络上计算机
- 127.0.0.1 : 本机 localhost
- ip地址的分类：
- IPV4 / IPV6
- IPV4 127.0.0.1 , 4个字节组成 ，0 ~ 255
- IPV6 : 128位。 8个无符号整数！
- 公网（互联网） - 私网（局域网）
- ABCD类地址
- IPV4 / IPV6
1.3、测试IP 常用方法
package com.lan.network;
import java.net.InetAddress;
import java.net.UnknownHostException;
//测试 IP
public class TestInetAddress {
public static void main(String[] args) throws UnknownHostException {
//查询本机地址
InetAddress inetAddress1 = InetAddress.getByName("127.0.0.1");
System.out.println(inetAddress1);
InetAddress inetAddress2 = InetAddress.getByName("localhost");
System.out.println(inetAddress2);
InetAddress inetAddress3 = InetAddress.getLocalHost();
System.out.println(inetAddress3);
//查询网站ip地址
InetAddress inetAddress4 = InetAddress.getByName("www.baidu.com");
System.out.println(inetAddress4);
//常用方法
//System.out.println(inetAddress2.getAddress());
System.out.println(inetAddress2.getCanonicalHostName()); //规范的名字
System.out.println(inetAddress2.getHostAddress()); //ip
System.out.println(inetAddress2.getHostName()); //域名，或自己电脑的名字
}
}
1.4、端口
端口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 0 ~ 65535
-
TCP， UDP
-
端口分类
- 公有端口 0 ~ 1023
- HTTP : 89
- HTTPS : 443
- FTP : 21
- Telent : 23
-
程序注册端口 : 1024 ~ 49151 ，分配用户或者程序
- Tomcat : 8080
- MySQL : 3306
- Oracle ：1521
-
动态、私有 ：49152 ~ 65535
netstat -ano #查看所有的端口 netstat -ano|findstr "5900" #查看指定的端口 tasklist|findstr "8992" #查看指定商品进程 Ctrl + shift + ESC #打开计算机的任务进程管理
package com.lan.network;
import java.net.InetSocketAddress;
public class TestInetSocketAddress {
public static void main(String[] args) {
InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080);
System.out.println(socketAddress);
InetSocketAddress socketAddress1 = new InetSocketAddress("localhost", 8080);
System.out.println(socketAddress);
System.out.println(socketAddress.getAddress());
System.out.println(socketAddress.getHostName()); //地址
System.out.println(socketAddress.getPort()); //端口
}
}
1.5 、通信协议
协议：双方的约定
网络通信协议：速率，传输码率，代码结构……
重要：
- TCP： 用户传输协议
- UDP: 用户数据报协议
TCP udp 对比
TCP : 打电话
-
连接，稳定
-
三次握手，四次挥手最少需要三次，保证稳定连接。 A : 你看什么？ B : 看你怎么了？ A : 打一架
四次挥手
- 客户端、服务端
- 传输完成，释放连接，效率低
UDP : 发短信
- 不连接，不稳定
- 客户端，服务端：没有明确的界限
- 不管有没有准备好，都可以发给你
1.6、TCP
案例1：TCP实现聊天
运行时：先启动服务端 ，后客户端
客户端
- 连接服务器 Socket
- 发送信息
package com.lan.network.lesson02;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
//客户端
public class TcpClientDemo01 {
public static void main(String[] args) {
Socket socket = null;
OutputStream os = null;
try {
//1.要知道服务器的地址，端口号
InetAddress serverIp = InetAddress.getByName("127.0.0.1");
int port = 9999;
//2.创建一个socket 连接
socket = new Socket(serverIp, port);
//3. 发关信息 IO流
os = socket.getOutputStream();
os.write("你好，大笨蛋".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();
}
}
}
}
}
服务端
- 建立服务的商品 ServerSocket
- 等待用户的链接 accept
- 接收用户的消息
package com.lan.network.lesson02;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
//服务端
public class TcpServerDeom01 {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket socket = null;
InputStream is = null;
ByteArrayOutputStream baos = null;
try {
//1.我得有一个地址
serverSocket = new ServerSocket(9999);
//循环可以一直接收
while (true){
//2.等待客户端连接过来
socket = serverSocket.accept();
//3.读取客户端的消息
is = socket.getInputStream();
//管道流
baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while((len = is.read(buffer))!=-1){
baos.write(buffer,0,len);
}
System.out.println(baos.toString());
}
} catch (IOException e) {
e.printStackTrace();
}finally{
//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(serverSocket!=null){
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
案例2：TCP文件上传
服务端
package com.lan.network.lesson02;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
//服务端
public class TcpServerDemo02 {
public static void main(String[] args) throws Exception {
//1.创建服务
ServerSocket serverSocket = new ServerSocket(9000);
//2.监听客户端的连接
Socket socket = serverSocket.accept();//阻塞式监听，会一直等待客户端连接
//3.获取输入流
InputStream is = socket.getInputStream();
//4.文件输出
FileOutputStream fos = new FileOutputStream(new File("receive1.jpg"));
byte[] buffer = new byte[1024];
int len;
while((len = is.read(buffer)) != -1){
fos.write(buffer,0,len);
}
//通知客户端我接收完毕了
OutputStream os = socket.getOutputStream();
os.write("我接受完毕了，你可以断开了".getBytes());
//关闭资源
fos.close();
is.close();
socket.close();
serverSocket.close();
}
}
客户端
package com.lan.network.lesson02;
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
//客户端
public class TcpClientDemo02 {
public static void main(String[] args) throws Exception {
//1.创建一个Socket 连接
Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
//2.创建一个输出流
OutputStream os = socket.getOutputStream();
//3.读取文件
FileInputStream fis = new FileInputStream(new File("1.jpg"));
//4.写出文件
byte[] buffer = new byte[1024];
int len;
while((len = fis.read(buffer)) != -1){
os.write(buffer,0,len);
}
//通知服务器，我已经结束了
socket.shutdownOutput(); //我已经传输完成了
//确定服务器接收完毕，才能够断开连接
InputStream inputStream = socket.getInputStream();
//String byte[]
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer2 = new byte[1024];
int len2;
while((len2=inputStream.read(buffer2)) != -1){
baos.write(buffer2 , 0 , len2);
}
System.out.println(baos.toString());
//关闭资源
baos.close();
inputStream.close();
fis.close();
os.close();
socket.close();
}
}
1.7 Tomcat
下载地址：https://tomcat.apache.org/download-90.cgi
安装教程：https://blog.csdn.net/m0_37292262/article/details/80622840
服务端
- 自定义 S
- Tomcat 服务器 S : Java后台开发！
客户端
- 自定义 C
- 浏览器 B
1.8、UDP
1.发短信： 不用连接，需要知道对方的地址！
1.发送信息
package com.lan.network.lesson03;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
//不需要连接服务器
public class UdpClientDeom01 {
public static void main(String[] args) throws Exception {
//1.建立一个Socket
DatagramSocket socket = new DatagramSocket();
//2.建个包
String msg = "你好啊,服务器！";
InetAddress localhost = InetAddress.getByName("localhost");
int port = 9090;
//数据，数据的长度起始，要发送给谁
DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.length(), localhost, port);
//3.发送包
socket.send(packet);
//4.关闭流
socket.close();
}
}
- 接收端
package com.lan.network.lesson03;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
//还是要等待客户端的链接！
public class UdpServerDeom01 {
public static void main(String[] args) throws Exception {
//开放端口
DatagramSocket socket = new DatagramSocket(9090);
//接收数据包
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
socket.receive(packet); //阻塞接收
System.out.println(packet.getAddress().getHostAddress());
System.out.println(new String(packet.getData(),0,packet.getLength()));
//关闭连接
socket.close();
}
}
2.咨询
2.1 循环发送消息
package com.lan.network.chat;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;
public class UdpsenderDeom01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(8888);
while (true) {
//准备数据 ： 控制台读取 System.in
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String data = reader.readLine();
byte[] datas = data.getBytes();
DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 6666));
socket.send(packet);
if(data.equals("bye")){
break;
}
}
socket.close();
}
}
2.2 循环接收消息
package com.lan.network.chat;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class UdpReceiveDemo01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666);
while (true){
//准备接收包裹
byte[] container = new byte[1024];
DatagramPacket packet = new DatagramPacket(container, 0, container.length);
socket.receive(packet); //阻塞式接收包裹
//断开连接 bye
byte[] data = packet.getData();
String receiveData = new String(data, 0, data.length);
System.out.println(receiveData);
if(receiveData.equals("bye")){
break;
}
}
socket.close();
}
}
3. UDP多线程在线咨询
在线咨询：两个都可以发送，也都可以接收对方！
接收
package com.lan.network.chat;
import java.io.IOException;
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 msgFrom;
public TalkReceive(int port, String msgFrom) {
this.port = port;
this.msgFrom = msgFrom;
try {
socket = new DatagramSocket(port);
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
while (true){
//准备接收包裹
try {
byte[] container = new byte[1024];
DatagramPacket packet = new DatagramPacket(container, 0, container.length);
socket.receive(packet); //阻塞式接收包裹
//断开连接 bye
byte[] data = packet.getData();
String receiveData = new String(data, 0, data.length);
System.out.println(msgFrom + ":"+receiveData);
if(receiveData.equals("bye")){
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
socket.close();
}
}
发送
package com.lan.network.chat;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
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 (Exception e) {
e.printStackTrace();
}
}
@Override
public void run() {
while (true) {
try {
String data = reader.readLine();
byte[] datas = data.getBytes();
DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress(this.toIP,this.toPort));
socket.send(packet);
if(data.equals("bye")){
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
socket.close();
}
}
两个多线程
package com.lan.network.chat;
public class TalkStudent {
public static void main(String[] args) {
//开启两个线程
new Thread(new TalkSend(7777,"localhost",9999)).start();
new Thread(new TalkReceive(8888,"老师")).start();
}
}
package com.lan.network.chat;
public class TalkTeacher {
public static void main(String[] args) {
new Thread(new TalkSend(5555,"localhost",8888)).start();
new Thread(new TalkReceive(9999,"学生")).start();
}
}
1.9、 URL
常用的方法
package com.lan.network.lesson04;
import java.net.MalformedURLException;
import java.net.URL;
public class URLDEmo01 {
public static void main(String[] args) throws MalformedURLException {
URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=xiaolan&password=123");
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
}
}
1.10 URL 下载 音乐
疑心病（下载）歌
package com.lan.network.lesson04;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
public class UrlDown {
public static void main(String[] args) throws IOException {
//1.下载地址
//疑心病 （下载）
URL url = new URL("https://m701.music.126.net/20200419190215/c94dc8e3d060688b806b997c4d0c83cb/jdyyaac/0708/545a/5253/0b53065607c0714a001de984d58a5b06.m4a");
//2.连接到这个资源 HTTP
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos = new FileOutputStream("晴天.m4a");
byte[] buffer = new byte[1024];
int len;
while((len = inputStream.read(buffer)) != -1){
fos.write(buffer,0,len);
}
fos.close();
inputStream.close();
urlConnection.disconnect(); //断开连接
}
}