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1.局域网、广域网
2.IP地址是什么#xff1f; IP地址是标识主机在网络上的地址 IP地址是如何组成的#xff1f; 点分十进制#xff0c;将32位分为四个部分#xff0c;每个部分一个字节#xff…
网络一级目录二、socket套接字三、UDP数据报套接字四、TCP流套接字一级目录
1.局域网、广域网
2.IP地址是什么 IP地址是标识主机在网络上的地址 IP地址是如何组成的 点分十进制将32位分为四个部分每个部分一个字节范围是0-255 3.端口号是什么? 端口号是区分一台主机上不同的应用程序。 4.客户端和服务器 客户端是发起请求方。服务器是响应请求。 1.一对一形式客户端发送一个请求服务器响应一个请求 2.一对多形式客户端发送一个请求服务器响应多个请求 3.多对一形式客户端发送多个请求服务器响应一个请求 4.多对多形式客户端发送多个请求服务器响应多个请求。 5.协议 主机和主机之间通信需要遵循一些协议。 两台主机之间通信需要通过一个 五元组 来描述通信 五元组是什么 源ip,源端口目的ip,目的端口协议类型。 6.协议分段 1.OSI模型物理层-数据链路层-网络层-运输层-会话层-表示层-应用层 2.TCP/IP五层模型物理层-数据链路层-网络层-运输层-应用层 应用层应用程序 运输层只关注起点和终点 网络层关注网络中任意两台机器的网络通信路径和具体的传输方式 数据链路层相邻主机之间的数据传输 物理层网络传输的基础设施 下层协议给上层协议提供功能支持上层协议依赖下层协议。 7.网络编程 网络编程是什么 在网络上不同进程通过编码方式进行数据通信叫做网络编程。 二、socket套接字
1.socket套接字是什么? socket套接字是操作系统提供的网络通信技术是基于TCP/IP协议的操作基本单元。基于socket应用程序开发就是网络编程。 2.socket套接字的分类 1.数据报套接字基于UDP协议 2.流套接字:基于TCP协议 UDP和TCP的区别 UDP:1.无连接2.不可靠传输3.面向数据报4.全双工。 TCP:1.有连接2.可靠传输3.面向字节流4.全双工。 什么是可靠传输? 发送方知道接受方是否正确收到信息。 不可靠传输:发送发不知道接受方是否正确收到信息。 三、UDP数据报套接字
1.Java数据报套接字通信模型基于UDP协议 DatagramSocket:描述一个soket对象在操作系统中一切皆文件管理硬件设备和软件资源都是通过文件的方式来管理网卡是硬件设备要想操作网卡需要写一个socket文件通过读写socket文件来操作网卡。 socket实际上是一个文件描述符表。 DatagramPacket:描述一个UDP数据报。 2.利用DatagramSocket和DatagramPacket来写一个回显服务器(UDP socket)
//客户端
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.util.Scanner;public class UdpEchoClient02 {DatagramSocket socketnull;String serverIp;int serverPort;public UdpEchoClient02(String serverIp,int serverPort) throws SocketException {this.serverIpserverIp;this.serverPortserverPort;socketnew DatagramSocket();}//客户端需要知道服务器的ip地址和端口号public void start() throws IOException {Scanner innew Scanner(System.in);while (true){System.out.println(client02:用户输入请求-);String requestin.next();if(request.equals(exist)){System.out.println(系统退出);return;}DatagramPacket requestPacketnew DatagramPacket(request.getBytes(),request.getBytes().length,InetAddress.getByName(serverIp),serverPort);socket.send(requestPacket);DatagramPacket responsePacketnew DatagramPacket(new byte[4096],4096);socket.receive(responsePacket);String responsenew String(responsePacket.getData(),0,responsePacket.getLength());String logString.format([%s,%s],request:%s,response:%s,responsePacket.getAddress(),responsePacket.getPort(),request,response);System.out.println(log);}}public static void main(String[] args) throws IOException {UdpEchoClient02 udpEchoClient02new UdpEchoClient02(127.0.0.1,7010);udpEchoClient02.start();}
}
//服务器端:
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;//服务器端
public class UdpEchoService02 {DatagramSocket socketnull;public UdpEchoService02(int port) throws SocketException {socketnew DatagramSocket(port);}public void start() throws IOException {System.out.println(service02:启动服务器);while(true){DatagramPacket requestPacketnew DatagramPacket(new byte[4096],4096);socket.receive(requestPacket);String requestnew String(requestPacket.getData(),0,requestPacket.getLength());String responsegetResponse(request);DatagramPacket responsePacketnew DatagramPacket(response.getBytes(),response.getBytes().length,requestPacket.getSocketAddress());socket.send(responsePacket);String logString.format([%s,%d]:request:%s;response:%s,requestPacket.getAddress(),requestPacket.getPort(),request,response);System.out.println(log);}}public String getResponse(String request){return request;}public static void main(String[] args) throws IOException {UdpEchoService02 udpEchoService02new UdpEchoService02(7010);udpEchoService02.start();}
} 结果: 3.翻译程序 英译汉客户端输入请求为英文单词返回的响应式中文解释。 //客户端
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.util.Scanner;//客户端
public class UdpClient {DatagramSocket socketnull;String serverIp;int serverPort;public UdpClient(String serverIp,int serverPort) throws SocketException {this.serverIpserverIp;this.serverPortserverPort;socketnew DatagramSocket();}public void start() throws IOException {Scanner innew Scanner(System.in);while(true){//1.用户输入请求String requestin.next();if(request.equals(exit)){System.out.println(系统退出);return;}//2.根据用户输入构造请求,并将请求发送给服务器DatagramPacket requestPacketnew DatagramPacket(request.getBytes(),request.getBytes().length,InetAddress.getByName(serverIp),serverPort);socket.send(requestPacket);//3.接收服务器的响应DatagramPacket responsePacketnew DatagramPacket(new byte[4096],4096);socket.receive(responsePacket);//4.解析服务器响应String responsenew String(responsePacket.getData(),0,responsePacket.getLength());//5.日志打印String logString.format([%s,%d],request:%s,response:%s,responsePacket.getAddress(),responsePacket.getPort(),request,response);System.out.println(log);}}public static void main(String[] args) throws IOException {UdpClient udpClientnew UdpClient(127.0.0.1,9090);udpClient.start();}
}
//服务器
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.util.HashMap;//服务器端
public class UdpServer {DatagramSocket socketnull;HashMapString,String hashMapnew HashMap();public UdpServer(int port) throws SocketException {socketnew DatagramSocket(port);//初始化hashMaphashMap.put(你好,hello);hashMap.put(明天,tomorrow);hashMap.put(客户端,client);hashMap.put(服务器,server);}public void start() throws IOException {System.out.println(启动服务器);while(true){//1.接收用户请求DatagramPacket requestPacketnew DatagramPacket(new byte[4096],4096);socket.receive(requestPacket);//2.解析用户请求String requestnew String(requestPacket.getData(),0,requestPacket.getLength());//3.根据用户请求构造响应String responseprocess(request);DatagramPacket responsePacketnew DatagramPacket(response.getBytes(),response.getBytes().length,requestPacket.getSocketAddress());socket.send(responsePacket);//4.打印日志String logString.format([%s,%d]:request:%s,response:%s,responsePacket.getAddress(),responsePacket.getPort(),request,response);System.out.println(log);}}public String process(String request){return hashMap.getOrDefault(request,该词在词典中不存在);}public static void main(String[] args) throws IOException {UdpServer udpServernew UdpServer(9090);udpServer.start();}
} 客户端 服务器 4.扩展翻译器 上面代码用的是HashMap在下面的代码中让代码连接数据库待查词中文去数据库中查表查出对应的英文。 a.数据库设计
//1.数据库设计
//db.sql
create database if not exists test_2_8 ;
use test_2_8;drop table if exists translate;
create table translate (id int primary key auto_increment,chinese varchar(50),english varchar(50)
);
insert into translate values(null,你好,hello);
insert into translate values(null,服务器,server);
insert into translate values(null,客户端,client);b.针对数据表创建数据表对象
//创建数据表对象
//------------------------
// | id | chinese | english |
// ------------------------
// | 1 | 你好 | hello |
// | 2 | 服务器 | server |
// | 3 | 客户端 | client |
// ------------------------
public class Translate {private int id;private String chinses;private String english;Overridepublic String toString() {return Translate{ id id , chinses chinses \ , english english \ };}public int getId() {return id;}public void setId(int id) {this.id id;}public String getChinses() {return chinses;}public void setChinses(String chinses) {this.chinses chinses;}public String getEnglish() {return english;}public void setEnglish(String english) {this.english english;}
}
c.连接数据库
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;public class Util {private static final String URLjdbc:mysql://127.0.0.1:3306/test_2_8?characterEncodingutf8useSSLfalse;private static final String USERNAMEroot;private static final String PASSWORDroot;static DataSource dataSourcenew MysqlDataSource();public static Connection getConnection() throws SQLException {((MysqlDataSource)dataSource).setUrl(URL);((MysqlDataSource)dataSource).setUser(USERNAME);((MysqlDataSource)dataSource).setPassword(PASSWORD);return dataSource.getConnection();}public static void getClose(Connection connection, PreparedStatement statement, ResultSet resultSet){if(resultSet!null){try {resultSet.close();} catch (SQLException throwables) {throwables.printStackTrace();}}if(statement!null){try {statement.close();} catch (SQLException throwables) {throwables.printStackTrace();}}if(connection!null){try {connection.close();} catch (SQLException throwables) {throwables.printStackTrace();}}}
}
d.客户端代码
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.util.Scanner;public class UdpClient {String serverIp;int serverPort;DatagramSocket socketnull;public UdpClient(String serverIp,int serverPort) throws SocketException {this.serverIpserverIp;this.serverPortserverPort;socketnew DatagramSocket();}public void start() throws IOException {Scanner scannernew Scanner(System.in);while(true){System.out.println(-);//1.用户输入请求并且构造请求String requestscanner.next();if(request.equals(exit)){System.out.println(程序退出);return;}DatagramPacket requestPacketnew DatagramPacket(request.getBytes(),request.getBytes().length,InetAddress.getByName(serverIp),serverPort);//2.将请求发送服务器socket.send(requestPacket);//3.从服务器接收响应DatagramPacket responsePacketnew DatagramPacket(new byte[4096],4096);socket.receive(responsePacket);String responsenew String(responsePacket.getData(),0,responsePacket.getLength());//4.打印日志String logString.format([%s,%d]:request:%s,response:%s,responsePacket.getAddress(),responsePacket.getPort(),request,response);System.out.println(log);}}public static void main(String[] args) throws IOException {UdpClient udpClientnew UdpClient(127.0.0.1,9090);udpClient.start();}
}
e.服务器代码
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;//服务器
public class UdpServer {DatagramSocket socketnull;public UdpServer(int port) throws SocketException {socketnew DatagramSocket(port);}public void start() throws IOException {System.out.println(启动服务器);while(true){//1.接收请求DatagramPacket requestPacketnew DatagramPacket(new byte[4096],4096);socket.receive(requestPacket);//2.解析请求String requestnew String(requestPacket.getData(),0,requestPacket.getLength());//3.构造响应String responseprocess(request);DatagramPacket responsePacketnew DatagramPacket(response.getBytes(),response.getBytes().length,requestPacket.getSocketAddress());//4.给客户端发送响应socket.send(responsePacket);//打印日志String logString.format([%s,%d]:request:%s,response:%s,responsePacket.getAddress(),responsePacket.getPort(),request,response);System.out.println(log);}}public String process(String request){Connection connectionnull;PreparedStatement preparedStatementnull;ResultSet resultSetnull;Translate translatenew Translate();try{connectionUtil.getConnection();String sqlselect * from translate where chinese?;preparedStatementconnection.prepareStatement(sql);preparedStatement.setString(1,request);resultSetpreparedStatement.executeQuery();if(resultSet.next()){translate.setEnglish(resultSet.getString(english));}else{String tnew String(词典中不存在该词);return t;}}catch(SQLException e){e.printStackTrace();}finally {Util.getClose(connection,preparedStatement,resultSet);}return translate.getEnglish();}public static void main(String[] args) throws IOException {UdpServer servernew UdpServer(9090);server.start();}
} 结果展示 数据库 客户端 服务器 四、TCP流套接字 1.ServerSocket 2.Socket 2.写一个回显服务器 a.客户端
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;//客户端
public class TcpEchoClient02 {Socket socketnull;String serverIp;int serverPort;public TcpEchoClient02(String serverIp,int serverPort) throws IOException {this.serverIpserverIp;this.serverPortserverPort;socketnew Socket(serverIp,serverPort);}public void start(){Scanner innew Scanner(System.in);System.out.println(客户端);try(InputStream inputStreamsocket.getInputStream();OutputStream outputStreamsocket.getOutputStream()){while(true){System.out.println(-);String requestin.next();//将用户需求发送给服务器PrintWriter printWriternew PrintWriter(outputStream);printWriter.println(request);printWriter.flush();//接收服务器发送的响应Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){break;}String responsescanner.next();//打印日志String logString.format([%s,%d]:request:%s,response:%s,socket.getInetAddress(),socket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}finally {try {socket.close();} catch (IOException e) {e.printStackTrace();}}}public static void main(String[] args) throws IOException {TcpEchoClient02 tcpEchoClient02new TcpEchoClient02(127.0.0.1,9090);tcpEchoClient02.start();}
}
b.服务器
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;//服务器
public class TcpEchoServer02 {ServerSocket listenSocketnull;public TcpEchoServer02(int port) throws IOException {listenSocketnew ServerSocket(port);}public void start() throws IOException {System.out.println(启动服务器);while (true){Socket socketlistenSocket.accept();processConnection(socket);}}public void processConnection(Socket socket){String log2String.format([%s,%d],socket.getInetAddress(),socket.getPort());System.out.println(log2服务器连接成功);try(InputStream inputStreamsocket.getInputStream();OutputStream outputStreamsocket.getOutputStream()){while(true){Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){String logString.format([%s,%d],socket.getInetAddress(),socket.getPort());System.out.println(log客户端下线);break;}String requestscanner.next();String responseprocess(request);PrintWriter printWriternew PrintWriter(outputStream);printWriter.println(response);printWriter.flush();//打印日志String logString.format([%s,%d]:request:%s,response:%s,socket.getInetAddress(),socket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}finally {try {socket.close();} catch (IOException e) {e.printStackTrace();}}}public String process(String request){return request;}public static void main(String[] args) throws IOException {TcpEchoServer02 tcpEchoServer02new TcpEchoServer02(9090);tcpEchoServer02.start();}
} 结果展示: 客户端 服务器 上面的代码存在一个问题 在同一时间只能支持一个客户端去访问一个服务器。 如果想要代码实现在同一时间内多个客户端访问一个服务器该如何实现呢? 引入 多进程 只需要修改服务器代码模块 多线程下的服务器代码 idea编译器端默认一个类只能启动一次多个客户端需要多次启动客户端代码所以需要更改编译器的设置: 多线程—服务器端的代码
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;//多线程回显服务器
public class TcpThreadEchoServer {ServerSocket listenSocketnull;public TcpThreadEchoServer(int port) throws IOException {listenSocketnew ServerSocket(port);}public void start() throws IOException {System.out.println(启动服务器);while(true){Socket clientSocketlistenSocket.accept();Thread tnew Thread(){Overridepublic void run(){processConnection(clientSocket);}};t.start();}}public void processConnection(Socket clientSocket){String logString.format([%s,%d],clientSocket.getInetAddress(),clientSocket.getPort());System.out.println(log客户端上线);try(InputStream inputStreamclientSocket.getInputStream();OutputStream outputStreamclientSocket.getOutputStream()){while(true){Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){logString.format([%s,%d],clientSocket.getInetAddress(),clientSocket.getPort());System.out.println(log下线);break;}String requestscanner.next();String responseprocess(request);PrintWriter printWriternew PrintWriter(outputStream);printWriter.println(response);printWriter.flush();logString.format([%s,%d]:request:%s,response:%s,clientSocket.getInetAddress(),clientSocket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}}public String process(String request){return request;}public static void main(String[] args) throws IOException {TcpThreadEchoServer tcpThreadEchoServernew TcpThreadEchoServer(9090);tcpThreadEchoServer.start();}
} 上面代码涉及到线程的创建和销毁频繁的创建和销毁线程开销会比较大所以引入了线程池. 服务器端的代码需要进行改变 线程池—服务器端的代码
//线程池---回显服务器
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;//线程池--回显服务器
public class TcpThreadPoolServer {ServerSocket listenSocketnull;public TcpThreadPoolServer(int port) throws IOException {listenSocketnew ServerSocket(port);}public void start() throws IOException {System.out.println(启动服务器);while (true) {Socket socketlistenSocket.accept();//--------------------线程池---------------------------ExecutorService executorService Executors.newCachedThreadPool();executorService.submit(new Runnable(){Overridepublic void run(){processConnection(socket);}});}}public void processConnection(Socket socket){String logString.format(【%s,%d】:客户端上线了,socket.getInetAddress(),socket.getPort());System.out.println(log);try(InputStream inputStreamsocket.getInputStream();OutputStream outputstreamsocket.getOutputStream()){while(true){Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){logString.format([%s,%d],socket.getInetAddress(),socket.getPort());System.out.println(log客户下线);break;}String requestscanner.next();String responseprocess(request);PrintWriter printWriternew PrintWriter(outputstream);printWriter.println(response);printWriter.flush();logString.format([%s,%d]:request:%s,response:%s,socket.getInetAddress(),socket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}finally {try {socket.close();} catch (IOException e) {e.printStackTrace();}}}public String process(String request){return request;}public static void main(String[] args) throws IOException {TcpThreadPoolServer tcpThreadPoolServernew TcpThreadPoolServer(9090);tcpThreadPoolServer.start();}
} 结果客户端1 客户端2 服务器 场景:在某些时刻服务器会收到很多个请求服务器收到多个请求需要创建多个线程当请求过多的时候服务器资源(eg:CPU,内存资源)不够用服务器最后会崩溃。该如何解决在某些时刻服务器收到多个请求这种场景呢? 1.引入协程。协程比线程更轻量 2.IO多路复用 3.引入多个服务器。 3.利用tcp流套接字写一个翻译器–“汉译英”—连接数据库 数据库和数据表的创建和上面基于UDP的套接字实现方法是一样的。 只是客户端和服务器端的socket不一样。 a.客户端代码
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;//翻译器--客户端
public class TcpClient {Socket socketnull;String serverIp;int port;public TcpClient(String serverIp,int port) throws IOException {this.serverIpserverIp;this.portport;socketnew Socket(serverIp,port);}public void start(){Scanner innew Scanner(System.in);try(InputStream inputStreamsocket.getInputStream();OutputStream outputStreamsocket.getOutputStream()){while(true){System.out.println(-);String requestin.next();if(request.equals(exit)){break;}PrintWriter printWriternew PrintWriter(outputStream);printWriter.println(request);printWriter.flush();Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){break;}String responsescanner.next();String logString.format(【%s,%d】:request:%s,response:%s,socket.getInetAddress(),socket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}}public static void main(String[] args) throws IOException {TcpClient tcpClientnew TcpClient(127.0.0.1,9090);tcpClient.start();}
}
b.服务器端代码
import test0209.util.DBUtil;
import test0209.util.Translate;import javax.xml.transform.Result;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;//翻译器--服务器
public class TcpServer {ServerSocket listenSocketnull;public TcpServer(int port) throws IOException {listenSocketnew ServerSocket(port);}public void start() throws IOException {System.out.println(启动服务器);while(true){Socket socketlistenSocket.accept();ExecutorService executorService Executors.newCachedThreadPool();executorService.submit(new Runnable() {Overridepublic void run() {processConnection(socket);}});}}public void processConnection(Socket socket){String logString.format([%s,%d],socket.getInetAddress(),socket.getPort());System.out.println(log客户端上线);try(InputStream inputStreamsocket.getInputStream();OutputStream outputStreamsocket.getOutputStream()){while(true){Scanner scannernew Scanner(inputStream);if(!scanner.hasNext()){logString.format([%s,%d],socket.getInetAddress(),socket.getPort());System.out.println(log客户端下线);break;}String requestscanner.next();String responseprocess(request);PrintWriter printWriternew PrintWriter(outputStream);printWriter.println(response);printWriter.flush();logString.format([%s,%d]:request:%s,response:%s,socket.getInetAddress(),socket.getPort(),request,response);System.out.println(log);}} catch (IOException e) {e.printStackTrace();}}//翻译器public String process(String request){Connection connectionnull;PreparedStatement preparedStatementnull;ResultSet resultSetnull;try {connectionDBUtil.getConnection();String sqlselect * from translate where chinese?;preparedStatementconnection.prepareStatement(sql);preparedStatement.setString(1,request);resultSetpreparedStatement.executeQuery();if(!resultSet.next()){String lognew String(词典中不存在该词语);return log;}Translate translatenew Translate();translate.setEnglish(resultSet.getString(english));return translate.getEnglish();} catch (SQLException throwables) {throwables.printStackTrace();}return new String(没有查到);}public static void main(String[] args) throws IOException {TcpServer tcpServernew TcpServer(9090);tcpServer.start();}
} 结果截图 客户端1: 客户端2 服务器:
