import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.InetAddress;import java.net.Socket;/* 需求： 客户端与服务端一问一答聊天。   1.如果使用BuffrerdReader的readline方法一定要加上\r\n才把数据写出。 2.使用字符流一定要调用flush方法数据才会写出。  *///聊天的客户端public class ChatClient {    public static void main(String[] args) throws IOException {        //建立tcp的客户端服务        Socket socket = new Socket(InetAddress.getLocalHost(),9090);        //获取socket的输出流对象。        OutputStreamWriter socketOut =    new OutputStreamWriter(socket.getOutputStream());        //获取socket的输入流对象        BufferedReader socketReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));                //获取键盘的输入流对象，读取数据        BufferedReader keyReader = new BufferedReader(new InputStreamReader(System.in));                String line = null;        //不断的读取键盘录入的数据，然后把数据写出        while((line = keyReader.readLine())!=null){            socketOut.write(line+"\r\n");            //刷新            socketOut.flush();                        //读取服务端回送的数据            line = socketReader.readLine();            System.out.println("服务端回送的数据是："+line);        }        //关闭资源        socket.close();    }        }

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.ServerSocket;import java.net.Socket;/* 聊天的服务端 */public class ChatServer {    public static void main(String[] args) throws IOException {        //建立tcp的服务端        ServerSocket serverSocket = new ServerSocket(9090);        //接受客户端的连接，产生一个SOcket        Socket socket = serverSocket.accept();        //获取到Socket的输入流对象        BufferedReader socketReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));                //获取到Socket输出流对象        OutputStreamWriter socketOut =  new OutputStreamWriter(socket.getOutputStream());                //获取键盘的输入流对象        BufferedReader keyReader = new BufferedReader(new InputStreamReader(System.in));                        //读取客户端的数据        String line = null;        while((line = socketReader.readLine())!=null){            System.out.println("服务端接收到的数据："+ line);                        System.out.println("请输入回送给客户端的数据：");            line = keyReader.readLine();            socketOut.write(line+"\r\n");            socketOut.flush();        }                //关闭资源        serverSocket.close();    }    }