服务器端代码：

package InternetCode.Socket.Exa507;
import java.io.*;
import java.net.*;
import java.util.Scanner;public class ServerSocketFrame{private PrintWriter writer; // 声明PrintWriter类对象private BufferedReader reader; // 声明BufferedReader对象private ServerSocket server; // 声明ServerSocket对象private Socket socket; // 声明Socket对象socketprivate Scanner scanner;public void getServer() {try {server = new ServerSocket(1978); // 实例化Socket对象System.out.println("服务器套接字已经创建成功\n"); // 输出信息while (true) { // 如果套接字是连接状态System.out.println("等待客户机的连接......\n"); // 输出信息socket = server.accept(); // 实例化Socket对象reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); // 实例化BufferedReader对象writer = new PrintWriter(socket.getOutputStream(), true);getClientInfo(); // 调用getClientInfo()方法}} catch (Exception e) {e.printStackTrace(); // 输出异常信息}}private void getClientInfo() {try {while (true) { // 如果套接字是连接状态String line = reader.readLine();if (line != null)System.out.println("接收到客户机发送的信息：" + line + "\n"); // 获得客户端信息}} catch (Exception e) {System.out.println("客户端已退出。\n"); // 输出异常信息} finally {try {if (reader != null) {reader.close();// 关闭流}if (socket != null) {socket.close(); // 关闭套接字}} catch (IOException e) {e.printStackTrace();}}}private void sendInfoToClient(){while(true){scanner=new Scanner(System.in);System.out.println("请输入要发送的消息:");String text=scanner.nextLine();if(text.equals("quit")){break;}writer.println(text);}}public static void main(String[] args) { // 主方法ServerSocketFrame frame = new ServerSocketFrame(); // 创建本类对象//此线程用于监听接收消息new Thread(new Runnable() {@Overridepublic void run() {frame.getServer();}}).start();//此线程用发送消息给客户端new Thread(new Runnable() {@Overridepublic void run() {frame.sendInfoToClient();}}).start();}}

客户端代码：

package InternetCode.Socket.Exa507;
import java.io.*;
import java.net.*;
import java.util.Scanner;public class ClientSocketFrame {private PrintWriter writer; // 声明PrintWriter类对象private BufferedReader reader; // 声明BufferedReader对象private Socket socket; // 声明Socket对象private Scanner scanner;/*** 连接到服务器方法*/private void connect() { // 连接套接字方法System.out.println("尝试连接......\n"); // 文本域中信息信息try { // 捕捉异常socket = new Socket("127.0.0.1", 1978); // 实例化Socket对象while (true) {writer = new PrintWriter(socket.getOutputStream(), true);reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); // 实例化BufferedReader对象System.out.println("完成连接。\n"); // 文本域中提示信息getClientInfo();}} catch (Exception e) {e.printStackTrace(); // 输出异常信息}}/*** 对服务器的发送消息进行监听*/private void getClientInfo() {try {while (true) { // 如果套接字是连接状态if (reader != null) {String line = reader.readLine();if (line != null)System.out.println("接收到服务器发送的信息：" + line + "\n"); // 获得客户端信息}}} catch (Exception e) {e.printStackTrace();} finally {try {if (reader != null) {reader.close();// 关闭流}if (socket != null) {socket.close(); // 关闭套接字}} catch (IOException e) {e.printStackTrace();}}}/*** 向服务器发送消息方法*/private void sendInfoToServer(){while(true){scanner=new Scanner(System.in);System.out.println("请输入要发送的消息:");String text=scanner.nextLine();if(text.equals("quit")){break;}writer.println(text);}}public static void main(String[] args) { // 主方法ClientSocketFrame clien = new ClientSocketFrame(); // 创建本例对象//此线程用于监听接收消息new Thread(new Runnable() {@Overridepublic void run() {clien.connect(); // 调用连接方法}}).start();//此线程用发送消息给服务器new Thread(new Runnable() {@Overridepublic void run() {clien.sendInfoToServer(); // 调用连接方法}}).start();}
}

其精髓在于创建两个线程一个用户监听对方发送来的消息，一个用于自身发送消息。