Java使用TCP实现在线聊天的示例代码

package tcp.http;

import java.io.*;
import java.net.*;
import java.util.Scanner;

public class Client{
public static void main(String[] args) throws IOException{
Scanner scanner=new Scanner(System.in);
//1.创建Socket
Socket tcpClientSocket=new Socket();
//2.TCP要发送消息，必须先建立连接
byte[] IPv4={127,0,0,1};  //连接到本机
InetAddress serverAddress=InetAddress.getByAddress(IPv4);
SocketAddress serverSocketAddress=new InetSocketAddress(serverAddress,7777);
tcpClientSocket.connect(serverSocketAddress);//连接上了，（连接过程代码比较长，但是没有什么复杂的，只需要查文档根据函数的构造过程，一步步来写就好了）

while(true){ //写个死循环来聊天
String request=scanner.nextLine();
//通过字节流写入请求
OutputStream os=tcpClientSocket.getOutputStream();
//通过打印流打印和写入
PrintStream out=new PrintStream(os,true,"UTF-8");
out.println(request);
//通过字节流读取响应
InputStream is=tcpClientSocket.getInputStream();
BufferedReader reader=new BufferedReader(new InputStreamReader(is,"UTF-8")); //通过readLine()来保证每次都能把一句完整的话读完（\r\n是标志）;
String response=reader.readLine();
System.out.println("      "+response);
}
//tcpClientSocket.close();
}
}

package tcp.threads;

import java.io.*;
import java.net.*;
import java.util.Scanner;
import java.util.concurrent.*;

public class Server{

private static class TalkRunnable implements Runnable{ //一个个的工作线程
private Socket clientSocket;
TalkRunnable(Socket socket){
this.clientSocket=socket;
}
@Override
public void run(){
try{
InetAddress clientAddress=clientSocket.getInetAddress();
int clientPort=clientSocket.getPort();
System.out.printf("ID为 %s:%d 的好友上线了%n",clientAddress.getHostAddress(),clientPort);
//获取字节流
InputStream is=null;
is=clientSocket.getInputStream();
//字节流转换为字符流
InputStreamReader 
isReader=null;
isReader=new InputStreamReader(is,"UTF-8");
//获取输出字节流
OutputStream os=clientSocket.getOutputStream();
//获取打印流
PrintStream out=new PrintStream(os,true,"UTF-8");
//获取缓冲字符流
BufferedReader reader=new BufferedReader(isReader);
while(true){ //死循环聊天
String line=reader.readLine();
System.out.println("      好友说："+line);
Scanner scanner=new Scanner(System.in);
String response=scanner.nextLine();
out.println(response);
}
}catch(IOException e){
e.printStackTrace();
}
}
}

public static void main(String[] args) throws IOException{
//监听连接
ServerSocket tcpServerSocket=new ServerSocket(7777);
//定义阻塞队列
BlockingQueue<Runnable> queue=new LinkedBlockingQueue<>();
//创建线程池
ExecutorService pool=new ThreadPoolExecutor(100,100,0,TimeUnit.MILLISECONDS,queue);

while(true){
//TCP 要发送消息必须先建立连接
Socket clientSocket=tcpServerSocket.accept();
pool.execute(new TalkRunnable(clientSocket));//有一个客户端连接到服务器，就起一个线程来专门处理这个对话
}
}
}