TCP通信快速入门

客户端 :
public class SocketDemo01 {
    public static void main(String[] args) {
        try {
            //1. 创建Socket通信管道请求有服务端的链接
            //public Socket(String host, int port)
            //参数一:服务端的IP地址
            //参数二:服务端的端口
            Socket socket = new Socket("127.0.0.1",9999);

            //2.从socket通信管道中得到一个字节输出流, 负责发送数据
            OutputStream os = socket.getOutputStream();

            //3.把低级的字节流包装成打印流
            PrintStream printStream = new PrintStream(os);
            printStream.println("消息发出来了");
            printStream.flush();//记得刷新

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
服务端:

public class ACC {
    public static void main(String[] args) throws Exception{
        //1.注册端口
        ServerSocket serverSocket = new ServerSocket(9999);
        //2.必须调用accept方法:  等待接受客户点的Socket连接请求, 建立Socket通信管道
        Socket socket = serverSocket.accept();
        //3.从socket通信管道中得到一个字节输入流
        InputStream is = socket.getInputStream();
        //4.把字节输入流包装成缓冲字符输入流进行消息的接收
        InputStreamReader inputStreamReader = new InputStreamReader(is);//转换流(将字节输入流转换成字符输入流)
        BufferedReader br = new BufferedReader(inputStreamReader);
        //按行读取消息
        String rs;
        if ((rs = br.readLine()) != null){ //用if进行判断一次
            System.out.println(socket.getRemoteSocketAddress()+"说了"+rs);
        }
    }
}