/*
 * TCPMailClient.java
 * Copyright (c) 2020-12-09
 * author : Charzous
 * All right reserved.
 */
 
import java.io.*;
import java.net.Socket;
 
public class TCPMailClient {
    private Socket socket;
 
    private PrintWriter pw;
    private BufferedReader br;
 
    /**
     * @param ip
     * @param port
     * @return
     * @author Charzous
     * @date 2020/12/9 11:19
     *
     */
    public TCPMailClient(String ip, String port) throws IOException{
        //主动向服务器发起连接，实现TCP三次握手
        //不成功则抛出错误，由调用者处理错误
        socket =new Socket(ip,Integer.parseInt(port));
 
        //得到网络流输出字节流地址，并封装成网络输出字符流
        OutputStream socketOut=socket.getOutputStream();
        //参数true表示自动flush数据
        pw=new PrintWriter(new OutputStreamWriter(socketOut,"utf-8"),true);
 
        //得到网络输入字节流地址，并封装成网络输入字符流
        InputStream socketIn=socket.getInputStream();
        br=new BufferedReader(new InputStreamReader(socketIn,"utf-8"));
 
    }
 
    public void send(String msg){
        //输出字符流，由socket调用系统底层函数，经网卡发送字节流
        pw.println(msg);
        try {
            //进行邮件交互，发送smtp指令之间应该暂停一段时间
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
 
    public String receive(){
        String msg=null;
        try {
            //从网络输入字符流中读取信息，每次只能接受一行信息
            //不够一行时（无行结束符），该语句阻塞
            //直到条件满足，程序往下运行
            msg=br.readLine();
        }catch (IOException e){
            e.printStackTrace();
        }
        return msg;
    }
 
    public void close(){
        try {
            if (socket!=null)
                socket.close();
        }catch (IOException e){
            e.printStackTrace();
        }
    }
}