使用socket连接gmail并发送gmail，但不起作用答案

【问题标题】：Using socket to connet gmail and send gmail, but not work使用socket连接gmail并发送gmail，但不起作用
【发布时间】：2017-03-08 09:37:01
【问题描述】：

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;    
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class SMTPDemo {

  public static void main(String args[]) throws IOException,
      UnknownHostException {
    String msgFile = "file.txt";
    String from = "java2s@java2s.com";
    String to = "yourEmail@yourServer.com";
    String mailHost = "yourHost";
    SMTP mail = new SMTP(mailHost);
    if (mail != null) {
      if (mail.send(new FileReader(msgFile), from, to)) {
        System.out.println("Mail sent.");
          } else {
        System.out.println("Connect to SMTP server failed!");
      }
    }
    System.out.println("Done.");
  }

  static class SMTP {
    private final static int SMTP_PORT = 25;

    InetAddress mailHost;

    InetAddress localhost;

    BufferedReader in;

    PrintWriter out;

    public SMTP(String host) throws UnknownHostException {
      mailHost = InetAddress.getByName(host);
      localhost = InetAddress.getLocalHost();
      System.out.println("mailhost = " + mailHost);
      System.out.println("localhost= " + localhost);
      System.out.println("SMTP constructor done\n");
    }

    public boolean send(FileReader msgFileReader, String from, String to)
        throws IOException {
      Socket smtpPipe;
      InputStream inn;
      OutputStream outt;
      BufferedReader msg;
      msg = new BufferedReader(msgFileReader);
      smtpPipe = new Socket(mailHost, SMTP_PORT);
      if (smtpPipe == null) {
        return false;
      }
      inn = smtpPipe.getInputStream();
      outt = smtpPipe.getOutputStream();
      in = new BufferedReader(new InputStreamReader(inn));
      out = new PrintWriter(new OutputStreamWriter(outt), true);
      if (inn == null || outt == null) {
        System.out.println("Failed to open streams to socket.");
        return false;
      }
      String initialID = in.readLine();
      System.out.println(initialID);
      System.out.println("HELO " + localhost.getHostName());
      out.println("HELO " + localhost.getHostName());
      String welcome = in.readLine();
      System.out.println(welcome);
      System.out.println("MAIL From:<" + from + ">");
      out.println("MAIL From:<" + from + ">");
      String senderOK = in.readLine();
      System.out.println(senderOK);
      System.out.println("RCPT TO:<" + to + ">");
      out.println("RCPT TO:<" + to + ">");
      String recipientOK = in.readLine();
      System.out.println(recipientOK);
      System.out.println("DATA");
      out.println("DATA");
      String line;
      while ((line = msg.readLine()) != null) {
        out.println(line);
      }
      System.out.println(".");
      out.println(".");
      String acceptedOK = in.readLine();
      System.out.println(acceptedOK);
      System.out.println("QUIT");
      out.println("QUIT");
      return true;
    }
  }
}

我想了解如何使 smtp 服务器使用套接字。我在this site 上找到了这个示例代码。

当我在 Eclipse 中编写此代码并编译但 socekt smtpPipe 是错误的。 Eclipse 错误信息：

资源泄漏：'smtpPipe 永远不会关闭'。

我不知道如何解决这个问题。

【问题讨论】：

标签： java sockets server smtp gmail

【解决方案1】：

Eclipse 错误消息：资源泄漏：'smtpPipe 永远不会关闭'

它说你没有关闭资源smtpPipe。推荐的做法是在不再需要资源时关闭它。您可以通过调用smtpPipe.close() 方法来实现这一点。一种方法是将代码包装在 try 和 finally 块周围。阅读有关 finally 块 here 的更多信息。

例子：

try {
    ....
    smtpPipe = new Socket(mailHost, SMTP_PORT);
    ....

} finally {
   if (smtpPipe != null)
      smtpPipe.close();
}

另外，对InputStream 和OutputStream 等其他资源使用类似的方法

【讨论】：