java使用Socket实现SMTP协议发送邮件

本文实例为大家分享了java 利用Socket实现SMTP协议发送邮件的具体代码，供大家参考，具体内容如下

package mail;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Reader;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.codec.binary.Base64;

public class Mail {

public static void main(String[] args) throws IOException {
   Mail mail = new Mail();
   mail.setSmtpServer("smtp.qq.com");
   mail.setFromMail("1344364****@qq.com");
   mail.addToMail("105648****@qq.com");
   mail.addToMail("long*****@sina.com");
   mail.setUserName("134364****");
   mail.setPassword("*************");
   mail.setSubject("测试邮件");
   mail.setContent("<h1>你好</h1><br/><img src=\"https://www.baidu.com/img/baidu_jgylogo3.gif?v=39549282.gif\" />");
   mail.setShowLog(true);
   mail.send();
   System.out.println("程序结束");
 }

/** 邮件主题 **/
 private String subject;
 /** 从此地址发出 **/
 private String fromMail;
 /** 用户名 **/
 private String userName;
 /** 登录密码 **/
 private String password;
 /** SMTP 服务器地址 **/
 private String smtpServer;
 /** SMTP 服务器端口（默认：25） **/
 private int smtpPort = 25;
 /** 发送到 toMail 中的所有地址 **/
 private List<String> toMail;
 /** 邮件内容 **/
 private String content;
 /** 是否显示日志 **/
 private boolean showLog;

public void addToMail(String mail) {
   if (toMail == null)
     toMail = new ArrayList<String>();
   toMail.add(mail);
 }

public void send() {
   if (smtpServer == null) {
     throw new RuntimeException("smtpServer 不能为空");
   }
   if (userName == null) {
     throw new RuntimeException("userName 不能为空");
   }
   if (password == null) {
     throw new RuntimeException("password 不能为空");
   }
   if (fromMail == null) {
     throw new RuntimeException("fromMail 不能为空");
   }
   if (toMail == null || toMail.isEmpty()) {
     throw new RuntimeException("toMail 不能为空");
   }
   if (content == null || toMail.isEmpty()) {
     throw new RuntimeException("content 不能为空");
   }

Socket socket = null;
   InputStream in = null;
   OutputStream out = null;
   try {
     socket = new Socket(smtpServer, smtpPort);
     socket.setSoTimeout(3000);
     in = socket.getInputStream();
     out = socket.getOutputStream();
   } catch (IOException e) {
     throw new RuntimeException("连接到 " + smtpServer + ":" + smtpPort + " 失败", e);
   }

BufferedReaderProxy reader = new BufferedReaderProxy(new InputStreamReader(in), showLog);
   PrintWriterProxy writer = new PrintWriterProxy(out, showLog);

reader.showResponse();
   writer.println("HELO " + smtpServer);
   reader.showResponse();
   writer.println("AUTH LOGIN");
   reader.showResponse();
   writer.println(new String(Base64.encodeBase64(userName.getBytes())));
   reader.showResponse();
   writer.println(new String(Base64.encodeBase64(password.getBytes())));
   reader.showResponse();
   writer.println("MAIL FROM:" + fromMail);
   reader.showResponse();
   for (String mail : toMail) {
     writer.println("RCPT TO:" + mail);
     reader.showResponse();
   }
   writer.println("DATA");
   writer.println("Content-Type:text/html");
   if (subject != null) {
     writer.println("Subject:" + subject);
   }
   writer.println("From:" + fromMail);
   writer.print("To:");
   for (String mail : toMail) {
     writer.print(mail + "; ");
   }
   writer.println();
   writer.println();
   writer.println(content);
   writer.println(".");
   reader.showResponse();
   writer.println("QUIT");
   reader.showResponse();
   try {
     socket.close();
   } catch (IOException e) {
     System.err.println("发送邮件完成，关闭 Socket 出错：" + e.getMessage());
   }
 }

public String getSubject() {
   return subject;
 }

public void setSubject(String subject) {
   this.subject = subject;
 }

public String getFromMail() {
   return fromMail;
 }

public void setFromMail(String fromMail) {
   this.fromMail = fromMail;
 }

public String getSmtpServer() {
   return smtpServer;
 }

public void setSmtpServer(String smtpServer) {
   this.smtpServer = smtpServer;
 }

public int getSmtpPort() {
   return smtpPort;
 }

public void setSmtpPort(int smtpPort) {
   this.smtpPort = smtpPort;
 }

public String getContent() {
   return content;
 }

public void setContent(String content) {
   this.content = content;
 }

public List<String> getToMail() {
   return toMail;
 }

public void setToMail(List<String> toMail) {
   this.toMail = toMail;
 }

public String getUserName() {
   return userName;
 }

public void setUserName(String userName) {
   this.userName = userName;
 }

public String getPassword() {
   return password;
 }

public void setPassword(String password) {
   this.password = password;
 }

public boolean getShowLog() {
   return showLog;
 }

public void setShowLog(boolean showLog) {
   this.showLog = showLog;
 }

static class PrintWriterProxy extends PrintWriter {
   private boolean showRequest;

public PrintWriterProxy(OutputStream out, boolean showRequest) {
     super(out, true);
     this.showRequest = showRequest;
   }

@Override
   public void println() {
     if (showRequest)
       System.out.println();
     super.println();
   }

public void print(String s) {
     if (showRequest)
       System.out.print(s);
     super.print(s);
   }
 }

static class BufferedReaderProxy extends BufferedReader {
   private boolean showResponse = true;

public BufferedReaderProxy(Reader in, boolean showResponse) {
     super(in);
     this.showResponse = showResponse;
   }

public void showResponse() {
     try {
       String line = readLine();
       String number = line.substring(0, 3);
       int num = -1;
       try {
         num = Integer.parseInt(number);
       } catch (Exception e) {
       }
       if (num == -1) {
         throw new RuntimeException("响应信息错误 : " + line);
       } else if (num >= 400) {
         throw new RuntimeException("发送邮件失败 : " + line);
       }
       if (showResponse) {
         System.out.println(line);
       }
     } catch (IOException e) {
       System.out.println("获取响应失败");
     }
   }

}
}