java 群发邮件 保证解决的办法

示例中需要用到两个包：mail.jar和activation.jar，其下载地址为：
http://java.sun.com/products/javamail/downloads/index.html
http://java.sun.com/javase/technologies/desktop/javabeans/jaf/downloads/index.html

下载后解压，将mail.jar和activation.jar放到project里的lib文件夹中，为其配置环境变量，或在myEclipse里的"Java Build Path"中将其添加到"Libraries"。

project里有三个类：入口类（TestJavaMail）、邮件信息类（MailBean）和发送邮件类（SendMail）

MailBean.java

package test3;

import java.util.Vector;

public class MailBean ...{

    private String to;                                // 收件人
    private String from;                            // 发件人
    private String host;                            // SMTP主机
    private String username;                        // 发件人的用户名
    private String password;                        // 发件人的密码
    private String subject;                            // 邮件主题
    private String content;                            // 邮件正文
    Vector<String> file;                            // 多个附件
    private String filename;                        // 附件的文件名
    
    public String getTo() ...{
        return to;
    }

    public void setTo(String to) ...{
        this.to = to;
    }

    public String getFrom() ...{
        return from;
    }

    public void setFrom(String from) ...{
        this.from = from;
    }

    public String getHost() ...{
        return host;
    }

    public void setHost(String host) ...{
        this.host = host;
    }

    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 String getSubject() ...{
        return subject;
    }

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

    public String getContent() ...{
        return content;
    }

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

    public String getFilename() ...{
        return filename;
    }

    public void setFilename(String filename) ...{
        this.filename = filename;
    }

    public Vector<String> getFile()...{
        return file;
    }
    
    public void attachFile(String fileName) ...{
        if(file == null)
            file = new Vector<String>();
        file.addElement(fileName);
    }
}
 

SendMail.java

package test3;

import java.util.Date;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Vector;

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;

public class SendMail ...{

    public String toChinese(String text) ...{
        try ...{
            text = MimeUtility.encodeText(new String(text.getBytes(), "GB2312"), "GB2312", "B");
        } catch (Exception e) ...{
            e.printStackTrace();
        }
        return text;
    }


    public boolean sendMail(MailBean mb) ...{
        String host = mb.getHost();
        final String username = mb.getUsername();
        final String password = mb.getPassword();
        String from = mb.getFrom();
        String to = mb.getTo();
        String subject = mb.getSubject();
        String content = mb.getContent();
        String fileName = mb.getFilename();
        Vector<String> file = mb.getFile();
        
        
        Properties props = System.getProperties();
        props.put("mail.smtp.host", host);                // 设置SMTP的主机
        props.put("mail.smtp.auth", "true");            // 需要经过验证
        
        Session session = Session.getInstance(props, new Authenticator() ...{
            public PasswordAuthentication getPasswordAuthentication() ...{
                return new PasswordAuthentication(username, password);
            }
        });

        try ...{
            MimeMessage msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress(from));
            InternetAddress[] address = ...{new InternetAddress(to)};
            msg.setRecipients(Message.RecipientType.TO, address);
            msg.setSubject(toChinese(subject));

            Multipart mp = new MimeMultipart();
            MimeBodyPart mbpContent = new MimeBodyPart();
            mbpContent.setText(content);
            mp.addBodyPart(mbpContent);

            /**//*    往邮件中添加附件    */
            Enumeration<String> efile = file.elements();
            while (efile.hasMoreElements()) ...{
                MimeBodyPart mbpFile = new MimeBodyPart();
                fileName = efile.nextElement().toString();
                FileDataSource fds = new FileDataSource(fileName);
                mbpFile.setDataHandler(new DataHandler(fds));
                mbpFile.setFileName(toChinese(fds.getName()));
                mp.addBodyPart(mbpFile);
            }

            msg.setContent(mp);
            msg.setSentDate(new Date());
            Transport.send(msg);
            
        } catch (MessagingException me) ...{
            me.printStackTrace();
            return false;
        }
        return true;
    }

}

TestJavaMail.java

package test3;

public class TestJavaMail ...{

    public static void main(String[] args) ...{
        
        MailBean mb = new MailBean();
        mb.setHost("smtp.163.com");                        // 设置SMTP主机(163)，若用126，则设为：smtp.126.com
        mb.setUsername("linyiteng1220");                // 设置发件人邮箱的用户名
        mb.setPassword("******");                        // 设置发件人邮箱的密码，需将*号改成正确的密码
        mb.setFrom("[e-mail]");            // 设置发件人的邮箱
        mb.setTo("[e-mail]");                // 设置收件人的邮箱
        mb.setSubject("测试_JavaMail");                    // 设置邮件的主题
        mb.setContent("本邮件中包含三个附件，请检查！");        // 设置邮件的正文

        mb.attachFile("E:\工作报告(林乙腾).doc");            // 往邮件中添加附件
        mb.attachFile("E:\test.txt");
        mb.attachFile("E:\test.xls");
        
        SendMail sm = new SendMail();
        System.out.println("正在发送邮件...");
        
        if(sm.sendMail(mb))                                // 发送邮件
            System.out.println("发送成功!");
        else
            System.out.println("发送失败!");
    }
    
}
如果你用myEclipse进行开发的话，运行时可能会出现以下的错误：
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/mail/util/LineInputStream

解决方法：移除myEclipse自带的EE包。
                    但你可能还需要用到EE包里的servlet相关类，那可以从Tomcat的lib文件夹中复制servlet-api.jar到project中，用它来代替EE包，一切OK！

另外，个人测试时发现无法通过新注册的网易邮箱来发邮件，以前旧的就没有问题，不知道是什么原因。

如果要通过gmail发邮件的话，请在代码Properties props = System.getProperties();后再添加以下两行代码：

      props.put("mail.transport.protocol", "smtp");
      props.put("mail.smtp.starttls.enable","true");

搞定！

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