java中javamail发送带附件的邮件实现方法

package mail; 
 
import java.util.* ; 
import java.io.* ; 
import javax.mail.* ; 
import javax.mail.internet.* ; 
import javax.activation.* ; 
public class Mail { 
    //定义发件人、收件人、SMTP服务器、用户名、密码、主题、内容等 
    private String displayName; 
    private String to; 
    private String from; 
    private String smtpServer; 
    private String username; 
    private String password; 
    private String subject; 
    private String content; 
    private boolean ifAuth; //服务器是否要身份认证 
    private String filename=""; 
    private Vector file = new Vector(); //用于保存发送附件的文件名的集合
    
    /**
     * 设置SMTP服务器地址
     */ 
    public void setSmtpServer(String smtpServer){ 
        this.smtpServer=smtpServer; 
    } 
    
    /**
     * 设置发件人的地址
     */ 
    public void setFrom(String from){ 
        this.from=from; 
    } 
    /**
     * 设置显示的名称
     */ 
    public void setDisplayName(String displayName){ 
        this.displayName=displayName; 
    } 
    
    /**
     * 设置服务器是否需要身份认证
     */ 
    public void setIfAuth(boolean ifAuth){ 
        this.ifAuth=ifAuth; 
    } 
    
    /**
     * 设置E-mail用户名
     */ 
    public void setUserName(String username){ 
        this.username=username; 
    } 
    
    /**
     * 设置E-mail密码
     */ 
    public void setPassword(String password){ 
        this.password=password; 
    } 
    
    /**
     * 设置接收者
     */ 
    public void setTo(String to){ 
        this.to=to; 
    } 
    
    /**
     * 设置主题
     */ 
    public void setSubject(String subject){ 
        this.subject=subject; 
    } 
    
    /**
     * 设置主体内容
     */ 
    public void setContent(String content){ 
        this.content=content; 
    } 
    
    /**
     * 该方法用于收集附件名
     */ 
    public void addAttachfile(String fname){ 
        file.addElement(fname); 
    } 
    
    public Mail(){ 
        
    } 
    
    /**
     * 初始化SMTP服务器地址、发送者E-mail地址、用户名、密码、接收者、主题、内容
     */ 
    public Mail(String smtpServer,String from,String displayName,String username,String password,String to,String subject,String content){ 
        this.smtpServer=smtpServer; 
        this.from=from; 
        this.displayName=displayName; 
        this.ifAuth=true; 
        this.username=username; 
        this.password=password; 
        this.to=to; 
        this.subject=subject; 
        this.content=content; 
    } 
    
    /**
     * 初始化SMTP服务器地址、发送者E-mail地址、接收者、主题、内容
     */ 
    public Mail(String smtpServer,String from,String displayName,String to,String subject,String content){ 
        this.smtpServer=smtpServer; 
        this.from=from; 
        this.displayName=displayName; 
        this.ifAuth=false; 
        this.to=to; 
        this.subject=subject; 
        this.content=content; 
    } 
 
    /**
     * 发送邮件
     */ 
    public HashMap send(){ 
        HashMap map=new HashMap(); 
        map.put("state", "success"); 
        String message="邮件发送成功！"; 
        Session session=null; 
        Properties props = System.getProperties(); 
        props.put("mail.smtp.host", smtpServer); 
        if(ifAuth){ //服务器需要身份认证 
            props.put("mail.smtp.auth","true");    
            SmtpAuth smtpAuth=new SmtpAuth(username,password); 
            session=Session.getDefaultInstance(props, smtpAuth);  
        }else{ 
            props.put("mail.smtp.auth","false"); 
            session=Session.getDefaultInstance(props, null); 
        } 
        session.setDebug(true); 
        Transport trans = null;   
        try { 
            Message msg = new MimeMessage(session);  
            try{ 
                Address from_address = new InternetAddress(from, displayName); 
                msg.setFrom(from_address); 
            }catch(java.io.UnsupportedEncodingException e){ 
                e.printStackTrace(); 
            } 
            InternetAddress[] address={new InternetAddress(to)}; 
            msg.setRecipients(Message.RecipientType.TO,address); 
            msg.setSubject(subject); 
            Multipart mp = new MimeMultipart(); 
            MimeBodyPart mbp = new MimeBodyPart(); 
            mbp.setContent(content.toString(), "text/html;charset=gb2312"); 
            mp.addBodyPart(mbp);   
            if(!file.isEmpty()){//有附件 
                Enumeration efile=file.elements(); 
                while(efile.hasMoreElements()){  
                    mbp=new MimeBodyPart(); 
                    filename=efile.nextElement().toString(); //选择出每一个附件名 
                    FileDataSource fds=new FileDataSource(filename); //得到数据源 
                    mbp.setDataHandler(new DataHandler(fds)); //得到附件本身并至入BodyPart 
                    mbp.setFileName(fds.getName());  //得到文件名同样至入BodyPart 
                    mp.addBodyPart(mbp); 
                }   
                file.removeAllElements();     
            }  
            msg.setContent(mp); //Multipart加入到信件 
            msg.setSentDate(new Date());     //设置信件头的发送日期 
            //发送信件 
            msg.saveChanges();  
            trans = session.getTransport("smtp"); 
            trans.connect(smtpServer, username, password); 
            trans.sendMessage(msg, msg.getAllRecipients()); 
            trans.close(); 
            
        }catch(AuthenticationFailedException e){    
             map.put("state", "failed"); 
             message="邮件发送失败！错误原因：\n"+"身份验证错误!"; 
             e.printStackTrace();  
        }catch (MessagingException e) { 
             message="邮件发送失败！错误原因：\n"+e.getMessage(); 
             map.put("state", "failed"); 
             e.printStackTrace(); 
             Exception ex = null; 
             if ((ex = e.getNextException()) != null) { 
                 System.out.println(ex.toString()); 
                 ex.printStackTrace(); 
             }  
        } 
        //System.out.println("\n提示信息:"+message); 
        map.put("message", message); 
        return map; 
    } 
}

package mail; 
 
public class SmtpAuth extends javax.mail.Authenticator {  
    private String username,password;  
 
    public SmtpAuth(String username,String password){  
        this.username = username;   
        this.password = password;   
    }  
    protected javax.mail.PasswordAuthentication getPasswordAuthentication() {  
        return new javax.mail.PasswordAuthentication(username,password);
    }  
}