javamail发邮件附件是中文出现乱码？
我这有一个JAVAmail发送邮件的程序如下，为什么发送附件的名字为中文的时候，在邮箱中收到的附件名会出现乱码呢应该怎么解决谢谢了。
代码如下:下面代码粘贴过去就可以执行，改下邮箱名和密码

package com.res.mng;



/**
* @author Zhangkun aistill@msn.com
* @version 1.0
*/

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import java.util.Date;
import javax.activation.*;
import java.io.*;


public class sendMail {

private MimeMessage mimeMsg; //MIME邮件对象

private Session session; //邮件会话对象
private Properties props; //系统属性
private boolean needAuth = false; //smtp是否需要认证

private String username = ""; //smtp认证用户名和密码
private String password = "";

private Multipart mp; //Multipart对象,邮件内容,标题,附件等内容均添加到其中后再生成MimeMessage对象



/**
* 
*/


public sendMail(String smtp){
setSmtpHost(smtp);
createMimeMessage();
}



/**
* @param hostName String
*/
public void setSmtpHost(String hostName) {
System.out.println("设置系统属性：mail.smtp.host = "+hostName);
if(props == null)props = System.getProperties(); //获得系统属性对象

props.put("mail.smtp.host",hostName); //设置SMTP主机
}


/**
* @return boolean
*/
public boolean createMimeMessage()
{
try{
System.out.println("准备获取邮件会话对象！");
session = Session.getDefaultInstance(props,null); //获得邮件会话对象
}
catch(Exception e){
System.err.println("获取邮件会话对象时发生错误！"+e);
return false;
}

System.out.println("准备创建MIME邮件对象！");
try{
mimeMsg = new MimeMessage(session); //创建MIME邮件对象
mp = new MimeMultipart();

return true;
}
catch(Exception e){
System.err.println("创建MIME邮件对象失败！"+e);
return false;
}
}



/**
* @param need boolean
*/
public void setNeedAuth(boolean need) {
System.out.println("设置smtp身份认证：mail.smtp.auth = "+need);
if(props == null)props = System.getProperties();

if(need){
props.put("mail.smtp.auth","true");
}else{
props.put("mail.smtp.auth","false");
}
}



/**
* @param name String
* @param pass String
*/
public void setNamePass(String name,String pass) {
username = name;
password = pass;
}


/**
* @param mailSubject String
* @return boolean
*/
public boolean setSubject(String mailSubject) {
System.out.println("设置邮件主题！");
try{
mimeMsg.setSubject(mailSubject);
return true;
}
catch(Exception e) {
System.err.println("设置邮件主题发生错误！");
return false;
}
}



/**
* @param mailBody String
*/
public boolean setBody(String mailBody) {
try{
BodyPart bp = new MimeBodyPart();
bp.setContent("<meta http-equiv=Content-Type content=text/html; charset=gbk>"+mailBody,"text/html;charset=gbk");
mp.addBodyPart(bp);

return true;
}
catch(Exception e){
System.err.println("设置邮件正文时发生错误！"+e);
return false;
}
}


/**
* @param name String
* @param pass String
*/
public boolean addFileAffix(String filename) {

System.out.println("增加邮件附件："+filename);

try{
BodyPart bp = new MimeBodyPart();
FileDataSource fileds = new FileDataSource(filename);
bp.setDataHandler(new DataHandler(fileds));
bp.setFileName(fileds.getName());
System.out.println("得到名:"+bp.getFileName());
mp.addBodyPart(bp);

return true;
}
catch(Exception e){
System.err.println("增加邮件附件："+filename+"发生错误！"+e);
return false;
}
}



/**
* @param name String
* @param pass String