这是啥状况啊求解答

这是啥情况啊，求解答
Exception in thread "main" java.lang.NullPointerException
at javax.mail.internet.InternetAddress.lengthOfFirstSegment(InternetAddress.java:455)
at javax.mail.internet.InternetAddress.toString(InternetAddress.java:438)
at javax.mail.internet.InternetAddress.toString(InternetAddress.java:402)
at javax.mail.internet.MimeMessage.setAddressHeader(MimeMessage.java:686)
at javax.mail.internet.MimeMessage.setRecipients(MimeMessage.java:565)
at javax.mail.Message.setRecipient(Message.java:353)
at com.dianzhi.util.SimpleMailSender.sendTextMail(SimpleMailSender.java:39)
at com.dianzhi.util.Test.main(Test.java:20)




package com.dianzhi.util;

public class Test {
public static void main(String[] args){   
        //这个类主要是设置邮件   
     MailSenderInfo mailInfo = new MailSenderInfo();    
     mailInfo.setMailServerHost("smtp.163.com");    
     mailInfo.setMailServerPort("25");    
     mailInfo.setValidate(true);    
     mailInfo.setUserName("wangbing_888wang@163.com");    
     mailInfo.setPassword("**");//您的邮箱密码    
     mailInfo.setFromAddress("wangbing_888wang@163.com");    
     mailInfo.setToAddress("879697852@qq.com");    
     mailInfo.setSubject("中国桂花网");    
     mailInfo.setContent("你好");
     mailInfo.setAttachFileNames("ss");
     
        //这个类主要来发送邮件   
     SimpleMailSender sms = new SimpleMailSender();   
         sms.sendTextMail(mailInfo);//发送文体格式    
         //sms.sendHtmlMail(mailInfo);//发送html格式   
   }  


}

------解决方案--------------------
setRecipient接收人空的，.setRecipients(Message.RecipientType.TO, “879697852@qq.com”);