採用apache的commons-email包發送郵件死鎖

採用apache的commons-email包發郵件時候，程序卡住停頓了，使用jstack命令查看棧信息如下：

   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at com.sun.mail.util.TraceInputStream.read(TraceInputStream.java:110)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
    - locked <0x00000007fb055378> (a java.io.BufferedInputStream)
    at com.sun.mail.util.LineInputStream.readLine(LineInputStream.java:88)
    at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:1589)
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1369)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:412)
    at javax.mail.Service.connect(Service.java:288)
    - locked <0x00000007fb0515d8> (a com.sun.mail.smtp.SMTPTransport)
    at javax.mail.Service.connect(Service.java:169)
    at javax.mail.Service.connect(Service.java:118)
    at javax.mail.Transport.send0(Transport.java:188)
    at javax.mail.Transport.send(Transport.java:118)
    at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1232)
    at org.apache.commons.mail.Email.send(Email.java:1267)
    at com.renren.zhaopin.mail.util.MailPostUtil.postMail(MailPostUtil.java:61)
    at com.renren.zhaopin.mail.util.MailPostUtil.postMail(MailPostUtil.java:39)
    at com.renren.xoa2.xiaozhao.mail.service.BaskGroundService$Consumer.waitConsumerEmail(BaskGroundService.java:212)
    at com.renren.xoa2.xiaozhao.mail.service.BaskGroundService$Consumer.run(BaskGroundService.java:152)
    at java.lang.Thread.run(Thread.java:662)

通過查找發現，原來是一臺postfix郵件服務器掛了，導致一直佔用io，而連接的時候，未設置超時等信息所致。

解決方法：

1）找到掛掉的服務器，去掉即可。

或

2）完善發送程序，發送代碼中加入以下代碼：

 email.setSocketTimeout(60*1000);
 email.setSocketConnectionTimeout(60*1000);