我得到了这个例外:
javax.mail.MessagingException: Unknown SMTP host: server.gmail.com;
nested exception is:
java.net.UnknownHostException: server.gmail.com
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1280)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:370)
at javax.mail.Service.connect(Service.java:275)
at javax.mail.Service.connect(Service.java:156)
at javax.mail.Service.connect(Service.java:105)
at javax.mail.Transport.send0(Transport.java:168)
at javax.mail.Transport.send(Transport.java:98)
at com.SimpleSendEmail.main(SimpleSendEmail.java:33)
Caused by: java.net.UnknownHostException: server.gmail.com
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:177)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:232)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:189)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1250)
... 7 more
我还包含了所需的 jar 文件。请帮我解决这个异常。