在 Java 中实现 SIP 通话可以使用 SIP API,比如 SIP API for Java (SIPServer API) 或者 MJSip。
使用 SIP API for Java (SIPServer API) 可以这样写代码:
``` import java.io.IOException; import java.net.InetAddress; import javax.sip.ClientTransaction; import javax.sip.Dialog; import javax.sip.DialogState; import javax.sip.DialogTerminatedEvent; import javax.sip.IOExceptionEvent; import javax.sip.ListeningPoint; import javax.sip.RequestEvent; import javax.sip.ResponseEvent; import javax.sip.ServerTransaction; import javax.sip.SipFactory; import javax.sip.SipListener; import javax.sip.SipProvider; import javax.sip.SipStack; import javax.sip.TimeoutEvent; import javax.sip.TransactionTerminatedEvent; import javax.sip.address.Address; import javax.sip.address.AddressFactory; import javax.sip.address.SipURI; import javax.sip.header.CSeqHeader; import javax.sip.header.CallIdHead