第一次運行正確,之后就抱這個錯

java.net.ConnectException: Connection refused: connect
?at java.net.DualStackPlainSocketImpl.connect0(Native Method)
?at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
?at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:337)
?at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:198)
?at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:180)
?at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
?at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
?at java.net.Socket.connect(Socket.java:579)
?at java.net.Socket.connect(Socket.java:528)
?at java.net.Socket.<init>(Socket.java:425)
?at java.net.Socket.<init>(Socket.java:208)
?at com.mr.Client.main(Client.java:15)