多線程的第一次運行沒問題，第二次就開始報錯了

java.net.SocketException: Connection reset

at java.net.SocketInputStream.read(Unknown Source)

at java.net.SocketInputStream.read(Unknown Source)

at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)

at sun.nio.cs.StreamDecoder.implRead(Unknown Source)

at sun.nio.cs.StreamDecoder.read(Unknown Source)

at java.io.InputStreamReader.read(Unknown Source)

at java.io.BufferedReader.fill(Unknown Source)

at java.io.BufferedReader.readLine(Unknown Source)

at java.io.BufferedReader.readLine(Unknown Source)

at com.MyChatSystem.server.Client.main(Client.java:30)