java方面的， 应用TCP编程， 完成一个多线程版的服务端 ，当Client访问时 ，返回当前访问的时间。。求编码

这个需要多线程么？把服务端搞成常驻内存的就好了吧。比如while。下面是我刚给你写的测试代码，仅供参考：
客户端：
static Socket server;
public static void main(String[] args) throws Exception {
InetAddress address = InetAddressgetByName("134132207228");
server = new Socket(address, 4567);

PrintWriter out = new PrintWriter(servergetOutputStream());
String str = "发送内容";
Systemoutprintln("client send:"+str);
outprintln(str);
outflush();
BufferedReader wt = new BufferedReader(new InputStreamReader(servergetInputStream()));
str = wtreadLine();
Systemoutprintln("client receive:"+str);

wtclose();
outclose();
serverclose();
}
服务端：
static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

public static void main(String[] args) throws IOException {
ServerSocket server = new ServerSocket(4567);
while(true){
Socket client = serveraccept();

BufferedReader in = new BufferedReader(new InputStreamReader(clientgetInputStream()));
String str = inreadLine();
Systemoutprintln("server receive:"+str);

PrintWriter out = new PrintWriter(clientgetOutputStream());
str = "来自服务器:"+getCurrentDateTimeStr();
outprintln(str);
outflush();
Systemoutprintln(str);

outclose();
inclose();
clientclose();
}
}

public static String getCurrentDateTimeStr(){
Calendar cal = CalendargetInstance();
return getFormatedTime(calgetTime());
}

public static String getFormatedTime(Date date) {
return dateFormatformat(date);
}

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