Java实现Socket之WhoisClient

Java实现Socket之WhoisClient

代码内容

代码实现

/* WhoisClient.java */
import java.io.*;
import java.net.*;

public class WhoisClient {
public static void main(String[] args) {
BufferedReader systemIn = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the domain names. Enter \"exit\" to quit.");
try {
while (true) {
/* 输入流提示控制 */
System.out.print("> ");
String host = (args.length > 0) ? args[0] : systemIn.readLine();
if (host.isEmpty()) {
continue;
} else if (host.equalsIgnoreCase("exit")) {
break;
}
whois(host);
if (args.length > 0)
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}

private static void whois(String host) {
try {
/* 设置服务器地址和端口号 */
InetAddress server = InetAddress.getByName("whois.markmonitor.com");
int port = 43;
/* 建立Socket连接 */
Socket socket = new Socket(server, port);
/* 写入发送消息到Socket */
PrintWriter out = new PrintWriter(socket.getOutputStream());
out.println(host);
out.flush();
/* 从Socket读取消息 */
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
/* 格式化输出 */
StringBuilder ret = new StringBuilder();
String line;
while ((line = in.readLine()) != null) {
ret.append(line + "\r\n");
}
/* 安全关闭Socket */
socket.close();
/* 结果输出判断 */
if (ret.toString().trim().isEmpty()) {
System.out.println("该域名不在whois上注册");
} else {
System.out.println(ret.toString());
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

运行截图