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使用缓冲的读取器和套接字

[英]Using Buffered reader and Socket

我编写了这个简单的Java程序,该程序连接到Internic服务器并返回域详细信息。 但是,我面临一个奇怪的问题。 我听起来可能很蠢,但这是程序!

import java.io.*;
import java.net.*;
public class SocketTest {
    public static void main(String[] args) {
        String hostName;
        int i = 0;

        try {                  
            Socket socketClient = new Socket("whois.internic.net", 43);
            BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
            InputStream in = socketClient.getInputStream();
            OutputStream out = socketClient.getOutputStream();
            System.out.println("Please Enter the Host Name!!");
            hostName = bf.readLine();      
            hostName = hostName + "\n";
            byte[] buf = hostName.getBytes();
            out.write(buf);

            while((i = in.read()) != -1) {
                System.out.print((char)i);
            }

            socketClient.close();
        } catch(UnknownHostException uht) {
            System.out.println("Host Error");
        } catch(IOException ioe) {
            System.out.println("IO Error " + ioe);
        } catch(Exception e) {
            System.out.println("Exception " + e);
        }
    }
}

该程序运行良好,没有任何运行时错误,但是当我尝试在最后一块try块中尝试从Internic服务器打印结果时,它没有显示任何输出。 我尝试重新排列代码,发现如果在创建套接字流后放置bf.readLine() ,则没有输出。 但是,如果将其放置在套接字创建之前(在main方法的开始处),程序将显示预期的输出。

是否存在流冲突? 我是Java网络方面的新手。 解决方案可能很明显,但我听不懂! 请帮我!!!

将域发送到输出流后,将输入流的初始化移动。...这对我本地有效:

import java.io.*;
import java.net.*;

public class SocketTest {
    public static void main(String[] args) {
        String hostName;
        int i = 0;
        try {
            Socket socketClient = new Socket("whois.internic.net", 43);
            BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

            OutputStream out = socketClient.getOutputStream();
            System.out.println("Please Enter the Host Name!!");
            hostName = bf.readLine();
            hostName = hostName + "\n";
            byte[] buf = hostName.getBytes();
            out.write(buf);

            InputStream in = socketClient.getInputStream();
            while ((i = in.read()) != -1) {
                System.out.print((char) i);
            }
            in.close();
            out.close();
            socketClient.close();

        } catch (UnknownHostException uht) {
            System.out.println("Host Error");
        } catch (IOException ioe) {
            System.out.println("IO Error " + ioe);
        } catch (Exception e) {
            System.out.println("Exception " + e);
        }
    }
}

输出:

Please Enter the Host Name!!
yahoo.com

Whois Server Version 2.0

Domain names in the .com and .net domains can now be registered
with many different competing registrars. Go to http://www.internic.net
for detailed information.

YAHOO.COM.ZZZZZZZ.GET.ONE.MILLION.DOLLARS.AT.WWW.UNIMUNDI.COM
YAHOO.COM.ZZZZZZ.MORE.INFO.AT.WWW.BEYONDWHOIS.COM
....Whole bunch more

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