一个关于Socket问题

[qbyuji]

服务机程序如下:
import java.io.*;
import java.net.*;
public class TestServer {
public static void main(String args[]){
try{
ServerSocket portnum = new ServerSocket(7000);

Socket clientSocket = portnum.accept();
DataInputStream dis = new DataInputStream(clientSocket.getInputStream());
new ServerReader(dis).start();
}catch(IOException e){
e.printStackTrace();
}
}
static class ServerReader extends Thread{
DataInputStream dis;
public ServerReader(DataInputStream dis){
this.dis = dis;
}

public void run(){
String info;
try{
while(true){
info = dis.readUTF();
System.out.println(info);
}
} catch(IOException he){
he.printStackTrace();
}
}
}
}




客户机程序如下:
import java.io.*;
import java.net.*;
public class TestClient {
public static void main(String args[]){
try {
Socket s1 = new Socket("127.0.0.1" ,7000);
DataOutputStream os= new DataOutputStream(s1.getOutputStream());
InetAddress host = null;
os.writeUTF("客户主机名为:" +host.getHostName() );
}catch(IOException e){
e.printStackTrace();
}
}
}


想在服务机打印出客户机的主机名 运行后却得不到想要的结果 本人是菜鸟 不知道上面程序问题出现在哪里? 谢谢指教....

[云上飞翔]

答：已通过测试的程序代码参考如下：你自己再比较读一读吧

//服务器
import java.io.*; 
import java.net.*; 
public class TestServer { 
public static void main(String args[]){ 
try{ 
ServerSocket portnum = new ServerSocket(7000); 

Socket clientSocket = portnum.accept(); 
BufferedReader dis = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())); 
new ServerReader(dis).start(); 
}catch(IOException e){ 
e.printStackTrace(); 
} 
} 
static class ServerReader extends Thread{ 
BufferedReader dis; 
public ServerReader(BufferedReader dis){ 
this.dis = dis; 
} 

public void run(){ 
String info; 
try{ 
//while(true)
{ 
info = dis.readLine(); 
System.out.println(info); 
} 
} catch(IOException he){ 
he.printStackTrace(); 
} 
} 
} 
} 
//以下是客户机
import java.io.*; 
import java.net.*; 
public class TestClient { 
public static void main(String args[]){ 
try { 
Socket s1 = new Socket("127.0.0.1" ,7000); 
PrintWriter os= new PrintWriter(s1.getOutputStream()); 
InetAddress host = null; 
os.println("客户主机名为:" +host.getLocalHost().getHostName() ); 
os.flush();
os.close();
}catch(IOException e){ 
e.printStackTrace(); 
} 
} 
}