Java程序设计实用教程习题答案(7)

InetAddress localHost = InetAddress.getLocalHost(); String ipAdd = localHost.getHostAddress(); textField1.setText(ipAdd); }catch(Exception ex){

textField1.setText(\ } }

public static void main(String[] args) { getIpAddress frm=new getIpAddress(); frm.setVisible(true); } }

4．采用套接字的连接方式编写一个程序，允许客户向服务器提出一个文件的名字。如果文件存在就把文件的内容发送回客户，否则指出文件不存在。

假设文本文件score.txt的文件内容如下：

VB Java C++ 90 87 70 91 84 88 92 81 90

服务器端的运行结果如图11-9所示。

图11-9

客户端的运行结果如图11-10所示。

图11-10

程序参考代码如下：

? 服务器端程序 import java.net.*; import java.io.*;

public class SocketServer {

public static final int port=8000;

public static void main(String[] args) { String str; try{

ServerSocket server=new ServerSocket(port); System.out.println(\ Socket socket=server.accept();

System.out.println(\ InputStream fln=socket.getInputStream();

OutputStream fOut=socket.getOutputStream();

InputStreamReader isr=new InputStreamReader(fln); BufferedReader in=new BufferedReader(isr); PrintStream out=new PrintStream(fOut); File sourceFile;

BufferedReader source;

System.out.println(\等待客户端的消息...\ str=in.readLine();

System.out.println(\客户端：\ sourceFile=new File(str);

System.out.println(\等待客户发送：\ try{

source=new BufferedReader(new FileReader(sourceFile)); while((str=source.readLine())!=null) {out.println(str);} out.println(\

}catch(FileNotFoundException e) {

System.out.println(\文件不存在:\ out.println(\ }

socket.close(); server.close(); }catch(Exception e){

System.out.println(\异常：\ } } } ? 客户端程序 import java.net.*; import java.io.*;

public class ServerClient {

public static void main(String[] args) { String str; try{

InetAddress addr=InetAddress.getByName(\ Socket socket=new Socket(addr,8000); System.out.println(\

InputStream fIn=socket.getInputStream(); OutputStream fOut=socket.getOutputStream();

InputStreamReader isr=new InputStreamReader(fIn); BufferedReader in=new BufferedReader(isr); PrintStream out=new PrintStream(fOut);

InputStreamReader userisr=new InputStreamReader(System.in); BufferedReader userin=new BufferedReader(userisr); System.out.print(\发送字符串:\ str=userin.readLine(); out.println(str);

System.out.println(\等待获取服务器字符串\ if(str.equalsIgnoreCase(\ {

System.out.println(str);

throw new FileNotFoundException(\文件不存在异常!\ }

while(true){

str=in.readLine();

if(str.equals(\ System.out.println(str); }

socket.close(); }

catch(Exception e){

System.out.println(\异常：\ } } }