ftp 下载文件时出现错误!

akucindaim 2008-09-04 11:13:41

package socket.FTP;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.net.ServerSocket;
import java.net.Socket;
/**
* 服务器端
* @author lake
*
*/
public class Server {
int port = 21;

void start() {
Socket s = null;
try {
ServerSocket ss = new ServerSocket(port);
while (true) {
// 选择进行传输的文件
String filePath = "E:\\ftp.txt";
File fi = new File(filePath);

System.out.println("文件长度:" + (int) fi.length());

// public Socket accept() throws
// IOException侦听并接受到此套接字的连接。此方法在进行连接之前一直阻塞。

s = ss.accept();
System.out.println("建立socket链接");
DataInputStream dis = new DataInputStream(
new BufferedInputStream(s.getInputStream()));
dis.readByte();

DataInputStream fis = new DataInputStream(
new BufferedInputStream(new FileInputStream(filePath)));
DataOutputStream ps = new DataOutputStream(s.getOutputStream());
//将文件名及长度传给客户端。这里要真正适用所有平台，例如中文名的处理，还需要加工。
ps.writeUTF(fi.getName());
ps.flush();
ps.writeLong((long) fi.length());
ps.flush();

int bufferSize = 8192;
byte[] buf = new byte[bufferSize];

while (true) {
int read = 0;
if (fis != null) {
read = fis.read(buf);
}

if (read == -1) {
break;
}
ps.write(buf, 0, read);
}
ps.flush();
// 注意关闭socket链接哦，不然客户端会等待server的数据过来，
// 直到socket超时，导致数据不完整。
fis.close();
s.close();
System.out.println("文件传输完成");
}

} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String arg[]) {
new Server().start();
}
}

显示错误为:
java.net.BindException: Address already in use: JVM_Bind
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.PlainSocketImpl.bind(Unknown Source)
at java.net.ServerSocket.bind(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at socket.FTP.Server.start(Server.java:20)
at socket.FTP.Server.main(Server.java:74)

...全文