【参加讨论】面我们要处理用户连接,也就是FtpConnection类。Ftp连接本质上是一个状态机,当FtpConnection接收到用户命令后,根据当前状态决定响应及下一个状态。不过我们不需要考虑实现一个复杂的状态机,只须监听/接收/处理/响应即可:
package jftp;
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.*;
public class FtpConnection extends Thread {
/** 主目录 */
static public String root = null;
private String currentDir = "/"; // 当前目录
private Socket socket;
private BufferedReader reader = null;
private BufferedWriter writer = null;
private String clientIP = null;
private Socket tempSocket = null; // tempSocket用于传送文件
private ServerSocket pasvSocket = null; // 用于被动模式
private String host = null;
private int port = (-1);
public FtpConnection(Socket socket) {
this.socket = socket;
this.clientIP = socket.getInetAddress().getHostAddress();
}
public void run() {
String command;
try {
System.out.println(clientIP + " connected.");
socket.setSoTimeout(60000); // ftp超时设定
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
response("220-欢迎消息......");
response("220-欢迎消息......");
response("220 注意最后一行欢迎消息没有“-”");
for(;;) {
command = reader.readLine();
if(command == null)
break;
System.out.println("command from " + clientIP + " : " + command);
parseCommand(command);
if(command.equals("QUIT")) // 收到QUIT命令
break;
}
}
catch(Exception e) { e.printStackTrace(); }
finally {