140个java经典示例

import java.net.*; import java.io.*; import java.util.*; class FtpClient { static final boolean debug = false; public static final int FTP_PORT = 21; static int FTP_SUCCESS = 1; static int FTP_TRY_AGAIN = 2; static int FTP_ERROR = 3; /** socket for data transfer */ private Socket dataSocket = null; private boolean replyPending = false; private boolean binaryMode = false; private boolean passiveMode = false; /** user name for login */ String user = null; /** password for login */ String password = null; /** last command issued */ String command; /** The last reply code from the ftp daemon. */ int lastReplyCode; /** Welcome message from the server, if any. */ public String welcomeMsg; /** Array of strings (usually 1 entry) for the last reply from the server. */ protected Vector serverResponse = new Vector(1); /** Socket for communicating with server. */ protected Socket serverSocket = null; /** Stream for printing to the server. */ public PrintWriter serverOutput; /** Buffered stream for reading replies from server. */ public InputStream serverInput; /** Return server connection status */ public boolean serverIsOpen() { return serverSocket != null; } /**Set Passive mode Trasfers*/ public void setPassive(boolean mode) { passiveMode = mode; } public int readServerResponse() throws IOException { StringBuffer replyBuf = new StringBuffer(32); int c; int continuingCode = -1; int code = -1; String response; if (debug) System.out.println("readServerResponse start"); try{ while (true) { //if (debug) System.out.println("readServerResponse outer while loop: "+ serverInput.available()); while ((c = serverInput.read()) != -1) { if (c == '\r') { if ((c = serverInput.read()) != '\n') replyBuf.append('\r'); } replyBuf.append((char)c); if (c == '\n') break; } if (debug) System.out.println("Now past inner while loop"); response = replyBuf.toString(); replyBuf.setLength(0); if (debug) { System.out.print(response); } try { code = Integer.parseInt(response.substring(0, 3)); } catch (NumberFormatException e) { code = -1; } catch (StringIndexOutOfBoundsException e) { /* this line doesn't contain a response code, so we just completely ignore it */ continue; } serverResponse.addElement(response); if (continuingCode != -1) { /* we've seen a XXX- sequence */ if (code != continuingCode || (response.length() >= 4 && response.charAt(3) == '-')) { continue; } else { /* seen the end of code sequence */ continuingCode = -1; break; } } else if (response.length() >= 4 && response.charAt(3) == '-') { continuingCode = code; continue; } else { break; } } }catch(Exception e){e.printStackTrace();} if (debug) System.out.println("readServerResponse done"); return lastReplyCode = code; } /** Sends command <i>cmd</i> to the server. */ public void sendServer(String cmd) { if (debug) System.out.println("sendServer start"); serverOutput.println(cmd); if (debug) System.out.println("sendServer done"); } /** Returns all server response strings. */ public String getResponseString() { String s = new String(); for(int i = 0;i < serverResponse.size();i++) { s+=serverResponse.elementAt(i); } serverResponse = new Vector(1); return s; } public String getResponseStringNoReset() { String s = new String(); for(int i = 0;i < serverResponse.size();i++) { s+=serverResponse.elementAt(i); } return s; } /** * issue the QUIT command to the FTP server and close the connection. */ public void closeServer() throws IOException { if (serverIsOpen()) { issueCommand("QUIT"); if (! serverIsOpen()) { return; } serverSocket.close(); serverSocket = null; serverInput = null; serverOutput = null; } } protected int issueCommand(String cmd) throws IOException { command = cmd; int reply; if (debug) System.out.println(cmd); if (replyPending) { if (debug) System.out.println("replyPending"); if (readReply() == FTP_ERROR) System.out.print("Error reading pending reply\n"); } replyPending = false; do { sendServer(cmd); reply = readReply(); //if (debug) System.out.println("in while loop of issueCommand method"); } while (reply == FTP_TRY_AGAIN); return reply; } protected void issueCommandCheck(String cmd) throws IOException { if (debug) System.out.println("issueCommandCheck"); if (issueCommand(cmd) != FTP_SUCCESS) { throw new FtpProtocolException(cmd); } } protected int readReply() throws IOException { lastReplyCode = readServerResponse(); switch (lastReplyCode / 100) { case 1: replyPending = true; /* falls into ... */ case 2://This case is for future purposes. If not properly used, it might cause an infinite loop. //Don't add any code here , unless you know what you are doing. case 3: return FTP_SUCCESS; case 5: if (lastReplyCode == 530) { if (user == null) { throw new FtpLoginException("Not logged in"); } return FTP_ERROR; } if (lastReplyCode == 550) { if (!command.startsWith("PASS")) throw new FileNotFoundException(command); else throw new FtpLoginException("Error: Wrong Password!"); } } /* this statement is not reached */ return FTP_ERROR; } protected Socket openDataConnection(String cmd) throws IOException { ServerSocket portSocket = null; String portCmd; InetAddress myAddress = InetAddress.getLocalHost(); byte addr[] = myAddress.getAddress(); int shift; String ipaddress; int port = 0; IOException e; if (this.passiveMode) { /* First let's attempt to initiate Passive transfers */ try { // PASV code getResponseString(); if (issueCommand("PASV") == FTP_ERROR) { e = new FtpProtocolException("PASV"); throw e; } String reply = getResponseStringNoReset(); reply = reply.substring(reply.lastIndexOf("(")+1,reply.lastIndexOf(")")); StringTokenizer st = new StringTokenizer(reply, ","); S