这是偶第一次写java程序实现公司要求的FTP数据同步，所有原代码如下，以供各位参考并提出宝贵意见！另外俺还有两个功能没有实现，有请高手指点一二：1、如何删除FTP服务器上已经下载过的文件？2、如何将上传的文件改名？上传时在文件名前加“temp_”，上传完毕后需要把文件名改回来。3、如何使用openPassiveDataConnection()方法将ftp连接更改为主动连接，因为要从unix系统配置的ftp服务器下载文件的话，就需要主动连接。



/*
*******************************************************************************************************

Filename: ftp.java
Author:   leetsing(elove)
Create date: 2004-08-30
Use:   connect to FTP server,then upload and download file
Modify date: 2004-09-05 add to upload file
  2004-09-13 add to download file
Copy right: Magisky Media Technology Co.,Ltd.

*******************************************************************************************************
*/
//import cz.dhl.io.*;
//import cz.dhl.ftp.*;
import sun.net.ftp.*;
import sun.net.*;
import java.applet.*;
import java.io.*;
import java.io.IOException;
import java.util.StringTokenizer;
import sun.net.ftp.FtpClient;
import java.util.ArrayList;

public class ftp extends Applet
{
FtpClient aftp;
DataOutputStream outputs ;
TelnetInputStream ins;
TelnetOutputStream outs;

int ch;
public String a;
String hostname=\"\";
private String path = \"/\";

public static void main(String[] args)
{
String hostname = \"192.168.0.56\";
int port = 2121;
String uid = \"lee\";
String pwd = \"lee\";
String RWFileDir = \"D:\\\\smsftp\\\\\";//文件目录

//连接ftp服务器
ftp ft = new ftp();
ft.connect(RWFileDir,hostname,port,uid,pwd);

//下载文件
if (ft.aftp != null){
  try {
  ft.getNameList(RWFileDir);
  }catch(IOException e)
  {
  System.out.println(\"下载文件出错：\"+e);
  }
}


//上传文件
if (ft.aftp != null){
  String sdir = RWFileDir + \"subunsubfromsp\\\\\";
  File fdir = new File(sdir);
  String FileName = \"\";

  for(int i=0;i   FileName = sdir + (fdir.list());
 
  ft.uploadFile(RWFileDir,FileName);
  }
  //System.out.println(\"成功上传的文件：\");
  //ft.showFileContents(\"subunsubfromsp\\\\\");
}

//删除subunsubfromsp目录下已经上传的文件文件
// ft.deleFile(RWFileDir);

//断开服务器连接
ft.stop(RWFileDir);

}

public FtpClient connect(String RWFileDir,String hostname,int port,String uid,String pwd)
{
this.hostname = hostname;
System.out.println(\"正在连接\"+hostname+\"，请等待.....\");
try{
  aftp = new FtpClient(hostname,port);
  aftp.login(uid,pwd);
  aftp.binary();
  //aftp.openPortDataConnection();
  a = \"连接主机:\"+hostname+\"成功!\";
  System.out.println(a);
}
catch(FtpLoginException e){
  a=\"登陆主机:\"+hostname+\"失败!请检查用户名或密码是否正确：\"+e;
  System.out.println(a);
  //return false;
}
catch (IOException e){
  a=\"连接主机:\"+hostname+\"失败!请检查端口是否正确：\"+e;
  System.out.println(a);
  //return false;
}
catch(SecurityException e)
{
  a=\"无权限与主机:\"+hostname+\"连接!请检查是否有访问权限：\"+e;
  System.out.println(a);
  //return false;
}

log(RWFileDir,a);
return aftp;
}

public void stop(String RWFileDir)
{
String message = \"\";
try {
  if(aftp!=null){
  aftp.closeServer();
  message = \"与主机\"+hostname+\"连接已断开!\";
  System.out.println(message);
  log(RWFileDir,message);
  }
}
catch(IOException e)
{
  message = \"与主机\"+hostname+\"断开连接失败!\"+e;
  System.out.println(message);
  log(RWFileDir,message);
}
}


public boolean downloadFile(String RWFileDir,String filepathname){
boolean result=true;
String message = \"\";
if (aftp != null)
{
  System.out.println(\"正在下载文件\"+filepathname+\",请等待....\");
  String badfile = filepathname.substring(filepathname.length()-4,filepathname.length());
  String badlog = filepathname.substring(filepathname.length()-7,filepathname.length());
  String baddir = \"\";
  if ((badfile.compareTo(\".bad\") != 0) && (badlog.compareTo(\".badlog\") != 0)){
  baddir = \"subunsubtosp\\\\\";
  }
  else{
  baddir = \"bad\\\\\";
  }
  String strdir = \"subunsubtosp\\\\\";
  //System.out.println(RWFileDir + baddir + filepathname);
  try{
  //FtpClient fc=new FtpClient(\"192.168.0.56\",2121);
  //fc.login(\"lee\",\"lee\");
  int ch;
  File fi = new File(RWFileDir + baddir + filepathname);
  //aftp.cd(strdir);
  RandomAccessFile getFile = new RandomAccessFile(fi,\"rw\");
  getFile.seek(0);
  TelnetInputStream fget=aftp.get(strdir+filepathname);
  DataInputStream puts = new DataInputStream(fget);
  while ((ch = puts.read()) >= 0) {
  getFile.write(ch);
 
  }
  //s.delete();
 
  fget.close();
  getFile.close();
  //fc.closeServer();

  message = \"下载\"+filepathname+\"文件到\"+baddir +\"目录成功!\";
  System.out.println(message);
  log(RWFileDir,message);
  }
  catch(IOException e){
  message = \"下载\"+filepathname+\"文件到\"+baddir +\"目录失败!\"+e;
  System.out.println(message);
  log(RWFileDir,message);
  result = false ;

  }
}
else{
  result = false;
}
return result;
}


public boolean uploadFile(String RWFileDir,String filepathname){
boolean result=true;
String message = \"\";
if (aftp != null)
{
  System.out.println(\"正在上传文件\"+filepathname+\",请等待....\");

  try{
  String fg =new String(\"\\\\subunsubfromsp\\\\\");
  int index = filepathname.lastIndexOf(fg);
  String filename = filepathname.substring(index+1);
  File localFile = new File(filepathname) ;
   
  RandomAccessFile sendFile = new RandomAccessFile(filepathname,\"r\");
  //
  sendFile.seek(0);
  //改名上传temp_
  filename = filename.substring(0,15)+\"temp_\"+filename.substring(15,filename.length());
  outs = aftp.put(filename);
  outputs = new DataOutputStream(outs);
  while (sendFile.getFilePointer() < sendFile.length() )
  {
  ch = sendFile.read();
  outputs.write(ch);
  }
 
  rename(filename.substring(15,filename.length()),filename.substring(20,filename.length()));
  outs.close();
  sendFile.close();
 
  message = \"上传\"+filepathname+\"文件成功!\";
  System.out.println(message);
  log(RWFileDir,message);
  }
  catch(IOException e){
  message = \"上传\"+filepathname+\"文件失败!\"+e;
  System.out.println(message);
  log(RWFileDir,message);
  result = false ;

  }
}
else{
  result = false;
}
return result;
}

public void rename(String oldName,String newName){

  //aftp.renameTo(oldName,newName);
  File Old = new File(oldName); //oldName
  File New = new File(newName); //newName
  //aftp.renameTo(New);
  //boolean Old.renameTo(File newName);
  //System.out.println(Old);
  //System.out.println(New);

}

public static void deleFile(String RWFileDir) {
//try {
//取得ReadFile目录下的txt文件
String sdir = RWFileDir + \"subunsubfromsp\\\\\";
File fdir = new File(sdir);
String FileName = \"\";
int j = fdir.list().length;

System.out.println(sdir+\"目录下要删除的文件数：\"+fdir.list().length);
File file;
for(int i=0;i {
  //删除subunsubfromsp中的txt文件
  FileName = RWFileDir + \"subunsubfromsp\\\\\" + (fdir.list())[0];
  file = new File(FileName);
  file.delete();
  System.out.println(\"已经成功删除\"+FileName+\"文件！\");
}
//}
//catch (IOException e) {
// System.out.println(\"删除txt文件错误!\");
// e.printStackTrace();
//}
}


public void showFileContents(String strdir)
{
StringBuffer buf = new StringBuffer();
try {
  aftp.cd(strdir);
  ins= aftp.list();
  while ((ch=ins.read())>=0){
  buf.append((char)ch);
  }
 
  System.out.println(buf.toString());

  ins.close();
    }
catch(IOException e)
{
}
}



// 返回当前目录的所有文件及文件夹

public ArrayList getFileList() throws IOException {
BufferedReader dr = new BufferedReader(new InputStreamReader(aftp.list()));
ArrayList al = new ArrayList();
String s = \"\";
while ( (s = dr.readLine()) != null) {
al.add(s);
}
return al;
}

public void setPath(String path) throws IOException {
if (aftp == null)
this.path = path;
else {
  aftp.cd(path);
}
}

// 返回当前目录的文件名称

public ArrayList getNameList(String RWFileDir) throws IOException {

BufferedReader dr = new BufferedReader(new InputStreamReader(aftp.nameList(\"subunsubtosp\\\\\")));
ArrayList al = new ArrayList();
String s = \"\";
while ( (s = dr.readLine()) != null) {
  al.add(s);
  s = s.substring(13,s.length());
  isFile(s);
  downloadFile(RWFileDir,s);
  //String strFileDelF = aftp.nameList(\"subunsubtosp\\\\\");
  File fileDelF=new File(s);
  fileDelF.delete();
}
return al;
//System.out.println(al.add(s));
}

// 判断一行文件信息是否为目录

public boolean isDir(String line) {
return ( (String) parseLine(line).get(0)).indexOf(\"d\") != -1;
}

public boolean isFile(String line) {
return!isDir(line);
}

// 处理getFileList取得的行信息

private ArrayList parseLine(String line) {
ArrayList s1 = new ArrayList();
StringTokenizer st = new StringTokenizer(line, \" \");
while (st.hasMoreTokens()) {
  s1.add(st.nextToken());
}
  return s1;
}

//写消息日志
public static void log(String RWFileDir,String msg)
{
String message = \"\";
try {
  java.text.DateFormat df = new java.text.SimpleDateFormat(\"yyyy-MM-dd HH:mm:ss\");
  java.text.DateFormat dflog = new java.text.SimpleDateFormat(\"yyyyMMdd\");
  java.util.Date date = new java.util.Date() ;
  String datestr = df.format(new java.util.Date()) ;
  String datelog = dflog.format(new java.util.Date()) ;
  //String datelog = datestr.substring(0,10);
  //datelog = datelog.replace(\'-\',\' \');

  //按日期每天生成一个日志文件
  FileWriter fwl = new FileWriter(RWFileDir + \"CMSSftp\"+datelog+\".log\",true);
  PrintWriter outl = new PrintWriter(fwl);
  outl.println(datestr + \" \" + msg);
  outl.close();
  fwl.close();
}catch (IOException e) {
  message = \"写log文件错误!\"+e;
  e.printStackTrace();
  log(RWFileDir,message);
  System.out.println(message);
}
}
}
转自：http://bbs.java.ccidnet.com/read.php?tid=135053&fpage=4