Java从FTP服务器上传下载文件的代码

import java.io.*;  import java.util.*;  import java.sql.*;  import java.net.Socket;  import java.net.ServerSocket;  import java.net.InetAddress;  import sun.net.ftp.*;  import sun.net.TelnetInputStream;  import sun.net.TelnetOutputStream;    /*  * 用于连接到FTP服务器上  * @return String 若失败则返回失败信息，成功返回空字符串  */  private String connectToFtpServer(){  if ((this.ftpserver==null)||(this.ftpserver.equals(""))) return "FTP服务器名设置不正确!";    try{  fc.openServer(this.ftpserver);  fc.login(this.ftpuser,this.ftppwd);  fc.ascii();  }catch(FtpLoginException e){  return "没有与FTP服务器连接的权限,或用户名密码设置不正确!";  }catch(IOException e){  return "与FTP服务器连接失败!";  }catch(SecurityException e){  return "没有权限与FTP服务器连接";  }  return "";  }  /*  * 用于关闭与FTP服务器的连接  */  private void closeFtpConnect(){  if (fc.serverIsOpen()){  try{  fc.closeServer();  }catch(Exception e){  }finally{  fc = null;  }  }  }  public String downloadFile(String fileName){  //只下载文本文件或XML文件  if (!this.isTextFile(fileName)) return fileName + "不是XML文件或文本文件";  String retMessage = "";    if (!fc.serverIsOpen()){  retMessage = this.connectToFtpServer();  if (!retMessage.equals("")) return "下载文件：" + fileName + "时无法和FTP服务器连接";  }    //if (conn == null) return "下载文件：" + fileName + "时无法连接到数据库";    String chkSql = "select 1 from t_trans_log where file_name = '" + fileName + "'";  if (sqlbean.checkQueryRowCount(chkSql) > 0) return retMessage;    if (this.dldir==null) this.dldir = "";    try{      TelnetInputStream is = fc.get(this.dldir + "/" + fileName);  BufferedReader br = new BufferedReader(new InputStreamReader(is));    //读取文件内容到stringbuffer  StringBuffer sb = new StringBuffer();  int length;    char buffer[] = new char[1];  while((length = br.read(buffer,0,1)) != -1) sb.append(buffer);    //构造sql语句插入记录  //String ls_lsh = get_lsh(12);  String ls_lsh = ah.getAutoID("xf_lsh",12);    String ls_sql = "insert into t_trans_log(tran_id,tran_flag,file_name,file_content)values('"  ls_sql += ls_lsh + "','0','" + fileName + "','" + sb.toString() + "')";    conn = connmanager.getConnection();  conn.setAutoCommit(false);    sqlbean.executeUpdate(conn,ls_sql);      //将stringbuffer写入文件中  byte buf[] = sb.toString().getBytes();    OutputStream f1 = new FileOutputStream(this.bdldir + "/" + fileName);  f1.write(buf);  f1.close();    is.close();  br.close();    //删除文件  this.deleteFile(this.dldir + "/" + fileName);    conn.commit();  conn.setAutoCommit(true);  connmanager.close(conn);  }catch(SQLException e){  retMessage = "下载文件：" + fileName + "时发生数据库错误：" + e.getMessage();  }catch(IOException e){  retMessage = "下载文件：" + fileName + "时发生文件读写错误：" + e.getMessage();  }  return retMessage;  }      //下载指定目录下的所有文件  public String downloadFiles(String dirName){  String retMessage = "";    if ((dirName == null)||(dirName.equals(""))) dirName = this.dldir;  String[] sa = this.list();  for (int i = 0;i < sa.length;i++){  retMessage = this.downloadFile(sa[i]);  if (!retMessage.equals("")) return retMessage;  }    return retMessage;  }    //下载FTP服务器上的所有文件  public String downloadFiles(){  return downloadFiles(this.dldir);  }        public String uploadFile(String fileName){  String retMessage = "";    if (!fc.serverIsOpen()){  retMessage = this.connectToFtpServer();  if (!retMessage.equals("")) return "上传文件：" + fileName + "时无法和FTP服务器连接";  }  //if (conn == null) return "上传文件：" + fileName + "时无法连接到数据库";    //String chkSql = "select 1 from t_trans_log where file_name = '" + fileName + "'";  //if (Utils.checkQueryRowCount(conn,chkSql) > 0) return retMessage;    try{  if (this.uldir==null) this.uldir = "";  if (this.buldir==null) this.buldir = "";    TelnetOutputStream os = fc.put(this.uldir + "/" + fileName);  BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(os));    StringBuffer sb = new StringBuffer();  InputStream f1 = new FileInputStream(this.buldir + "/" + fileName);  int size = f1.available();  byte b[] = new byte[size];  while(f1.read(b)!= -1) sb.append(new String(b,0,b.length));    //构造sql语句插入记录  //String ls_sql = "insert into t_trans_log(tran_id,file_name,file_content)values('" + get_lsh(12) + "','" + fileName + "','" + sb.toString() + "')";  String ls_sql = "insert into t_trans_log(tran_id,file_name,file_content)values('" + ah.getAutoID("xf_lsh",12) + "','" + fileName + "','" + sb.toString() + "')";  conn = connmanager.getConnection();  conn.setAutoCommit(false);    sqlbean.executeUpdate(conn,ls_sql);    //写入文件  wr.write(sb.toString());    f1.close();  wr.close();  os.close();    //删除本地文件    File ls_file = new File(this.buldir + "/" + fileName);    ls_file.delete();    conn.commit();  conn.setAutoCommit(true);  connmanager.close(conn);  }catch(SQLException e){  retMessage = "上传文件：" + fileName + "时发生数据库错误：" + e.getMessage();  }catch(IOException e){  retMessage = "上传文件：" + fileName + "时发生文件读写错误：" + e.getMessage();  }    return retMessage;  }    /**  * 功能：获取指定目录文件列表并上传每一个文件  */  public String uploadFiles(){  String retMessage = "";    if (this.buldir == null) this.buldir = "";    File ls_file = new File(this.buldir);  File[] entries = ls_file.listFiles();    for(int i=0; i this.uploadFile(entries[i].getName());  if (!retMessage.equals("")) return retMessage;  }  return retMessage;  }    public String deleteFile(String fileName){  String retMessage = "";  try{  Socket socket = new Socket(this.ftpserver,this.ftpport);  BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));  if (!reader.readLine().startsWith("220")) return "DELE 无法连接到指定的FTP服务器";  Writer writer = new OutputStreamWriter(socket.getOutputStream());  writer.write("USER " + this.ftpuser + "rn");  writer.flush();  if (!reader.readLine().startsWith("331")) return "DELE 指定的登录FTP用户名无效";  writer.write("PASS " + this.ftppwd + "rn");  writer.flush();  if (!reader.readLine().startsWith("230")) return "DELE FTP用户的登录口令错误";  writer.write("DELE " + fileName + "rn");  writer.flush();  if (!reader.readLine().startsWith("250")) return "无法删除指定文件" + fileName;  writer.close();  reader.close();  socket.close();  }catch(Exception e){  retMessage = "删除文件" + fileName + "时发生错误" + e.getMessage();  }  return retMessage;  }    /**  * 功能：获取指定目录下以分号分隔的文件名列表  */  public String getDownloadFileList(String dirName){  StringBuffer sb = new StringBuffer();  String[] sa = list(dirName);  int saLength = sa.length;    for (int i = 0; i < saLength; i++) sb.append(sa[i]).append(";");    return sb.toString();  }    /**  * 功能：获取默认下载目录下以分号分隔的文件名列表  */  public String getDownloadFileList(){  return getDownloadFileList(this.dldir);  }    /**  * 功能：以数组的形式返回服务器上指定目录下的文件名列表  */  public String[] list(String dirName){  String[] fileNameList = new String[0];  Vector lines = new Vector();  String line = null;    if (fc.serverIsOpen()){  try{  fc.cd(dirName.equals("")?this.dldir:dirName);  TelnetInputStream ins = fc.list();  fc.cd("/");    LineNumberReader in = new LineNumberReader(new InputStreamReader(ins));  line = in.readLine();  while((line != null)&&!(line.trim().equals(""))&&!(line.trim().equals("/n"))){  lines.add(line.substring(line.lastIndexOf(" ") + 1,line.length()));  line = in.readLine();  }    in.close();  ins.close();  }catch(Exception e){  }    if (!lines.isEmpty()) fileNameList = (String[])lines.toArray(fileNameList);  }    return fileNameList;  }    /**  * 功能：以数组的形式返回服务器上默认下载目录下的文件名列表  */  public String[] list(){  return this.list(this.dldir);  }    public String getDlDir(){return this.dldir;}    /**  * 功能：用于判断文件是否是XML或TXT文件  */  private boolean isTextFile(String fileName){  return (fileName.toLowerCase().endsWith(".xml")||fileName.toLowerCase().endsWith(".txt"));  }  }