利用apache ftp工具实现文件的上传下载和删除，具体如下

1、下载相应的jar包

     commons-net-1.4.1.jar

2、实现代码如下：

public class FtpUtils { 
    //ftp服务器地址 
    public String hostname = "192.168.1.249"; 
    //ftp服务器端口号默认为21 
    public Integer port = 21 ; 
    //ftp登录账号 
    public String username = "root"; 
    //ftp登录密码 
    public String password = "123"; 
     
    public FTPClient ftpClient = null; 
     
    /** 
     * 初始化ftp服务器 
     */ 
    public void initFtpClient() { 
      ftpClient = new FTPClient(); 
      ftpClient.setControlEncoding("utf-8"); 
      try { 
        System.out.println("connecting...ftp服务器:"+this.hostname+":"+this.port);  
        ftpClient.connect(hostname, port); //连接ftp服务器 
        ftpClient.login(username, password); //登录ftp服务器 
        int replyCode = ftpClient.getReplyCode(); //是否成功登录服务器 
        if(!FTPReply.isPositiveCompletion(replyCode)){ 
          System.out.println("connect failed...ftp服务器:"+this.hostname+":"+this.port);  
        } 
        System.out.println("connect successfu...ftp服务器:"+this.hostname+":"+this.port);  
      }catch (MalformedURLException e) {  
        e.printStackTrace();  
      }catch (IOException e) {  
        e.printStackTrace();  
      }  
    } 
 
    /** 
    * 上传文件 
    * @param pathname ftp服务保存地址 
    * @param fileName 上传到ftp的文件名 
    * @param originfilename 待上传文件的名称（绝对地址） * 
    * @return 
    */ 
    public boolean uploadFile( String pathname, String fileName,String originfilename){ 
      boolean flag = false; 
      InputStream inputStream = null; 
      try{ 
        System.out.println("开始上传文件"); 
        inputStream = new FileInputStream(new File(originfilename)); 
        initFtpClient(); 
        ftpClient.setFileType(ftpClient.BINARY_FILE_TYPE); 
        CreateDirecroty(pathname); 
        ftpClient.makeDirectory(pathname); 
        ftpClient.changeWorkingDirectory(pathname); 
        ftpClient.storeFile(fileName, inputStream); 
        inputStream.close(); 
        ftpClient.logout(); 
        flag = true; 
        System.out.println("上传文件成功"); 
      }catch (Exception e) { 
        System.out.println("上传文件失败"); 
        e.printStackTrace(); 
      }finally{ 
        if(ftpClient.isConnected()){  
          try{ 
            ftpClient.disconnect(); 
          }catch(IOException e){ 
            e.printStackTrace(); 
          } 
        }  
        if(null != inputStream){ 
          try { 
            inputStream.close(); 
          } catch (IOException e) { 
            e.printStackTrace(); 
          }  
        }  
      } 
      return true; 
    } 
    /** 
     * 上传文件 
     * @param pathname ftp服务保存地址 
     * @param fileName 上传到ftp的文件名 
     * @param inputStream 输入文件流 
     * @return 
     */ 
    public boolean uploadFile( String pathname, String fileName,InputStream inputStream){ 
      boolean flag = false; 
      try{ 
        System.out.println("开始上传文件"); 
        initFtpClient(); 
        ftpClient.setFileType(ftpClient.BINARY_FILE_TYPE); 
        CreateDirecroty(pathname); 
        ftpClient.makeDirectory(pathname); 
        ftpClient.changeWorkingDirectory(pathname); 
        ftpClient.storeFile(fileName, inputStream); 
        inputStream.close(); 
        ftpClient.logout(); 
        flag = true; 
        System.out.println("上传文件成功"); 
      }catch (Exception e) { 
        System.out.println("上传文件失败"); 
        e.printStackTrace(); 
      }finally{ 
        if(ftpClient.isConnected()){  
          try{ 
            ftpClient.disconnect(); 
          }catch(IOException e){ 
            e.printStackTrace(); 
          } 
        }  
        if(null != inputStream){ 
          try { 
            inputStream.close(); 
          } catch (IOException e) { 
            e.printStackTrace(); 
          }  
        }  
      } 
      return true; 
    } 
    //改变目录路径 
     public boolean changeWorkingDirectory(String directory) { 
        boolean flag = true; 
        try { 
          flag = ftpClient.changeWorkingDirectory(directory); 
          if (flag) { 
           System.out.println("进入文件夹" + directory + " 成功！"); 
 
          } else { 
            System.out.println("进入文件夹" + directory + " 失败！开始创建文件夹"); 
          } 
        } catch (IOException ioe) { 
          ioe.printStackTrace(); 
        } 
        return flag; 
      } 
 
    //创建多层目录文件，如果有ftp服务器已存在该文件，则不创建，如果无，则创建 
    public boolean CreateDirecroty(String remote) throws IOException { 
      boolean success = true; 
      String directory = remote + "/"; 
      // 如果远程目录不存在，则递归创建远程服务器目录 
      if (!directory.equalsIgnoreCase("/") && !changeWorkingDirectory(new String(directory))) { 
        int start = 0; 
        int end = 0; 
        if (directory.startsWith("/")) { 
          start = 1; 
        } else { 
          start = 0; 
        } 
        end = directory.indexOf("/", start); 
        String path = ""; 
        String paths = ""; 
        while (true) { 
          String subDirectory = new String(remote.substring(start, end).getBytes("GBK"), "iso-8859-1"); 
          path = path + "/" + subDirectory; 
          if (!existFile(path)) { 
            if (makeDirectory(subDirectory)) { 
              changeWorkingDirectory(subDirectory); 
            } else { 
              System.out.println("创建目录[" + subDirectory + "]失败"); 
              changeWorkingDirectory(subDirectory); 
            } 
          } else { 
            changeWorkingDirectory(subDirectory); 
          } 
 
          paths = paths + "/" + subDirectory; 
          start = end + 1; 
          end = directory.indexOf("/", start); 
          // 检查所有目录是否创建完毕 
          if (end <= start) { 
            break; 
          } 
        } 
      } 
      return success; 
    } 
 
   //判断ftp服务器文件是否存在   
    public boolean existFile(String path) throws IOException { 
        boolean flag = false; 
        FTPFile[] ftpFileArr = ftpClient.listFiles(path); 
        if (ftpFileArr.length > 0) { 
          flag = true; 
        } 
        return flag; 
      } 
    //创建目录 
    public boolean makeDirectory(String dir) { 
      boolean flag = true; 
      try { 
        flag = ftpClient.makeDirectory(dir); 
        if (flag) { 
          System.out.println("创建文件夹" + dir + " 成功！"); 
 
        } else { 
          System.out.println("创建文件夹" + dir + " 失败！"); 
        } 
      } catch (Exception e) { 
        e.printStackTrace(); 
      } 
      return flag; 
    } 
     
    /** * 下载文件 * 
    * @param pathname FTP服务器文件目录 * 
    * @param filename 文件名称 * 
    * @param localpath 下载后的文件路径 * 
    * @return */ 
    public boolean downloadFile(String pathname, String filename, String localpath){  
      boolean flag = false;  
      OutputStream os=null; 
      try {  
        System.out.println("开始下载文件"); 
        initFtpClient(); 
        //切换FTP目录  
        ftpClient.changeWorkingDirectory(pathname);  
        FTPFile[] ftpFiles = ftpClient.listFiles();  
        for(FTPFile file : ftpFiles){  
          if(filename.equalsIgnoreCase(file.getName())){  
            File localFile = new File(localpath + "/" + file.getName());  
            os = new FileOutputStream(localFile);  
            ftpClient.retrieveFile(file.getName(), os);  
            os.close();  
          }  
        }  
        ftpClient.logout();  
        flag = true;  
        System.out.println("下载文件成功"); 
      } catch (Exception e) {  
        System.out.println("下载文件失败"); 
        e.printStackTrace();  
      } finally{  
        if(ftpClient.isConnected()){  
          try{ 
            ftpClient.disconnect(); 
          }catch(IOException e){ 
            e.printStackTrace(); 
          } 
        }  
        if(null != os){ 
          try { 
            os.close(); 
          } catch (IOException e) { 
            e.printStackTrace(); 
          }  
        }  
      }  
      return flag;  
    } 
     
    /** * 删除文件 * 
    * @param pathname FTP服务器保存目录 * 
    * @param filename 要删除的文件名称 * 
    * @return */  
    public boolean deleteFile(String pathname, String filename){  
      boolean flag = false;  
      try {  
        System.out.println("开始删除文件"); 
        initFtpClient(); 
        //切换FTP目录  
        ftpClient.changeWorkingDirectory(pathname);  
        ftpClient.dele(filename);  
        ftpClient.logout(); 
        flag = true;  
        System.out.println("删除文件成功"); 
      } catch (Exception e) {  
        System.out.println("删除文件失败"); 
        e.printStackTrace();  
      } finally { 
        if(ftpClient.isConnected()){  
          try{ 
            ftpClient.disconnect(); 
          }catch(IOException e){ 
            e.printStackTrace(); 
          } 
        }  
      } 
      return flag;  
    } 
     
    public static void main(String[] args) { 
      FtpUtils ftp =new FtpUtils();  
      //ftp.uploadFile("ftpFile/data", "123.docx", "E://123.docx"); 
      //ftp.downloadFile("ftpFile/data", "123.docx", "F://"); 
      ftp.deleteFile("ftpFile/data", "123.docx"); 
      System.out.println("ok"); 
    } 
}