java基于Apache FTP点断续传的文件上传和下载

基于Apache FTP实现文件上传下载工具 ,上传文件时需要考虑以下问题(实例是续传功能):

(1)、 FTP服务器是否存在改目录,如果不存在目录则需要创建目录。

(2)、判断上传文件是否已经存在,如果存在是需要删除后再上传还是续传。

1、上传或下载状态的枚举类:

package com.scengine.wtms.utils.ftp; 
 
public enum UploadStatus 
{ 
  File_Exits(0), Create_Directory_Success(1), Create_Directory_Fail(2), Upload_From_Break_Success(3), Upload_From_Break_Faild(4), Download_From_Break_Success(5), Download_From_Break_Faild(6), Upload_New_File_Success(7), Upload_New_File_Failed(8), Delete_Remote_Success(9), Delete_Remote_Faild(10),Remote_Bigger_Local(11),Remote_smaller_locall(12); 
 
  private int status; 
 
  public int getStatus() 
  { 
    return status; 
  } 
 
  public void setStatus(int status) 
  { 
    this.status = status; 
  } 
 
  UploadStatus(int status) 
  { 
    this.status = status; 
  } 
} 

2、工具类代码:

package com.scengine.wtms.utils.ftp; 
 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.io.PrintWriter; 
import org.apache.commons.net.PrintCommandListener; 
import org.apache.commons.net.ftp.FTP; 
import org.apache.commons.net.ftp.FTPClient; 
import org.apache.commons.net.ftp.FTPFile; 
import org.apache.commons.net.ftp.FTPReply; 
 
public class ContinueFTP 
{ 
 
  private FTPClient ftpClient = new FTPClient(); 
 
  /** 
   * 对象构造 设置将过程中使用到的命令输出到控制台 
   */ 
  public ContinueFTP() 
  { 
    this.ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out))); 
  } 
 
  /** 
   * 
   * java编程中用于连接到FTP服务器 
   * 
   * @param hostname 
   *      主机名 
   * 
   * @param port 
   *      端口 
   * 
   * @param username 
   *      用户名 
   * 
   * @param password 
   *      密码 
   * 
   * @return 是否连接成功 
   * 
   * @throws IOException 
   */ 
 
  public boolean connect(String hostname, int port, String username, String password) throws IOException 
  { 
 
    ftpClient.connect(hostname, port); 
 
    if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) 
    { 
 
      if (ftpClient.login(username, password)) 
      { 
        return true; 
      } 
    } 
    disconnect(); 
    return false; 
 
  } 
 
  /** 
   * 
   * 从FTP服务器上下载文件 
   * 
   * @param remote 
   *      远程文件路径 
   * 
   * @param local 
   *      本地文件路径 
   * 
   * @return 是否成功 
   * 
   * @throws IOException 
   */ 
 
  @SuppressWarnings("resource") 
  public boolean download(String remote, String local) throws IOException 
  { 
 
    ftpClient.enterLocalPassiveMode(); 
 
    ftpClient.setFileType(FTP.BINARY_FILE_TYPE); 
 
    boolean result; 
 
    File f = new File(local); 
 
    FTPFile[] files = ftpClient.listFiles(remote); 
 
    if (files.length != 1) 
    { 
      System.out.println("远程文件不唯一"); 
      return false; 
    } 
 
    long lRemoteSize = files[0].getSize(); 
 
    if (f.exists()) 
    { 
      OutputStream out = new FileOutputStream(f, true); 
      System.out.println("本地文件大小为:" + f.length()); 
 
      if (f.length() >= lRemoteSize) 
      { 
 
        System.out.println("本地文件大小大于远程文件大小,下载中止"); 
 
        return false; 
 
      } 
 
      ftpClient.setRestartOffset(f.length()); 
 
      result = ftpClient.retrieveFile(remote, out); 
 
      out.close(); 
 
    } else 
    { 
 
      OutputStream out = new FileOutputStream(f); 
      result = ftpClient.retrieveFile(remote, out); 
      out.close(); 
    } 
 
    return result; 
 
  } 
 
  /** 
   * 
   * 上传文件到FTP服务器,支持断点续传 
   * 
   * @param local 
   *      本地文件名称,绝对路径 
   * 
   * @param remote 
   *      远程文件路径,使用/home/directory1/subdirectory/file.ext 
   *      按照Linux上的路径指定方式,支持多级目录嵌套,支持递归创建不存在的目录结构 
   * 
   * @return 上传结果 
   * 
   * @throws IOException 
   */ 
 
  @SuppressWarnings("resource") 
  public UploadStatus upload(String local, String remote) throws IOException 
  { 
 
    // 设置PassiveMode传输 
 
    ftpClient.enterLocalPassiveMode(); 
 
    // 设置以二进制流的方式传输 
 
    ftpClient.setFileType(FTP.BINARY_FILE_TYPE); 
 
    UploadStatus result; 
 
    // 对远程目录的处理 
 
    String remoteFileName = remote; 
 
    if (remote.contains("/")) 
    { 
 
      remoteFileName = remote.substring(remote.lastIndexOf("/") + 1); 
 
      String directory = remote.substring(0, remote.lastIndexOf("/") + 1); 
 
      if (!directory.equalsIgnoreCase("/") && !ftpClient.changeWorkingDirectory(directory)) 
      { 
 
        // 如果远程目录不存在,则递归创建远程服务器目录 
 
        int start = 0; 
 
        int end = 0; 
 
        if (directory.startsWith("/")) 
        { 
 
          start = 1; 
 
        } else 
        { 
 
          start = 0; 
 
        } 
 
        end = directory.indexOf("/", start); 
 
        while (true) 
        { 
 
          String subDirectory = remote.substring(start, end); 
 
          if (!ftpClient.changeWorkingDirectory(subDirectory)) 
          { 
 
            if (ftpClient.makeDirectory(subDirectory)) 
            { 
 
              ftpClient.changeWorkingDirectory(subDirectory); 
 
            } else 
            { 
 
              System.out.println("创建目录失败"); 
 
              return UploadStatus.Create_Directory_Fail; 
 
            } 
 
          } 
 
          start = end + 1; 
 
          end = directory.indexOf("/", start); 
 
          // 检查所有目录是否创建完毕 
 
          if (end <= start) 
          { 
 
            break; 
 
          } 
 
        } 
 
      } 
 
    } 
 
    // 检查远程是否存在文件 
 
    FTPFile[] files = ftpClient.listFiles(remoteFileName); 
 
    if (files.length == 1) 
    { 
 
      long remoteSize = files[0].getSize(); 
 
      File f = new File(local); 
 
      long localSize = f.length(); 
 
      if (remoteSize == localSize) 
      { 
 
        return UploadStatus.File_Exits; 
 
      } else if (remoteSize > localSize) 
      { 
 
        return UploadStatus.Remote_Bigger_Local; 
 
      } 
 
      // 尝试移动文件内读取指针,实现断点续传 
 
      InputStream is = new FileInputStream(f); 
 
      if (is.skip(remoteSize) == remoteSize) 
      { 
 
        ftpClient.setRestartOffset(remoteSize); 
 
        if (ftpClient.storeFile(remote, is)) 
        { 
 
          return UploadStatus.Upload_From_Break_Success; 
 
        } 
 
      } 
 
      // 如果断点续传没有成功,则删除服务器上文件,重新上传 
 
      if (!ftpClient.deleteFile(remoteFileName)) 
      { 
 
        return UploadStatus.Delete_Remote_Faild; 
 
      } 
 
      is = new FileInputStream(f); 
 
      if (ftpClient.storeFile(remote, is)) 
      { 
 
        result = UploadStatus.Upload_New_File_Success; 
 
      } else 
      { 
 
        result = UploadStatus.Upload_New_File_Failed; 
 
      } 
 
      is.close(); 
 
    } else 
    { 
 
      InputStream is = new FileInputStream(local); 
 
      if (ftpClient.storeFile(remoteFileName, is)) 
      { 
 
        result = UploadStatus.Upload_New_File_Success; 
 
      } else 
      { 
 
        result = UploadStatus.Upload_New_File_Failed; 
 
      } 
 
      is.close(); 
    } 
 
    return result; 
 
  } 
 
  /** 
   * 
   * 断开与远程服务器的连接 
   * 
   * @throws IOException 
   */ 
 
  public void disconnect() throws IOException 
  { 
 
    if (ftpClient.isConnected()) 
    { 
      ftpClient.disconnect(); 
    } 
 
  } 
 
  public static void main(String[] args) 
  { 
    ContinueFTP myFtp = new ContinueFTP(); 
    try 
    { 
 
      myFtp.connect("192.168.1.200", 21, "duser", "HTPDuserXP32"); 
 
      System.out.println(myFtp.upload("C:\\Users\\Administrator\\Desktop\\swing.drawer.jar", "/jars/swing.drawer.jar")); 
 
      myFtp.disconnect(); 
 
    } catch (IOException e) 
    { 
 
      System.out.println("连接FTP出错:" + e.getMessage()); 
 
    } 
 
  } 
 
} 

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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