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());
}
}
}
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