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：
我要评论
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移动技术网。
如对本文有疑问， 点击进行留言回复！！
![[杭电多校2020]第一场 1004 Distinct Sub-palindromes](http://www.lhsxpumps.com/_images5/10qianwan/20200724/s_0_202007241733388592.png)
[杭电多校2020]第一场 1004 Distinct Sub-palindromes
Swift -- 将本地生成的UIImage进行持久化保存（存到文件中fileManager.createFile）
网友评论