【FTP】FTP文件上传下载-支持断点续传

Jar包：apache的commons-net包；

支持断点续传
支持进度监控(有时出不来，搞不清原因)

相关知识点

编码格式: UTF-8等;

文件类型： 包括[BINARY_FILE_TYPE(常用)]和[ASCII_FILE_TYPE]两种;

数据连接模式：一般使用LocalPassiveMode模式，因为大部分客户端都在防火墙后面；

1. LocalPassiveMode：服务器端打开数据端口，进行数据传输；2. LocalActiveMode：客户端打开数据端口，进行数据传输；系统类型：UNIX/WINDOWS等，默认为Unix

流程

步骤1： 创建FTPClient对象，设置ftpClient属性：如编码格式、连接超时、文件上传下载进度监听器等;

步骤2： 使用ftpClient连接远程server：connect()；

步骤3： 获取connect()的返回码getReplyCode()，判断是否连接成功：isPositiveCompletion()；

步骤4： 登录远程server：login(),并转到相应目录，必要时要递归创建目录;

步骤5： 设置ftpClient属性：如缓存大小、文件类型、超时时间、数据连接模式等；

步骤6： ftp相关操作：如文件上传、下载等；

步骤7： 断开连接，释放资源：logout()/disconnect();

程序

FTP连接和登录

文件上传

文件下载

测试程序

完整程序

package com.sssppp.Communication;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.io.RandomAccessFile;

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.FTPClientConfig;

import org.apache.commons.net.ftp.FTPFile;

import org.apache.commons.net.ftp.FTPReply;

import org.apache.commons.net.io.CopyStreamEvent;

import org.apache.commons.net.io.CopyStreamListener;

/**

* FTP进行文件上传和下载；

* 支持断点续传；

*/

public final class FTPUtil {

private final FTPClient ftp = new FTPClient();

/**

*

*@param hostname

* 如：IP

*@param port

*@param username

*@param password

*@return

*@throws IOException

*/

public boolean connect(String hostname, int port, String username,

String password) throws IOException {

boolean debug = false;

if (debug) {

// 设置将过程中使用到的命令输出到控制台

this.ftp.addProtocolCommandListener(new PrintCommandListener(

new PrintWriter(System.out), true));

}

//设置系统类型

final FTPClientConfig config = new FTPClientConfig(

FTPClientConfig.SYST_UNIX);

this.ftp.configure(config);

try {

this.ftp.connect(hostname, port);

if (!FTPReply.isPositiveCompletion(this.ftp.getReplyCode())) {

this.ftp.disconnect();

System.err.println("FTP server refused connection.");

return false;

}

} catch (IOException e) {

if (this.ftp.isConnected()) {

try {

this.ftp.disconnect();

} catch (IOException f) {

}

}

System.err.println("Could not connect to server.");

e.printStackTrace();

return false;

}

if (!this.ftp.login(username, password)) {

this.ftp.logout();

System.err.println("Could not login to server.");

return false;

}

return true;

}

public void disconnect() throws IOException {

if (this.ftp.isConnected()) {

try {

this.ftp.logout();

this.ftp.disconnect();

} catch (IOException f) {

}

}

}

/**

*

*@param absSrcFileName

*@param destDir

*@param destFileName

*@throws IOException

*/

public void upLoadByFtp(String absSrcFileName, String destDir,

String destFileName) throws IOException {

// 创建并转到工作目录

String absDstDir = this.ftp.printWorkingDirectory() + "/" + destDir;

absDstDir = absDstDir.replaceAll("//", "/");

createDirectory(absDstDir, this.ftp);

// 设置各种属性

this.ftp.setFileType(FTP.BINARY_FILE_TYPE);

// Use passive mode as default because most of us are behind firewalls these days.

this.ftp.enterLocalPassiveMode();

this.ftp.setControlEncoding("utf-8");

this.ftp.setBufferSize(1024);

// 进度监听

File srcFile = new File(absSrcFileName);

this.ftp.setCopyStreamListener(new MyCopyStreamListener(srcFile.length()));

FTPFile[] files = this.ftp.listFiles(destFileName);

if (files.length == 1) {// 断点续传

long dstFileSize = files[0].getSize();

if (srcFile.length() <= dstFileSize) {// 文件已存在

return;

}

boolean b = uploadFile(destFileName, srcFile, this.ftp, dstFileSize);

if (!b) {// 如果断点续传没有成功，则删除服务器上文件，重新上传

if (this.ftp.deleteFile(destFileName)) {

uploadFile(destFileName, srcFile, this.ftp, 0);

}else {

System.err.println("Delete file fail.");

}

}

} else {

uploadFile(destFileName, srcFile, this.ftp, 0);

}

}

/**

*

*@param remoteFileName

*@param localFileName

*@throws IOException

*/

public void downLoadByFtp(String remoteFileName, String localFileName)

throws IOException {

InputStream input = null;

FileOutputStream fos = null;

// 设置各种属性

this.ftp.setBufferSize(1024);

this.ftp.setDataTimeout(1000 * 10);

this.ftp.setFileType(FTPClient.BINARY_FILE_TYPE);

this.ftp.enterLocalPassiveMode();

// 判断远程文件是否存在

FTPFile[] files = this.ftp.listFiles(remoteFileName);

if (files.length != 1) {

System.err.println("Remote file not exist.");

return;

}

//进度监听

long remoteSize = files[0].getSize();

this.ftp.setCopyStreamListener(new MyCopyStreamListener(remoteSize));

File file = new File(localFileName);

if (file.exists()) {

long localSize = file.length();

if (localSize >= remoteSize) {

return;

}

System.out.println("@@@Break point download.@@@");

fos = new FileOutputStream(file, true);// append模式

this.ftp.setRestartOffset(localSize);

} else {

fos = new FileOutputStream(file); // override模式

}

input = this.ftp.retrieveFileStream(remoteFileName);

byte[] b = new byte[8192];

int n = 0;

while (-1 != (n = input.read(b))) {

if (Thread.currentThread().isInterrupted()) {

break;

}

fos.write(b, 0, n);

}

if (input != null) {

input.close();

}

if (fos != null) {

fos.flush();

fos.close();

}

if (!this.ftp.completePendingCommand()) {

System.err.println("Download file fail.");

this.ftp.logout();

this.ftp.disconnect();

}

}

/**

*

*@param destFileName

*@param srcFile

*@param ftpClient

*@param dstFileSize 文件写入的起始位置； >0:表示断点续传，<=0:表示上传新文件

*@return

*@throws IOException

*/

private boolean uploadFile(String destFileName, File srcFile,

FTPClient ftpClient, long dstFileSize) throws IOException {

RandomAccessFile input = null;

OutputStream fout = null;

input = new RandomAccessFile(srcFile, "r"); // 只读模式

if (dstFileSize > 0) {// 断点续传

fout = ftpClient.appendFileStream(destFileName);

input.seek(dstFileSize);

ftpClient.setRestartOffset(dstFileSize);

} else {

fout = ftpClient.storeFileStream(destFileName);

}

byte[] b = new byte[8192]; // 缓存大小

int n = 0;

while (-1 != (n = input.read(b))) {

if (Thread.currentThread().isInterrupted()) {

break;

}

fout.write(b, 0, n);

}

if (input != null) {

input.close();

}

if (fout != null) {

fout.flush();

fout.close();

}

if (!ftpClient.completePendingCommand()) {

System.err.println("Upload file fail.");

ftpClient.logout();

ftpClient.disconnect();

return false;

}

return true;

}

/**

*在FTP服务器上创建并转到工作目录

*

*@param relativePath

* 相对工作路径，不包含文件名：如 dd/11/22/33

*@param ftpClient

* 录创建是否成功

*@return

*@throws IOException

*/

private boolean createDirectory(String relativePath, FTPClient ftpClient)

throws IOException {

if (!relativePath.startsWith("/")) {

relativePath = "/" + relativePath;

}

String dir = (ftpClient.printWorkingDirectory().equals("/") ? ""

: ftpClient.printWorkingDirectory()) + relativePath;

if (!ftpClient.changeWorkingDirectory(dir)) {

//目录不存在，则创建各级目录

for (String subDir : relativePath.split("/")) {

if (!subDir.equals("")) {

String newDir = ftpClient.printWorkingDirectory() + "/"

+ subDir;

ftpClient.mkd(newDir);

if (!ftpClient.changeWorkingDirectory(newDir)) {

return false;

}

}

}

}

return true;

}

/**

*进度监听器

*/

private class MyCopyStreamListener implements CopyStreamListener {

private long totalSize = 0;

private long percent = -1; // 进度

/**

*文件的总大小

*@param totalSize

 */

public MyCopyStreamListener(long totalSize) {

super();

this.totalSize = totalSize;

}

@Override

public void bytesTransferred(CopyStreamEvent event) {

bytesTransferred(event.getTotalBytesTransferred(),

event.getBytesTransferred(), event.getStreamSize());

}

//totalBytesTransferred:当前总共已传输字节数;

//bytesTransferred:最近一次传输字节数

@Override

public void bytesTransferred(long totalBytesTransferred,

int bytesTransferred, long streamSize) {

if (percent >= totalBytesTransferred * 100 / totalSize) {

return;

}

percent = totalBytesTransferred * 100 / totalSize;

System.out.println("Completed " + totalBytesTransferred + "("

+ percent + "%) out of " + totalSize + ".");

}

}

public static void main(String[] args) throws IOException {

String hostname = "10.180.137.241";

String username = "xxx";

String password = "xxx";

int port = 21;

FTPUtil ftp = new FTPUtil();

//上传文件

String absSrcFileName = "C:\\tmp\\m2eclipse1.zip";

String destDir = "ww/11/22/33";

String destFileName = "m2eclipse1.zip";

ftp.connect(hostname, port, username, password);

ftp.upLoadByFtp(absSrcFileName, destDir, destFileName);

ftp.disconnect();

// 下载文件

String localFileName = "C:\\tmp\\m2eclipse-download3333.zip";

String remoteFileName = "/ww/11/22/33/m2eclipse.zip";

ftp.connect(hostname, port, username, password);

ftp.downLoadByFtp(remoteFileName, localFileName);

ftp.disconnect();

}

}

[/code]

参考链接

官方Demo： http://commons.apache.org/proper/commons-net/examples/ftp/FTPClientExample.java https://my.oschina.net/csmw00/blog/676049 （可参考如何实现进度监控）http://yujie020.blog.51cto.com/2827685/655338

来自为知笔记(Wiz)