FTP断点续传案例以及多线程下载的Demo

FTP断点续传案例以及多线程下载的Demo

在使用FTP的过程中，很多时候需要系统支持断点续传以及多线程下载，前段时间为了做这个功能，各种搜索，综合了一下，写了一个demo，给正在写FTP的童鞋一点启发。源码下载地址会附在文章末尾，源码中包含文件传输的多种方式，网络文件传输，本地文件传输，FTP文件传输，以及多线程下载和断点续传，多线程断点续传，每个包对应一种方式，需要的自行查看哪个包是哪种类型

上代码：
文件上传下载的类：

package com.shallowdream.threaddemo;

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

/**
 * 支持断点续传的FTP实用类
 * @author BenZhou
 * @version 0.1 实现基本断点上传下载
 * @version 0.2 实现上传下载进度汇报
 * @version 0.3 实现中文目录创建及中文文件创建，添加对于中文的支持
 */
public class ContinueFtp {
    public FTPClient ftpClient = new FTPClient();

    public ContinueFtp(){
        //设置将过程中使用到的命令输出到控制台
        this.ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));
    }
    /**
     * 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);
        ftpClient.setControlEncoding("GBK");
        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,支持断点续传，上传百分比汇报
     * @param remote 远程文件路径
     * @param local 本地文件路径
     * @return 上传的状态
     * @throws IOException
     */
    public DownloadStatus download(String remote,String local) throws IOException{
        //设置被动模式
        ftpClient.enterLocalPassiveMode();
        //设置以二进制方式传输
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
        DownloadStatus result;

        //检查远程文件是否存在
        FTPFile[] files = ftpClient.listFiles(new String(remote.getBytes("GBK"),"iso-8859-1"));
        if(files.length != 1){
            System.out.println("远程文件不存在");
            return DownloadStatus.Remote_File_Noexist;
        }

        long lRemoteSize = files[0].getSize();
        File f = new File(local);
        //本地存在文件，进行断点下载
        if(f.exists()){
            long localSize = f.length();
            //判断本地文件大小是否大于远程文件大小
            if(localSize >= lRemoteSize){
                System.out.println("本地文件大于远程文件，下载中止");
                return DownloadStatus.Local_Bigger_Remote;
            }

            //进行断点续传，并记录状态
            FileOutputStream out = new FileOutputStream(f,true);
            ftpClient.setRestartOffset(localSize);
            InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("GBK"),"iso-8859-1"));
            byte[] bytes = new byte[1024];
            long step = lRemoteSize /100;
            long process=localSize /step;
            int c;
            while((c = in.read(bytes))!= -1){
                out.write(bytes,0,c);
                localSize+=c;
                long nowProcess = localSize /step;
                if(nowProcess > process){
                    process = nowProcess;
                        System.out.println("下载进度："+process+"%");
                        //TODO 更新文件下载进度,值存放在process变量中
                }
            }
            in.close();
            out.close();
            boolean isDo = ftpClient.completePendingCommand();
            if(isDo){
                result = DownloadStatus.Download_From_Break_Success;
            }else {
                result = DownloadStatus.Download_From_Break_Failed;
            }
        }else {
            OutputStream out = new FileOutputStream(f);
            InputStream in= ftpClient.retrieveFileStream(new String(remote.getBytes("GBK"),"iso-8859-1"));
            byte[] bytes = new byte[1024];
            long step = lRemoteSize /100;
            long process=0;
            long localSize = 0L;
            int c;
            while((c = in.read(bytes))!= -1){
                out.write(bytes, 0, c);
                localSize+=c;
                long nowProcess = localSize /step;
                if(nowProcess > process){
                    process = nowProcess;
                        System.out.println("下载进度："+process);
                        //TODO 更新文件下载进度,值存放在process变量中
                }
            }
            in.close();
            out.close();
            boolean upNewStatus = ftpClient.completePendingCommand();
            if(upNewStatus){
                result = DownloadStatus.Download_New_Success;
            }else {
                result = DownloadStatus.Download_New_Failed;
            }
        }
        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
     */
    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);
        ftpClient.setControlEncoding("GBK");
        UploadStatus result;
        //对远程目录的处理
        String remoteFileName = remote;
        if(remote.contains("/")){
            remoteFileName = remote.substring(remote.lastIndexOf("/")+1);
            //创建服务器远程目录结构，创建失败直接返回
            if(CreateDirecroty(remote, ftpClient)==UploadStatus.Create_Directory_Fail){
                return UploadStatus.Create_Directory_Fail;
            }
        }

        //检查远程是否存在文件
        FTPFile[] files = ftpClient.listFiles(new String(remoteFileName.getBytes("GBK"),"iso-8859-1"));
        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
            result = uploadFile(remoteFileName, f, ftpClient, remoteSize);

            //如果断点续传没有成功，则删除服务器上文件，重新上传
            if(result == UploadStatus.Upload_From_Break_Failed){
                if(!ftpClient.deleteFile(remoteFileName)){
                    return UploadStatus.Delete_Remote_Faild;
                }
                result = uploadFile(remoteFileName, f, ftpClient, 0);
            }
        }else {
            result = uploadFile(remoteFileName, new File(local), ftpClient, 0);
        }
        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();
        }
    }

    /**
     * 递归创建远程服务器目录
     * @param remote 远程服务器文件绝对路径
     * @param ftpClient FTPClient对象
     * @return 目录创建是否成功
     * @throws IOException
     */
    public UploadStatus CreateDirecroty(String remote,FTPClient ftpClient) throws IOException{
        UploadStatus status = UploadStatus.Create_Directory_Success;
        String directory = remote.substring(0,remote.lastIndexOf("/")+1);
        if(!directory.equalsIgnoreCase("/")&&!ftpClient.changeWorkingDirectory(new String(directory.getBytes("GBK"),"iso-8859-1"))){
            //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 = new String(remote.substring(start,end).getBytes("GBK"),"iso-8859-1");
                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;
                }
            }
        }
        return status;
    }

    /**
     * 上传文件到服务器,新上传和断点续传
     * @param remoteFile 远程文件名，在上传之前已经将服务器工作目录做了改变
     * @param localFile 本地文件File句柄，绝对路径
     * @param ftpClient FTPClient引用
     * @throws IOException
     */
    public UploadStatus uploadFile(String remoteFile,File localFile,FTPClient ftpClient,long remoteSize) throws IOException{
        UploadStatus status;
        //显示进度的上传
        long step = localFile.length() / 100;
        long process = 0;
        long localreadbytes = 0L;
        RandomAccessFile raf = new RandomAccessFile(localFile,"r");
        OutputStream out = ftpClient.appendFileStream(new String(remoteFile.getBytes("GBK"),"iso-8859-1"));
        //断点续传
        if(remoteSize>0){
            ftpClient.setRestartOffset(remoteSize);
            process = remoteSize /step;
            raf.seek(remoteSize);
            localreadbytes = remoteSize;
        }
        byte[] bytes = new byte[1024];
        int c;
        while((c = raf.read(bytes))!= -1){
            out.write(bytes,0,c);
            localreadbytes+=c;
            if(localreadbytes / step != process){
                process = localreadbytes / step;
                System.out.println("上传进度:" + process);
            }
        }
        out.flush();
        raf.close();
        out.close();
        boolean result =ftpClient.completePendingCommand();
        if(remoteSize > 0){
            status = result?UploadStatus.Upload_From_Break_Success:UploadStatus.Upload_From_Break_Failed;
        }else {
            status = result?UploadStatus.Upload_New_File_Success:UploadStatus.Upload_New_File_Failed;
        }
        return status;
    }

    public static void main(String[] args) {
        ContinueFtp myFtp = new ContinueFtp();
        try {
            myFtp.connect("10.2.15.54", 2121, "test", "test");
            System.out.println(myFtp.download("11\\33\\11.iso", "E:\\11.iso"));
            myFtp.disconnect();
        } catch (IOException e) {
            System.out.println("连接FTP出错："+e.getMessage());
        }
    }
}

枚举类：

package com.shallowdream.threaddemo;

public enum DownloadStatus {
    Remote_File_Noexist, //远程文件不存在
    Local_Bigger_Remote, //本地文件大于远程文件
    Download_From_Break_Success, //断点下载文件成功
    Download_From_Break_Failed, //断点下载文件失败
    Download_New_Success, //全新下载文件成功
    Download_New_Failed; //全新下载文件失败
}

package com.shallowdream.threaddemo;

public enum UploadStatus {
    Create_Directory_Fail, //远程服务器相应目录创建失败
    Create_Directory_Success, //远程服务器闯将目录成功
    Upload_New_File_Success, //上传新文件成功
    Upload_New_File_Failed, //上传新文件失败
    File_Exits, //文件已经存在
    Remote_Bigger_Local, //远程文件大于本地文件
    Upload_From_Break_Success, //断点续传成功
    Upload_From_Break_Failed, //断点续传失败
    Delete_Remote_Faild; //删除远程文件失败
}

以上代码是FTP断点续传的代码，多线程下载的demo一并发在源码里边，源码下载地址：
源码下载
若有不足之处还望指正！