java大数据处理-千万级FTP下载

# DS_LIST_CMD = NLST

publicFile sendNlistAndListToFile(String command,String localPathName)throwsIOException

{

try{

returnclient.createFile(command, localPathName);

}catch(IOException e) {

log.error(e);

thrownewIOException("the command "+command +" is incorrect");

}

}

FTPFile[] dirList = client.listFiles();

client.enterLocalPassiveMode();// 设置为被动模式

ftpclient.binary();// 一定要使用二进制模式

/** 下载所需的文件并支持断点续传,下载后删除FTP文件，以免重复

* @param pathName 远程文件

* @param localPath 本地文件

* @param registerFileName 记录本文件名称目录

* @param size 上传文件大小

* @return true 下载及删除成功

* @throws IOException

* @throws Exception

*/

publicbooleandownLoad(String pathName, String localPath)throwsIOException {

booleanflag =false;

File file =newFile(localPath+".tmp");//设置临时文件

FileOutputStream out =null;

try{

client.enterLocalPassiveMode();// 设置为被动模式

client.setFileType(FTP.BINARY_FILE_TYPE);//设置为二进制传输

if(lff.getIsFileExists(file)){//判断本地文件是否存在，如果存在并且长度小于FTP文件的长度时断点续传;返之新增

longsize =this.getSize(pathName);

longlocalFileSize = lff.getSize(file);

if(localFileSize > size){

returnfalse;

}

out =newFileOutputStream(file,true);

client.setRestartOffset(localFileSize);

flag = client.retrieveFile(newString(pathName.getBytes(),client.getControlEncoding()),out);

out.flush();

}else{

out =newFileOutputStream(file);

flag = client.retrieveFile(newString(pathName.getBytes(),client.getControlEncoding()),out);

out.flush();

}

}catch(IOException e){

log.error(e);

log.error("file download error !");

throwe;

}finally{

try{

if(null!=out)

out.close();

if(flag)

lff.rename(file, localPath);

}catch(IOException e){

throwe;

}

}

returnflag;

}

/**

* 获取文件长度

* @param fileNamepath 本机文件

* @return

* @throws IOException

*/

publiclonggetSize(String fileNamepath)throwsIOException{

FTPFile [] ftp = client.listFiles(newString(fileNamepath.getBytes(),client.getControlEncoding()));

returnftp.length==0?0: ftp[0].getSize();

}

检测本地文件是否已经下载，如果下载文件的大小.

/**

*获取文件的大小

* @param file

* @return

*/

publiclonggetSize(File file){

longsize =0;

if(getIsFileExists(file)){

size = file.length();

}

returnsize;

}

//linux aix There is not enough space in the file system

// window There is not enough space in the file system

if(e.toString().contains("enough space")||e.toString().contains("磁盘空间已满"))

{

log.error(" There is not enough space on the disk ");

Runtime.getRuntime().exit(0);

}