高效的java ftp下载

public static boolean uploadToFtp(String url,int port,String username,String passwd,

String path,String fileName,InputStream inputStream) throws IOException{

boolean flag=false;

FTPClient ftp=new FTPClient();

try {

if(port>-1){

ftp.connect(url,port);

}else{

ftp.connect(url);//ftp默认的端口是21

}

if(ftp.login(username,passwd)){

ftp.enterLocalActiveMode();

ftp.setFileType(FTPClient.BINARY_FILE_TYPE);

//创建目录,如果存在会返回失败

ftp.makeDirectory(path);

//切换目录

ftp.changeWorkingDirectory(path);

//上传文件 

//FTP协议规定文件编码格式为ISO-8859-1

fileName=new String(fileName.getBytes(“utf-8″),”ISO-8859-1”);

OutputStream out=ftp.storeFileStream(fileName);

byte[]byteArray=new byte[4096];

int read=0;

while((read=inputStream.read(byteArray))!=-1){

out.write(byteArray,0,read);

}

out.close();

ftp.logout();

flag=true;

}

} catch (Exception e) {

e.printStackTrace();

}finally{

if(ftp.isConnected()){

ftp.disconnect();

}

}

return flag;

}



public static boolean downloadFromFtp(String url,int port,String 

username,String password,String path,String fileName,String localpath) throws IOException{

boolean flag=false;

FTPClient ftp=new FTPClient();//org.apache.commons.net.ftp

int reply;

try {

if(port>-1){

ftp.connect(url,port);

}else{

ftp.connect(url);//ftp默认的端口是21

}

//很多人写的是用ftp.getReplyCode()给获取连接的返回值,但是这样会导致storeFileStream返回null

ftp.login(username,password);

ftp.enterLocalActiveMode();

ftp.setFileType(FTPClient.BINARY_FILE_TYPE);

reply=ftp.getReplyCode();

if(!FTPReply.isPositiveCompletion(reply)){

ftp.disconnect();

return flag;

}

//切换目录 此处可以判断,切换失败就说明ftp上面没有这个路径

ftp.changeWorkingDirectory(path);

//上传文件 

OutputStream out=null;

InputStream in=null;

//创建本地的文件时候要把编码格式转回来

fileName=new String(fileName.getBytes(“ISO-8859-1″),”utf-8”);

File localFile=new File(localpath+fileName);

out=new FileOutputStream(localFile);

in=ftp.retrieveFileStream(fileName);

byte[]byteArray=new byte[4096];

int read=0;

while((read=in.read(byteArray))!=-1){

out.write(byteArray,0,read);

}

//这句很重要 要多次操作这个ftp的流的通道,要等他的每次命令完成

ftp.completePendingCommand();

out.flush();

out.close();

ftp.logout();

flag=true;

} catch(Exception e) {

e.printStackTrace();

}finally{

if(ftp.isConnected()){

ftp.disconnect();

}

}

return flag;

}