java实现ftp上传下载功能

    common-net（http://commons.apache.org/proper/commons-net/）是一个比较实用的开源组件，可以基于common-net实现许多比较实用的功能，比如说ssh、ftp、smtp 等等，先来说说比较简单的ftp功能的实现。

    基于common-net实现ftp的功能，需要先获取FTPClient对象，利用FTPClient对象的public boolean retrieveFile(String remote, OutputStream local)方法实现文件下载功能，利用public boolean storeFile(String remote, InputStream local)方法实现文件上传功能。

    下面是我写的一个简单的demo：

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
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.net.SocketException;
import org.apache.commons.net.ftp.FTPClient;


public class FtpTest {
	
	public FtpTest(String userName,String password,String ip){
		this.userName = userName;
		this.password = password;
		this.ip = ip;
	}
	
	/**
	 * 上传文件
	 * 
	 * @param File f 要上传的文件
	 * @param String uploadDir 上传文件的路径
	 * 
	 * @return boolean b 上传结果
	 * */
	public boolean putFile(File f,String uploadDir) {
		InputStream instream = null;
		boolean result = false;
		try{
			try{
				ftpClient.changeWorkingDirectory(uploadDir);
				instream = new BufferedInputStream(new FileInputStream(f));
				result = ftpClient.storeFile(f.getName(), instream);
			}finally{
				if(instream!=null){
					instream.close();
				}
			}
		}catch(IOException e){
			e.printStackTrace();
		}
		
		return result;
	}
	
	/**
	 * 从ftp服务器下载文件
	 * 
	 * @param File f 要获取的ftp服务器上的文件
	 * @param String localPath 本地存放的路径
	 * 
	 * @return boolean 文件下载是否成功
	 * */
	public boolean getFile(File f  , String localPath){
		OutputStream outStream = null;
		boolean result = false;
		try{
			try{
				outStream = new BufferedOutputStream(new FileOutputStream(new File(localPath)));
				String path = f.getPath();
				path = path.replaceAll("\\\\", "/");
				String filepath = path.substring(0, path.lastIndexOf("/")+1)+"";
				String fileName = path.substring(path.lastIndexOf("/")+1)+"";
				boolean b = ftpClient.changeWorkingDirectory(filepath);
				if(b){
					result = ftpClient.retrieveFile(fileName, outStream);
				}
			}finally{
				if(outStream != null){
					outStream.close();
				}
			}
		}catch(IOException e){
			e.printStackTrace();
		}
		return result;
	}
	/**
	 * 获取ftp链接
	 * 
	 * @return ftpClient
	 * */
	public FTPClient getFTPClient(){
		
		try {
			ftpClient = new FTPClient();

			ftpClient.connect(ip);
			ftpClient.login(userName, password);
		} catch (SocketException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return ftpClient;
	}
	
	/**
	 *  关闭ftpClient链接
	 *  
	 *  @param FTPClient 要关闭的ftpClient对象
	 *  
	 * */
	public void closeFTPClient(FTPClient ftpClient){
		try {
			try{
				ftpClient.logout();
			}finally{
				ftpClient.disconnect();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	/*ftp用户名*/
	private String userName;
	/*ftp密码*/
	private String password;
	/*ftp服务器ip*/
	private String ip;
	private FTPClient ftpClient;
}