最近做了一个sftp服务器文件下载的功能，mark一下：首先是一个SftpClientUtil 类，封装了对sftp服务器文件上传、下载、删除的方法import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.Vector;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.ChannelSftp.LsEntry;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;public class SftpClientUtil {/**
* 初始化日志引擎
*/
private final Logger logger = LoggerFactory.getLogger(SftpClientUtil.class);/** Sftp */
ChannelSftp sftp = null;
/** 主机 */private String host = "";/** 端口 */private int port = 0;/** 用户名 */private String username = "";/** 密码 */private String password = "";/**
* 构造函数
*
* @param host
*            主机
* @param port
*            端口
* @param username
*            用户名
* @param password
*            密码
*
*/public SftpClientUtil(String host, int port, String username,
String password){this.host = host;this.port = port;this.username = username;this.password = password;}/**
* 连接sftp服务器
*
* @throws Exception
*/
public void connect() throws Exception {JSch jsch = new JSch();
Session sshSession = jsch.getSession(this.username, this.host, this.port);
logger.debug(SftpClientUtil.class + "Session created.");sshSession.setPassword(password);
Properties sshConfig = new Properties();
sshConfig.put("StrictHostKeyChecking", "no");
sshSession.setConfig(sshConfig);
sshSession.connect(20000);
logger.debug(SftpClientUtil.class + " Session connected.");logger.debug(SftpClientUtil.class + " Opening Channel.");
Channel channel = sshSession.openChannel("sftp");
channel.connect();
this.sftp = (ChannelSftp) channel;
logger.debug(SftpClientUtil.class + " Connected to " + this.host + ".");
}/*** Disconnect with server
*
* @throws Exception
*/public void disconnect() throws Exception {if(this.sftp != null){if(this.sftp.isConnected()){this.sftp.disconnect();}else if(this.sftp.isClosed()){logger.debug(SftpClientUtil.class + " sftp is closed already");}}}/**
* 上传单个文件
*
* @param directory
*            上传的目录
* @param uploadFile
*            要上传的文件
*
* @throws Exception
*/
public void upload(String directory, String uploadFile) throws Exception {
this.sftp.cd(directory);
File file = new File(uploadFile);
this.sftp.put(new FileInputStream(file), file.getName());
}/**
* 上传目录下全部文件
*
* @param directory
*            上传的目录
*
* @throws Exception
*/
public void uploadByDirectory(String directory) throws Exception {String uploadFile = "";
List<String> uploadFileList = this.listFiles(directory);
Iterator<String> it = uploadFileList.iterator();while(it.hasNext())
{
uploadFile = it.next().toString();
this.upload(directory, uploadFile);
}
}/**
* 下载单个文件
*
* @param directory
*            下载目录
* @param downloadFile
*            下载的文件
* @param saveDirectory
*            存在本地的路径
*
* @throws Exception
*/
public void download(String directory, String downloadFile, String saveDirectory) throws Exception {
String saveFile = saveDirectory + "//" + downloadFile;this.sftp.cd(directory);
File file = new File(saveFile);
this.sftp.get(downloadFile, new FileOutputStream(file));
}/**
* 下载目录下全部文件
*
* @param directory
*            下载目录
*
* @param saveDirectory
*            存在本地的路径
*
* @throws Exception
*/
public void downloadByDirectory(String directory, String saveDirectory) throws Exception {
String downloadFile = "";
List<String> downloadFileList = this.listFiles(directory);
Iterator<String> it = downloadFileList.iterator();while(it.hasNext())
{
downloadFile = it.next().toString();
if(downloadFile.toString().indexOf(".")<0){
continue;
}
this.download(directory, downloadFile, saveDirectory);
}
}/**
* 删除文件
*
* @param directory
*            要删除文件所在目录
* @param deleteFile
*            要删除的文件
*
* @throws Exception
*/
public void delete(String directory, String deleteFile) throws Exception {
this.sftp.cd(directory);
this.sftp.rm(deleteFile);
}/**
* 列出目录下的文件
*
* @param directory
*            要列出的目录
*
* @return list 文件名列表
*
* @throws Exception
*/
@SuppressWarnings("unchecked")
public List<String> listFiles(String directory) throws Exception {Vector fileList;
List<String> fileNameList = new ArrayList<String>();fileList = this.sftp.ls(directory);
Iterator it = fileList.iterator();while(it.hasNext())
{String fileName = ((LsEntry)it.next()).getFilename();if(".".equals(fileName) || "..".equals(fileName)){continue;}fileNameList.add(fileName);}return fileNameList;
}/**
* 更改文件名
*
* @param directory
*            文件所在目录
* @param oldFileNm
*            原文件名
* @param newFileNm
*            新文件名
*
* @throws Exception
*/
public void rename(String directory, String oldFileNm, String newFileNm) throws Exception {
this.sftp.cd(directory);
this.sftp.rename(oldFileNm, newFileNm);
}public void cd(String directory)throws Exception {
this.sftp.cd(directory);
}
public InputStream get(String directory) throws Exception{
InputStream streatm=this.sftp.get(directory);
return streatm;
}}其次是供jsp调用的的servlet类public class DownloadApplyPersonServlet extends HttpServlet {/** 初始化日志引擎 * */
private final Logger logger = LoggerFactory
.getLogger(DownloadApplyPersonServlet.class);public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
doPost(request, response);
}// 在doPost()方法中，当servlet收到浏览器发出的Post请求后，实现文件下载
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
logger.info("进入下载文件开始..........");
String host="";//主机地址
String port="";//主机端口
String username="";//服务器用户名
String password ="";//服务器密码
String planPath ="";//文件所在服务器路径
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
OutputStream fos = null;String fileName = "KJ_CUST_KBYJ";//KJ_CUST_KBYJ20140326.txt
SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
String currentDate =   formatter.format(new Date());
String downloadFile = fileName + currentDate + ".zip";PrintWriter out=null;
SftpClientUtil sftp = new SftpClientUtil(host, Integer.parseInt(port), username,
password);
try {
sftp.connect();
String filename="";
// String[] strs=planUrl.split("/");
String filePath=planPath;
//列出目录下的文件
List<String> listFiles=sftp.listFiles(filePath);
boolean isExists=listFiles.contains(downloadFile);
if(isExists){
sftp.cd(filePath);
if(sftp.get(downloadFile)!=null){
bis = new BufferedInputStream(sftp.get(downloadFile));
}
filename=downloadFile;
fos = response.getOutputStream();
bos = new BufferedOutputStream(fos);
response.setCharacterEncoding("UTF-8");
response.setContentType("application/x-msdownload;charset=utf-8");
final String agent = request.getHeader("User-Agent");
String attachment = "attachment;fileName=";
String outputFilename = null;if (agent.indexOf("Firefox") > 0) {
attachment = "attachment;fileName*=";
outputFilename = "=?UTF-8?B?" + (new String(Base64.encodeBase64(filename.getBytes("UTF-8")))) + "?=";;
} else {
if (agent.indexOf("MSIE") != -1) {
outputFilename = new String(filename.getBytes("gbk"), "iso8859-1");} else {
outputFilename = new String(filename.getBytes("UTF-8"), "iso8859-1");}
}
response.setHeader("Content-Disposition", attachment + outputFilename);
int bytesRead = 0;
//输入流进行先读，然后用输出流去写，下面用的是缓冲输入输出流
byte[] buffer = new byte[8192];
while ((bytesRead = bis.read(buffer)) != -1) {
bos.write(buffer,0,bytesRead);
}
bos.flush();
logger.info("文件下载成功");
}else{
response.setCharacterEncoding("utf-8");          response.setContentType("text/html; charset=UTF-8");out=response.getWriter();
out.println("<html >" +
"<body>" +
"没有找到你要下载的文件" +
"</body>" +
"</html>");
}
} catch (Exception e) {
response.setCharacterEncoding("utf-8");          response.setContentType("text/html; charset=UTF-8");out=response.getWriter();
out.println("<html >" +
"<body>" +
"没有找到你要下载的文件" +
"</body>" +
"</html>");
}finally{
try {
sftp.disconnect();
logger.info("SFTP连接已断开");
} catch (Exception e) {
e.printStackTrace();
}if(out!=null){
out.close();
}
logger.info("out已关闭");
if(bis != null){
bis.close();
}
logger.info("bis已关闭");
if(bos != null){
bos.close();
}
logger.info("bos已关闭");
}
}
}最后是对servlet的配置，具体可参考web.xml中servlet的配置。
附件中是需要用到饿jar包