java实现ftp下文件的上传、下载和删除

有时候项目需要对服务器的文件进行操作，如下是我在项目中的应用：
需要的包为：

<dependency>      <groupId>com.jcraft</groupId>       <artifactId>jsch</artifactId>       <version>0.1.49</version> </dependency>

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;import java.io.*;import java.util.Properties;import java.util.Vector;public class FileTool {    /**     * 上传文件到ftp服务器     * @param host ftp服务器地址     * @param port ftp服务器端口号     * @param username ftp登录账号     * @param password ftp登录密码     * @param dir 保存文件的ftp目录     * @param filename 保存在ftp里的文件名     * @param originfilename 上传文件的名称（绝对地址）     * @return     */    public static boolean uploadFile(String host, int port, String username, final String password, String dir,                                             String filename,                                             String originfilename ) {        boolean flag = false;        ChannelSftp sftp = null;        Channel channel = null;        Session sshSession = null;        try {            JSch jsch = new JSch();            jsch.getSession(username, host, port);            sshSession = jsch.getSession(username, host, port);            sshSession.setPassword(password);            Properties sshConfig = new Properties();            sshConfig.put("StrictHostKeyChecking", "no");            sshSession.setConfig(sshConfig);            sshSession.connect();            channel = sshSession.openChannel("sftp");            channel.connect();            sftp = (ChannelSftp) channel;            if(sftp.ls(dir).size()==0){                sftp.mkdir(dir);            }            sftp.cd(dir);            InputStream inputStream = new FileInputStream(new File(originfilename));            sftp.put(inputStream,filename);            inputStream.close();            flag = true;        } catch (Exception e) {            e.printStackTrace();        } finally {            closeChannel(sftp);            closeChannel(channel);            closeSession(sshSession);        }        return flag;    }    /**     * 从服务器下载文件     * @param host ftp服务器地址     * @param port ftp服务器端口号     * @param username ftp登录账号     * @param password ftp登录密码     * @param dir 保存文件的ftp目录     * @param filename 保存在ftp里的文件名     * @param localPath 保存文件到本地的目录     * @return     */    public static boolean downloadFile(String host, int port, String username, final String password, String dir,                                     String filename,                                     String localPath) {        boolean flag = false;        ChannelSftp sftp = null;        Channel channel = null;        Session sshSession = null;        try {            JSch jsch = new JSch();            jsch.getSession(username, host, port);            sshSession = jsch.getSession(username, host, port);            sshSession.setPassword(password);            Properties sshConfig = new Properties();            sshConfig.put("StrictHostKeyChecking", "no");            sshSession.setConfig(sshConfig);            sshSession.connect();            channel = sshSession.openChannel("sftp");            channel.connect();            sftp = (ChannelSftp) channel;            sftp.setFilenameEncoding("UTF-8");            sftp.cd(dir);            Vector<?> vector = sftp.ls(dir);            for (Object item:vector) {                LsEntry entry = (LsEntry) item;                if(filename.equals(entry.getFilename())){                    File localFile = new File(localPath + File.separatorChar+ entry.getFilename());                    OutputStream os = new FileOutputStream(localFile);                    System.out.println(os);                    sftp.get(filename,os);                    os.close();                }                System.out.println(entry.getFilename());            }            flag = true;        } catch (Exception e) {            e.printStackTrace();        } finally {            closeChannel(sftp);            closeChannel(channel);            closeSession(sshSession);        }        return flag;    }    /**     * 删除服务器上的文件     * @param host     * @param port     * @param username     * @param password     * @param dir 删除文件的ftp路径     * @param filename 文件名     * @return     */    public static boolean deleteFile(String host, int port, String username, final String password, String dir,                                     String filename){        boolean flag=false;        ChannelSftp sftp = null;        Channel channel = null;        Session sshSession = null;        try {            JSch jsch = new JSch();            jsch.getSession(username, host, port);            sshSession = jsch.getSession(username, host, port);            sshSession.setPassword(password);            Properties sshConfig = new Properties();            sshConfig.put("StrictHostKeyChecking", "no");            sshSession.setConfig(sshConfig);            sshSession.connect();            channel = sshSession.openChannel("sftp");            channel.connect();            sftp = (ChannelSftp) channel;            if(sftp.ls(dir).size()==0){                sftp.mkdir(dir);            }            sftp.cd(dir);            sftp.rm(dir+"/"+filename+".jpg");            flag = true;        } catch (Exception e) {            e.printStackTrace();        } finally {            closeChannel(sftp);            closeChannel(channel);            closeSession(sshSession);        }        return flag;    }    public static void closeChannel(Channel channel) {        if (channel != null) {            if (channel.isConnected()) {                channel.disconnect();            }        }    }    public static void closeSession(Session session) {        if (session != null) {            if (session.isConnected()) {                session.disconnect();            }        }    }}

在用的时候直接调用即可：

FileTool.downloadFile("127.0.0.0",22,"root","root","/usr/tomcat/webapps/99jiaeduLogo","1231243.jpg","d:\99jiaeduLogo");

FileTool.uploadFile("127.0.0.0",22,"root","root","/usr/tomcat/webapps/99jiaeduLogo","1231243.jpg","d:\99jiaeduLogo");

FileTool.deleteFile("127.0.0.0",22,"root","root","/usr/tomcat/webapps/99jiaeduLogo","12314134134");