如何在java中使用SFTP协议安全的传输文件

<dependency>
  <groupId>com.jcraft</groupId>
  <artifactId>jsch</artifactId>
  <version>0.1.55</version>
</dependency>

JSch jsch = new JSch();
jsch.setKnownHosts("/home/zimug/.ssh/known_hosts");
jschSession = jsch.getSession(USERNAME, REMOTE_HOST, REMOTE_PORT);

jschSession.setPassword(PASSWORD);

JSch jsch = new JSch();
jsch.setKnownHosts("/home/zimug/.ssh/known_hosts");
jschSession = jsch.getSession(USERNAME, REMOTE_HOST, REMOTE_PORT);

jsch.addIdentity("/home/zimug/.ssh/id_rsa");

import com.jcraft.jsch.*;

public class SFTPFileTransfer {

  private static final String REMOTE_HOST = "1.2.3.4"; //远程主机ip
  private static final String USERNAME = ""; //登录用户名
  private static final String PASSWORD = ""; //登陆密码
  private static final int REMOTE_PORT = 22;  //ssh协议默认端口
  private static final int SESSION_TIMEOUT = 10000; //session超时时间
  private static final int CHANNEL_TIMEOUT = 5000; //管道流超时时间

  public static void main(String[] args) {

    String localFile = "/home/zimug/local/random.txt";  //本地文件路径
    String remoteFile = "/home/zimug/remote/targetfile.txt";  //上传到远程的文件路径，要保证登录用户有写权限

    Session jschSession = null;

    try {

      JSch jsch = new JSch();
      jsch.setKnownHosts("/home/zimug/.ssh/known_hosts");
      jschSession = jsch.getSession(USERNAME, REMOTE_HOST, REMOTE_PORT);

      // 通过ssh私钥的方式登录认证
      // jsch.addIdentity("/home/zimug/.ssh/id_rsa");

      // 通过密码的方式登录认证
      jschSession.setPassword(PASSWORD);
      jschSession.connect(SESSION_TIMEOUT);

      Channel sftp = jschSession.openChannel("sftp"); //建立sftp文件传输管道
      sftp.connect(CHANNEL_TIMEOUT);

      ChannelSftp channelSftp = (ChannelSftp) sftp;

      // 传输本地文件到远程主机
      channelSftp.put(localFile, remoteFile);

      channelSftp.exit();

    } catch (JSchException | SftpException e) {
      e.printStackTrace();
    } finally {
      if (jschSession != null) {
        jschSession.disconnect();
      }
    }
    System.out.println("文件传输完成！");
  }
}

com.jcraft.jsch.JSchException: Auth fail
	at com.jcraft.jsch.Session.connect(Session.java:519)
	at com.zimug.io.howto.SFTPFileTransfer.main(SFTPFileTransfer.java:34)