使用Java连接到远程计算机时出现连接拒绝错误

使用Java连接到远程计算机时出现以下错误：我尝试连接远程，然后执行命令

错误

com.jcraft.jsch.JSchException: java.net.ConnectException: Connection refused: connect

码

  ```js

session = jsch.getSession(user, host, 22); session.setPassword(password); session.setConfig("StrictHostKeyChecking", "no"); session.setConfig("PreferredAuthentications", "publickey,keyboard-interactive,password"); session.connect();

    Channel channel = session.openChannel("exec");
    ((ChannelExec) channel).setCommand(command_to_execute);
    channel.setInputStream(null);
    ((ChannelExec) channel).setErrStream(System.err);

    InputStream in = channel.getInputStream();
    channel.connect();

    BufferedReader reader = new BufferedReader(new 
    InputStreamReader(in));
    String line;
    int index = 0;
    channel.disconnect();
    session.disconnect();