java jsch 切换用户,Java JSch在远程机器上更改用户并执行命令

使用Java JSch可以在远程机器上切换用户并执行命令，具体步骤如下：

1. 创建JSch实例

JSch jsch = new JSch();

2. 连接到远程服务器

Session session = jsch.getSession(username, host, port);
session.setPassword(password);
session.connect();

3. 切换用户

ChannelExec channel = (ChannelExec) session.openChannel("exec");
channel.setCommand("sudo -u newuser bash");
channel.connect();

4. 执行命令

channel = (ChannelExec) session.openChannel("exec");
channel.setCommand("ls -l");
channel.connect();
InputStream in = channel.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = reader.readLine()) != null) {
    System.out.println(line);
}
channel.disconnect();

5. 关闭连接

session.disconnect();

需要注意的是，在切换用户时需要输入新用户的密码，可以使用`channel.setPty(true)`来开启一个伪终端，从而可以输入密码。

完整代码示例：

import com.jcraft.jsch.*;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

public class JSchDemo {
    public static void main(String[] args) {
        String host = "remote_host";
        int port = 22;
        String username = "olduser";
        String password = "oldpassword";
        try {
            JSch jsch = new JSch();
            Session session = jsch.getSession(username, host, port);
            session.setPassword(password);
            session.connect();
            ChannelExec channel = (ChannelExec) session.openChannel("exec");
            channel.setCommand("sudo -u newuser bash");
            channel.connect();
            channel = (ChannelExec) session.openChannel("exec");
            channel.setCommand("ls -l");
            channel.connect();
            InputStream in = channel.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
            channel.disconnect();
            session.disconnect();
        } catch (JSchException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}