Java调用Telnet示例

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.io.UnsupportedEncodingException;

import org.apache.commons.net.telnet.TelnetClient;

/**
 * Telnet操作器,基于commons-net-2.2.jar
 * @author JiangKunpeng
 *
 */
public class TelnetOperator {

	private String prompt = ">";	//结束标识字符串,Windows中是>,Linux中是#
	private char promptChar = '>';	//结束标识字符
	private TelnetClient telnet;
	private InputStream in;		// 输入流,接收返回信息
	private PrintStream out;	// 向服务器写入 命令

	/**
	 * @param termtype	协议类型：VT100、VT52、VT220、VTNT、ANSI
	 * @param prompt	结果结束标识
	 */
	public TelnetOperator(String termtype,String prompt){
		telnet = new TelnetClient(termtype);
		setPrompt(prompt);
	}

	public TelnetOperator(String termtype){
		telnet = new TelnetClient(termtype);
	}

	public TelnetOperator(){
		telnet = new TelnetClient();
	}

	/**
	 * 登录到目标主机
	 * @param ip
	 * @param port
	 * @param username
	 * @param password
	 */
	public void login(String ip, int port, String username, String password){
		try {
			telnet.connect(ip, port);
			in = telnet.getInputStream();
			out = new PrintStream(telnet.getOutputStream());
			readUntil("login:");
			write(username);
			readUntil("password:");
			write(password);
			String rs = readUntil(null);
			if(rs!=null&&rs.contains("Login Failed")){
				throw new RuntimeException("登录失败");
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * 读取分析结果
	 *
	 * @param pattern	匹配到该字符串时返回结果
	 * @return
	 */
	public String readUntil(String pattern) {
		StringBuffer sb = new StringBuffer();
		try {
			char lastChar = (char)-1;
			boolean flag = pattern!=null&&pattern.length()>0;
			if(flag)
				lastChar = pattern.charAt(pattern.length() - 1);
			char ch;
			int code = -1;
			while ((code = in.read()) != -1) {
				ch = (char)code;
				sb.append(ch);

				//匹配到结束标识时返回结果
				if (flag) {
					if (ch == lastChar && sb.toString().endsWith(pattern)) {
						return sb.toString();
					}
				}else{
					//如果没指定结束标识,匹配到默认结束标识字符时返回结果
					if(ch == promptChar)
						return sb.toString();
				}
				//登录失败时返回结果
				if(sb.toString().contains("Login Failed")){
					return sb.toString();
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return sb.toString();
	}

	/**
	 * 发送命令
	 *
	 * @param value
	 */
	public void write(String value) {
		try {
			out.println(value);
			out.flush();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * 发送命令,返回执行结果
	 *
	 * @param command
	 * @return
	 */
	public String sendCommand(String command) {
		try {
			write(command);
			return readUntil(prompt);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 关闭连接
	 */
	public void distinct(){
		try {
			if(telnet!=null&&!telnet.isConnected())
				telnet.disconnect();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public void setPrompt(String prompt) {
		if(prompt!=null){
			this.prompt = prompt;
			this.promptChar = prompt.charAt(prompt.length()-1);
		}
	}

	public static void main(String[] args) {
		TelnetOperator telnet = new TelnetOperator("VT220",">");	//Windows,用VT220,否则会乱码
		telnet.login("192.168.2.19", 23, "administrator", "123456");
		String rs = telnet.sendCommand("ipconfig");
		try {
			rs = new String(rs.getBytes("ISO-8859-1"),"GBK");	//转一下编码
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		System.out.println(rs);
	}

}