java实现的telnet协议

package telnet;

 

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.Socket;

import java.util.ArrayList;

import java.util.List;

 

 

/**

 * Telnet简单实现

 * 

 * @author xueliang 2010.11.6

 * 

 */

public class Telnet {

private static final byte SB = (byte) 250;// 子选项开始

private static final byte SE = (byte) 240;// 子选项结束

private static final byte WILL = (byte) 251;// 选项协商

private static final byte WONT = (byte) 252;// 选项协商

private static final byte DO = (byte) 253;// 选项协商

private static final byte DONT = (byte) 254;// 选项协商

private static final byte IAC = (byte) 255;// 数据字节255

private static final byte ECHO = (byte) 1;// 回显

private static final byte IS = (byte) 0;// 是

private static final byte SUPPRESS = (byte) 3;// 抑制继续进行

private static final byte TT = (byte) 24;// 终端类型

private InputStream is;

private OutputStream os;

private Socket client;

private byte[] readBuffer = new byte[1024];

 

/**

* 打开telnet连接

* @param ip

* @param port 23

* @return

* @throws CmdException 

*/

public Telnet(String ip){

this(ip, 23);

}

 

/**

* 打开telnet连接

* @param ip

* @param port

* @return

* @throws CmdException 

*/

public Telnet(String ip, int port){

try {

client = new Socket(ip, port);

client.setSoTimeout(5000);//设置is的read方法阻塞时间为5秒

is = client.getInputStream();

os = client.getOutputStream();

} catch (Exception e) {

this.close();

} 

}

/**

* 读取回显，并进行telnet协商

* @return

* @throws IOException

*/

public String recieveEcho() throws IOException {

int len = is.read(this.readBuffer);

if(is.available() == 0)

return "";

ArrayList<Byte> bsList = new ArrayList<Byte>();

ArrayList<Byte> cmdList = new ArrayList<Byte>();

for (int i = 0; i < len; i++) {

int b = this.readBuffer[i] & 0xff;//&0xff是为了防止byte的255溢出,java中byte的取值是-128~127

if (b != 255) {

if (b == '\n' || b == '\0') {// NVT中行结束符以'\r\n'表示，回车以'\r\0表示'

continue;

}

bsList.add((byte) b);

continue;

}

cmdList.add(IAC);

switch (this.readBuffer[++i] & 0xff) {

case 251:// 服务器想激活某选项

if ((readBuffer[++i] & 0xff) == 1) {// 同意回显

cmdList.add(DO);

cmdList.add(ECHO);

} else if ((readBuffer[i] & 0xff) == 3) {// 同意抑制继续执行

cmdList.add(DO);

cmdList.add(SUPPRESS);

// cmdList.add(GA);

} else {// 不同意其他类型协商

cmdList.add(DONT);

cmdList.add(readBuffer[i]);

}

break;

case 253:// 服务器想让客户端发起激活某选项

if ((readBuffer[++i] & 0xff) == 24) {// 终端类型

cmdList.add(WONT);// 同意激活终端类型协商

cmdList.add(TT);

} else if ((readBuffer[i] & 0xff) == 1) {

cmdList.add(WILL);

cmdList.add(ECHO);

} else {

cmdList.add(WONT);// 不同意其他类型协商

cmdList.add(readBuffer[i]);

}

break;

case 250:// 子选项开始

cmdList.add(SB);

if ((readBuffer[++i] & 0xff) == 24

&& (readBuffer[++i] & 0xff) == 1) {// 发送你的终端类型

cmdList.add(TT);

cmdList.add(IS);// 我的终端类型是

cmdList.add((byte) 'V');

cmdList.add((byte) 'T');

cmdList.add((byte) '1');

cmdList.add((byte) '0');

cmdList.add((byte) '0');

}

break;

case 240:// 子选项结束

cmdList.add(SE);

break;

case 252:// 必须同意

cmdList.add(DONT);

cmdList.add(readBuffer[++i]);

break;

case 254:// 必须同意

cmdList.add(WONT);

cmdList.add(readBuffer[++i]);

break;

}

}

// 如果有协商则向服务端发送协商选项

if (cmdList.size() > 0) {

byte[] writeBuffer = new byte[cmdList.size()];

for (int i = 0; i < cmdList.size(); i++) {

writeBuffer[i] = cmdList.get(i);

}

os.write(writeBuffer);

}

// 组织回显字符

int size = bsList.size();

String str = "";

if (size > 0) {

byte[] bs = new byte[size];

for (int i = 0; i < size; i++) {

bs[i] = bsList.get(i).byteValue();

}

str = new String(bs, "gbk");

}

// 以下测试时打开

// System.out.print("read===== ");

// for (int i = 0; i < len; i++) {

// System.out.print(readBuffer[i]&0xff);

// System.out.print(" ");

// }

// System.out.println();

// if(cmdList.size()>0){

// System.out.print("write==== ");

// for (int i = 0; i < cmdList.size(); i++) {

// System.out.print(cmdList.get(i) & 0xff);

// System.out.print(" ");

// }

// System.out.println();

// }

return str;

}

 

/**

* 直接发送命令，不发送回车键

* @param cmd

*/

public void sendWithoutCR(String cmd) {

try {

os.write(cmd.getBytes());

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* 命令中不要包括回车、换行

* @param cmd

*/

public void sendCmd(String cmd) {

cmd += "\r\0";

try {

os.write(cmd.getBytes());

} catch (IOException e) {

e.printStackTrace();

}

}

 

/**

* 按字节发送命令，数组中不要包括回车、换行

* @param cmd

*/

public void sendCmd(List<Byte> cmdList) {

if(cmdList == null)return;

int size = cmdList.size();

byte[] send = null;

if(cmdList.get(size-1) == '\r'){

send = new byte[size+1];

send[size] = '\0';

}else{

send = new byte[size];

}

for (int i = 0; i < size; i++) {

send[i] = cmdList.get(i);

}

try {

os.write(send);

} catch (IOException e) {

e.printStackTrace();

}

}

 

/**

* 关闭telnet连接

*/

public void close() {

if (is != null) {

try {

is.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if (os != null) {

try {

os.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if (client != null) {

try {

client.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

/**

* 读取期望值，使用默认超时时间15秒

* @param keyWords

* @return

*/

public String readKeyWords(String... keyWords){

return this.readKeyWords(15000, keyWords);

}

/**

* 读取期望值

* @param timeOut 超时时间

* @param keyWords

* @return

* @throws CmdException 

*/

public String readKeyWords(long timeOut,String... keyWords){

String rv = "";

long nextTime = 0;

long endTime = System.currentTimeMillis() + timeOut;

do {

try{

String _rv = this.recieveEcho();

rv += _rv;

}catch(IOException e){

nextTime = endTime - System.currentTimeMillis() ;

}

} while (!this.findKeyWord(keyWords, rv) && nextTime >= 0);

if(nextTime < 0)

System.err.println("Read TimeOut...Echo:\n"+rv);

return rv;

}

/**

* 查找关键字

* @param keyWords

* @param str

* @return

*/

private boolean findKeyWord(String[] keyWords,String str){

if(keyWords == null || str == null)return false;

for (int i = 0; i < keyWords.length; i++) {

if(str.indexOf(keyWords[i]) != -1)

return true;

}

return false;

}

public static void main(String[] args) {

Telnet telnet = new Telnet("10.110.111.193");

String str = telnet.readKeyWords(":");

System.out.println(str);

telnet.sendCmd("boco");

str = telnet.readKeyWords(":");

telnet.sendCmd("Ab123456");

str = telnet.readKeyWords("$");

System.out.println(str);

telnet.sendCmd("ls");

str = telnet.readKeyWords(10000,"$");

System.out.println(str);

telnet.close();

}

}