【发布时间】：2018-05-05 21:57:08
【问题描述】：
多年来，我一直使用 JSch 连接到 Cisco 交换机。今天，我尝试以与交换机相同的方式连接到 Cisco WLC。没有任何效果！
异常：com.jcraft.jsch.JSchException：java.lang.NullPointerException
WLC 和交换机之间的区别在于，如果您首先尝试在 WLC 中使用 PuTTY 登录，WLC 会要求“登录为：”。在这里你可以写 fooBar 或者什么都不写。之后，WLC 要求输入用户名和密码！ 这是我使用的代码：
java.util.Properties configuration = new java.util.Properties();
configuration.put("kex", "diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256");
configuration.put("StrictHostKeyChecking", "no");
final JSch jsch = new JSch();
final Session session = jsch.getSession(TELNET_USER, outletWLC.getIp(),22);
session.setPassword(TELNET_PASSWORD);
session.setConfig(configuration);
session.connect(); // Here I get the Exception!
if (!session.isConnected()) {
throw new RuntimeException("cannot connect session");
}
final ChannelShell channelShell = (ChannelShell) session.openChannel("shell");
final ByteArrayInputStream toSwitchStream =
new ByteArrayInputStream(commandString.getBytes());
final ByteArrayOutputStream fromSwitchStream = new ByteArrayOutputStream();
final int available = toSwitchStream.available();
channelShell.setInputStream(toSwitchStream);
channelShell.setOutputStream(fromSwitchStream);
channelShell.connect();
周围有人解决了这个问题吗？
com.jcraft.jsch.JSchException: java.lang.NullPointerException
at com.jcraft.jsch.Session.receive_kexinit(Session.java:544)
at com.jcraft.jsch.Session.connect(Session.java:291)
at com.jcraft.jsch.Session.connect(Session.java:154)
at de.mediamarkt.indira.server.services.MSVorfPasswServiceImpl.readWLC(MSVorfPasswServiceImpl.java:169)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at de.mediamarkt.indira.server.remote.IndiraProxyServlet.service(IndiraProxyServlet.java:93)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1097)
at de.mediamarkt.indira.server.filter.IndiraMultiPersistenceUnitTransactionFilter.doFilter(IndiraMultiPersistenceUnitTransactionFilter.java:23)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1088)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
at org.mortbay.jetty.handler.HandlerList.handle(HandlerList.java:49)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: java.lang.NullPointerException
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at com.jcraft.jsch.Session.receive_kexinit(Session.java:540)
... 26 more
JSch 日志：
INFO: Connecting to 10.3.xxx.xxx port 22
INFO: Connection established
INFO: Remote version string: SSH-2.0-CISCO_WLC
INFO: Local version string: SSH-2.0-JSCH-0.1.44
INFO: CheckCiphers: aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,3des-ctr,arcfour,arcfour128,arcfour256
INFO: aes256-ctr is not available.
INFO: aes192-ctr is not available.
INFO: aes256-cbc is not available.
INFO: aes192-cbc is not available.
INFO: arcfour256 is not available.
INFO: SSH_MSG_KEXINIT sent
INFO: SSH_MSG_KEXINIT received
INFO: kex: server->client aes128-ctr hmac-sha1 none
INFO: kex: client->server aes128-ctr hmac-sha1 none
INFO: Disconnecting from 10.3.xxx.xxx port 22
【问题讨论】：
-
com.jcraft.jsch.JSchException: java.lang.NullPointerException
-
该行最终Session session = jsch.getSession(System.lineSeparator()+TELNET_USER, outletWLC.getIp(),22);是为了测试，右边是final Session session = jsch.getSession(TELNET_USER, outletWLC.getIp(),22);
-
包含一个异常调用栈！并删除过时的 cmets。
-
您似乎没有使用最新版本的 JSch。你用的是哪一个？请升级到 0.1.54。
-
我用的是最新版！版本 = "0.1.54";