使用应用程序中的JSch连接到SFTP服务器时发生AccessControlException

Question

该小程序将从SFTP服务器下载文件。 JSch库用于创建会话，使用它连接到SFTP服务器，创建SFTP通道并对该服务器上的该文件执行GET命令。小程序已签名。

用于下载文件的代码片段：

public static void prepareSession() throws JSchException { 

    try { 
    session = jsch.getSession(user,host,port); 
    session.setConfig("StrictHostKeyChecking", "no");   
     session.setPassword(password); 
    } catch (JSchException e) { 
    e.printStackTrace(); 
    throw new JSchException(e.getLocalizedMessage(),e); 
    } 
} 

public synchronized static void downloadFile() throws Exception { 
    ChannelSftp channelSFTP = null; 
    try { 
    if (!session.isConnected()) { 
    session.connect(); 
    } 
    Channel channel=session.openChannel("sftp"); 
     channel.connect(); 
     channelSFTP=(ChannelSftp)channel; 

     String destFile = SFTPImpl.destFolder + "/" + SFTPImpl.sourceFile + ".part"; 

     log.info("Downloading file: " + SFTPImpl.sourceFile + " -- START"); 
     channelSFTP.get(SFTPImpl.sourceFile,destFile,SFTPImpl.monitor,ChannelSftp.OVERWRITE);  

    } catch (JSchException e) { 
    log.error("Error occurred within library", e); 
    throw new JSchException(e.getMessage(),e); 
    } catch (SftpException e) { 
    log.error("Error occurred in SFTP communication. Error ID: " + e.id, e); 
    throw new SftpException(e.id,e.getMessage(),e); 
    } catch (Exception e) { 
    throw new Exception(e.getMessage(),e); 
    }finally { 
    if (channelSFTP != null && channelSFTP.isConnected()) { 
    channelSFTP.quit(); 
     channelSFTP.disconnect(); 
     session.disconnect(); 
    } 
    } 
} 

applet是使用Java部署工具包部署。对于小应用程序部署HTML页面的代码片段是：

<script src="http://www.java.com/js/deployJava.js"></script> 
    <script> 
    var attributes = {code:'com.sftptest.applet.SFTPApplet', archive:'signedsftp.jar,jsch.jar,log4j-1.2.15.jar', width:400, height:400} ; 
     var parameters = {jnlp_href: 'sftpdownload-applet.jnlp'} ; 
     deployJava.runApplet(attributes, parameters, '1.6'); 
    </script> 

sftpdownload-applet.jnlp文件：

<?xml version="1.0" encoding="UTF-8"?> 
<jnlp spec="1.0+" codebase="" href=""> 
    <information> 
     <title>SFTP Downloader</title> 
     <vendor>local</vendor> 
    </information> 
    <resources> 
     <!-- Application Resources --> 
     <j2se version="1.6+" 
       href="http://java.sun.com/products/autodl/j2se" /> 
     <jar href="signedsftpsftp.jar" main="true" /> 
     <jar href="jsch.jar" /> 
     <jar href="log4j-1.2.15.jar" /> 
    </resources> 
    <applet-desc 
     name="SFTP Downloader Applet" 
     main-class="com.sftptest.applet.SFTPApplet" 
     width="400" 
     height="400"> 
    </applet-desc> 
    <update check="background"/> 
</jnlp> 

小程序包含用来选择下载位置的文件选择器。只要选择了下载位置，小程序就应该开始下载文件。但一段时间后，下面的错误在控制台来：

[Oct 12 20:39:16] ERROR (SFTPImpl.java:130) - Error occurred within library 
com.jcraft.jsch.JSchException: java.security.AccessControlException: access denied (java.net.SocketPermission sftpcal.cognizant.com resolve) 
at com.jcraft.jsch.Util.createSocket(Util.java:341) 
at com.jcraft.jsch.Session.connect(Session.java:182) 
at com.jcraft.jsch.Session.connect(Session.java:150) 
at com.sftptest.SFTPImpl.downloadFile(SFTPImpl.java:111) 
at com.sftptest.ui.DownloadPanel$DownloadTask.doInBackground(DownloadPanel.java:316) 
at com.sftptest.ui.DownloadPanel$DownloadTask.doInBackground(DownloadPanel.java:1) 
at javax.swing.SwingWorker$1.call(SwingWorker.java:278) 
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) 
at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
at javax.swing.SwingWorker.run(SwingWorker.java:317) 
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) 
at java.lang.Thread.run(Thread.java:637) 

从异常日志我看到异常从JSch框架的Util.createSocket()方法来：

static Socket createSocket(String host, int port, int timeout) throws JSchException{ 
    Socket socket=null; 
    if(timeout==0){ 
     try{ 
     socket=new Socket(host, port); 
     return socket; 
     } 
     catch(Exception e){ 
     String message=e.toString(); 
     if(e instanceof Throwable) 
      throw new JSchException(message, (Throwable)e); 
     throw new JSchException(message); 
     } 
    } 

请帮&让我知道如果需要更多信息。

Answer 1

您已经签署的小程序，是的，但你忘了请求在您的JNLP插座创建权限。

<security> 
    <j2ee-application-client-permissions/> 
</security>