在Java中通过SSH隧道连接Mongo数据库

Question

修复（编辑代码以反映我所做的更改）

我正在尝试使用Java通过SSH隧道连接到Mongo数据库。

我正在使用Mongo驱动程序3.0.2和jcraft（JSch）创建一个SSH隧道。我的想法是：

• 通过SSH连接到托管MongoDB安装的机器
• 设置从本地端口到远程MongoDB端口的端口转发
• 远程连接到MongoDB

我的代码如下所示：

// forwarding ports
private static final String LOCAL_HOST = "localhost";
private static final String REMOTE_HOST = "127.0.0.1";
private static final Integer LOCAL_PORT = 8988;
private static final Integer REMOTE_PORT = 27017; // Default mongodb port

// ssh connection info
private static final String SSH_USER = "<username>";
private static final String SSH_PASSWORD = "<password>";
private static final String SSH_HOST = "<remote host>";
private static final Integer SSH_PORT = 22;

private static Session sshSession;

public static void main(String[] args) {
try {
    java.util.Properties config = new java.util.Properties();
    config.put("StrictHostKeyChecking", "no");
    JSch jsch = new JSch();
    sshSession = null;
    sshSession = jsch.getSession(SSH_USER, SSH_HOST, SSH_PORT);
    sshSession.setPassword(SSH_PASSWORD);
    sshSession.setConfig(config);
    sshSession.connect();
    sshSession.setPortForwardingL(LOCAL_PORT, REMOTE_HOST, REMOTE_PORT);

    MongoClient mongoClient = new MongoClient(LOCAL_HOST, LOCAL_PORT);
    mongoClient.setReadPreference(ReadPreference.nearest());
    MongoCursor<String> dbNames = mongoClient.listDatabaseNames().iterator();
    while (dbNames.hasNext()) {
    System.out.println(dbNames.next());
    }
} catch (Exception e) {
    e.printStackTrace();
} finally {
    sshSession.delPortForwardingL(LOCAL_PORT);
    sshSession.disconnect();
}
}

这段代码在运行时， 不 EDIT:有效。 连接到SSH服务器工作正常，但连接到其背后的Mongo数据库不起作用，并返回以下错误：

INFO: Exception in monitor thread while connecting to server localhost:8988
com.mongodb.MongoSocketReadException: Prematurely reached end of stream
    at com.mongodb.connection.SocketStream.read(SocketStream.java:88)
    at com.mongodb.connection.InternalStreamConnection.receiveResponseBuffers(InternalStreamConnection.java:491)
    at com.mongodb.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:221)
    at com.mongodb.connection.CommandHelper.receiveReply(CommandHelper.java:134)
    at com.mongodb.connection.CommandHelper.receiveCommandResult(CommandHelper.java:121)
    at com.mongodb.connection.CommandHelper.executeCommand(CommandHelper.java:32)
    at com.mongodb.connection.InternalStreamConnectionInitializer.initializeConnectionDescription(InternalStreamConnectionInitializer.java:83)
    at com.mongodb.connection.InternalStreamConnectionInitializer.initialize(InternalStreamConnectionInitializer.java:43)
    at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:115)
    at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:127)
    at java.lang.Thread.run(Unknown Source)

我试着通过命令行这样做，如下所示：

$ ssh <user>@<host> -p 22 -X -C
$ <enter requested password>
<user>@<host>$ mongo
<user>@<host>$ MongoDB shell version: 2.6.10
<user>@<host>$ connecting to: test

所以这似乎奏效了。我不明白为什么Java代码（应该做大致相同的事情）不起作用。

Answer 1

此代码已成功运行，但主要问题是您的mongo db已停止。请检查mongo的实例是否正在运行。

sudo systemctl status mongod

如果它没有运行

sudo systemctl start mongod

Answer 2

我设法让它工作（尝试将端口转发到“localhost”而不是“127.0.0.1”，并对其进行了修改）编辑：我猜服务器是专门在localhost而不是127.0.0.1上监听的