如何通过SSH从Java应用程序连接到远程MySQL数据库？小代码示例对我有帮助，我很欣赏这一点。
我的理解是你想要访问在远程机器上运行的mysql服务器并通过SSH隧道监听端口3306。
要使用命令行ssh client从本地计算机上的端口1234到远程计算机上的端口3306创建此类隧道，您可以从本地计算机键入以下命令：
ssh -L 1234:localhost:3306 mysql.server.remote
要从Java做同样的事情，你可以使用JSch，一个SSH2的Java实现。从其网站：
JSch允许您连接到sshd服务器并使用端口转发，X11转发，文件传输等，您可以将其功能集成到您自己的Java程序中。 JSch根据BSD风格许可证授权。
举个例子，看看PortForwardingL.java。连接会话后，使用jdbc:mysql://localhost:1234/[database]作为连接URL创建与MySQL的JDBC连接。
我的详细代码如下：
package mypackage;
import java.sql.*;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
public class UpdateMySqlDatabase {
static int lport;
static String rhost;
static int rport;
public static void go(){
String user = "ripon";
String password = "wasim";
String host = "myhost.ripon.wasim";
int port=22;
try
{
JSch jsch = new JSch();
Session session = jsch.getSession(user, host, port);
lport = 4321;
rhost = "localhost";
rport = 3306;
session.setPassword(password);
session.setConfig("StrictHostKeyChecking", "no");
System.out.println("Establishing Connection...");
session.connect();
int assinged_port=session.setPortForwardingL(lport, rhost, rport);
System.out.println("localhost:"+assinged_port+" -> "+rhost+":"+rport);
}
catch(Exception e){System.err.print(e);}
}
public static void main(String[] args) {
try{
go();
} catch(Exception ex){
ex.printStackTrace();
}
System.out.println("An example for updating a Row from Mysql Database!");
Connection con = null;
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://" + rhost +":" + lport + "/";
String db = "testDB";
String dbUser = "wasim";
String dbPasswd = "riponalwasim123";
try{
Class.forName(driver);
con = DriverManager.getConnection(url+db, dbUser, dbPasswd);
try{
Statement st = con.createStatement();
String sql = "UPDATE MyTableName " +
"SET email = '[email protected]' WHERE email='[email protected]'";
int update = st.executeUpdate(sql);
if(update >= 1){
System.out.println("Row is updated.");
}
else{
System.out.println("Row is not updated.");
}
}
catch (SQLException s){
System.out.println("SQL statement is not executed!");
}
}
catch (Exception e){
e.printStackTrace();
}
}
}
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
public class CTestDriver {
private static void doSshTunnel(String strSshUser, String strSshPassword, String strSshHost, int nSshPort,
String strRemoteHost, int nLocalPort, int nRemotePort) throws JSchException {
final JSch jsch = new JSch();
Session session = jsch.getSession(strSshUser, strSshHost, 22);
session.setPassword(strSshPassword);
final Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();
session.setPortForwardingL(nLocalPort, strRemoteHost, nRemotePort);
}
public static void main(String[] args) {
try {
String strSshUser = "ssh_user_name"; // SSH loging username
String strSshPassword = "abcd1234"; // SSH login password
String strSshHost = "your.ssh.hostname.com"; // hostname or ip or
// SSH server
int nSshPort = 22; // remote SSH host port number
String strRemoteHost = "your.database.hostname.com"; // hostname or
// ip of
// your
// database
// server
int nLocalPort = 3366; // local port number use to bind SSH tunnel
int nRemotePort = 3306; // remote port number of your database
String strDbUser = "db_user_name"; // database loging username
String strDbPassword = "4321dcba"; // database login password
CTestDriver.doSshTunnel(strSshUser, strSshPassword, strSshHost, nSshPort, strRemoteHost, nLocalPort,
nRemotePort);
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:" + nLocalPort, strDbUser,
strDbPassword);
con.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
System.exit(0);
}
}
}
package framework.restapi.utils;
import java.sql.*;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.sql.Connection;
import java.util.ArrayList;
import java.util.List;
public class SQLConnection {
private static Connection connection = null;
private static Session session = null;
private static void connectToServer(String dataBaseName) throws SQLException {
connectSSH();
connectToDataBase(dataBaseName);
}
private static void connectSSH() throws SQLException {
String sshHost = "";
String sshuser = "";
String dbuserName = "";
String dbpassword = "";
String SshKeyFilepath = "/Users/XXXXXX/.ssh/id_rsa";
int localPort = 8740; // any free port can be used
String remoteHost = "127.0.0.1";
int remotePort = 3306;
String localSSHUrl = "localhost";
/***************/
String driverName = "com.mysql.jdbc.Driver";
try {
java.util.Properties config = new java.util.Properties();
JSch jsch = new JSch();
session = jsch.getSession(sshuser, sshHost, 22);
jsch.addIdentity(SshKeyFilepath);
config.put("StrictHostKeyChecking", "no");
config.put("ConnectionAttempts", "3");
session.setConfig(config);
session.connect();
System.out.println("SSH Connected");
Class.forName(driverName).newInstance();
int assinged_port = session.setPortForwardingL(localPort, remoteHost, remotePort);
System.out.println("localhost:" + assinged_port + " -> " + remoteHost + ":" + remotePort);
System.out.println("Port Forwarded");
} catch (Exception e) {
e.printStackTrace();
}
}
private static void connectToDataBase(String dataBaseName) throws SQLException {
String dbuserName = "sf2_showpad_biz";
String dbpassword = "lOAWEnL3K";
int localPort = 8740; // any free port can be used
String localSSHUrl = "localhost";
try {
//mysql database connectivity
MysqlDataSource dataSource = new MysqlDataSource();
dataSource.setServerName(localSSHUrl);
dataSource.setPortNumber(localPort);
dataSource.setUser(dbuserName);
dataSource.setAllowMultiQueries(true);
dataSource.setPassword(dbpassword);
dataSource.setDatabaseName(dataBaseName);
connection = dataSource.getConnection();
System.out.print("Connection to server successful!:" + connection + "\n\n");
} catch (Exception e) {
e.printStackTrace();
}
}
private static void closeConnections() {
CloseDataBaseConnection();
CloseSSHConnection();
}
private static void CloseDataBaseConnection() {
try {
if (connection != null && !connection.isClosed()) {
System.out.println("Closing Database Connection");
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
private static void CloseSSHConnection() {
if (session != null && session.isConnected()) {
System.out.println("Closing SSH Connection");
session.disconnect();
}
}
// works ONLY FOR single query (one SELECT or one DELETE etc)
private static ResultSet executeMyQuery(String query, String dataBaseName) {
ResultSet resultSet = null;
try {
connectToServer(dataBaseName);
Statement stmt = connection.createStatement();
resultSet = stmt.executeQuery(query);
System.out.println("Database connection success");
} catch (SQLException e) {
e.printStackTrace();
}
return resultSet;
}
public static void DeleteOrganisationReferencesFromDB(String organisationsLike) {
try {
connectToServer("ServerName");
Statement stmt = connection.createStatement();
ResultSet resultSet = stmt.executeQuery("select * from DB1");
String organisationsToDelete = "";
List<String> organisationsIds = new ArrayList<String>();
// create string with id`s values to delete organisations references
while (resultSet.next()) {
String actualValue = resultSet.getString("id");
organisationsIds.add(actualValue);
}
for (int i = 0; i < organisationsIds.size(); i++) {
organisationsToDelete = " " + organisationsToDelete + organisationsIds.get(i);
if (i != organisationsIds.size() - 1) {
organisationsToDelete = organisationsToDelete + ", ";
}
}
stmt.executeUpdate(" DELETE FROM `DB1`.`table1` WHERE `DB1`.`table1`.`organisation_id` in ( " + organisationsToDelete + " );");
} catch (SQLException e) {
e.printStackTrace();
} finally {
closeConnections();
}
}
public static List<String> getOrganisationsDBNamesBySubdomain(String organisationsLike) {
List<String> organisationDbNames = new ArrayList<String>();
ResultSet resultSet = executeMyQuery("select `DB`.organisation.dbname from `DB1`.organisation where subdomain like '" + organisationsLike + "%'", "DB1");
try {
while (resultSet.next()) {
String actualValue = resultSet.getString("dbname");
organisationDbNames.add(actualValue);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
closeConnections();
}
return organisationDbNames;
}
public static List<String> getAllDBNames() {
// get all live db names incentral DB
List<String> organisationDbNames = new ArrayList<String>();
ResultSet resultSet = executeMyQuery("show databases", "DB1");
try {
while (resultSet.next()) {
String actualValue = resultSet.getString("Database");
organisationDbNames.add(actualValue);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
closeConnections();
}
return organisationDbNames;
}
public static void deleteDataBasesByName(List<String> DataBasesNamesList) {
try {
connectSSH();
int dataBasesAmount = DataBasesNamesList.size();
for (int i = 0; i < dataBasesAmount; i++) {
connectToDataBase(DataBasesNamesList.get(i));
Statement stmt = connection.createStatement();
stmt.executeUpdate("DROP database `" + DataBasesNamesList.get(i) + "`");
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
CloseDataBaseConnection();
closeConnections();
}
}
}
虽然现有的答案是正确的，但它们掩盖了其他代码膨胀的重要代码。
这是通过SSH通道隧道传输JDBC（或任何其他）数据库连接所需的基本代码：
String jumpserverHost = "ssh.example.com";
String jumpserverUsername = "sshuser";
// The hostname/IP address and port, you would use on the SSH server
// to connect to the database.
// If the database runs on the same machine as the SSH server, use "localhost".
String databaseHost = "database.example.com";
int databasePort = 3306;
String databaseUsername = "dbuser";
String databasePassword = "dbpass";
JSch jsch = new JSch();
// Public key authentication example
// (but you can use password authentication, if appropriate).
jsch.addIdentity("~/.ssh/id_rsa");
// Connect to SSH jump server (this does not show an authentication code)
Session session = jsch.getSession(jumpserverUsername, jumpserverHost);
session.connect();
// Forward randomly chosen local port through the SSH channel to database host/port
int forwardedPort = session.setPortForwardingL(0, databaseHost, databasePort);
// Connect to the forwarded port (the local end of the SSH tunnel)
// If you don't use JDBC, but another database client,
// just connect it to the localhost:forwardedPort
String url = "jdbc:mysql://localhost:" + forwardedPort;
Connection con = DriverManager.getConnection(url, databaseUsername, databasePassword);
您还必须处理主机密钥验证。为此，请参阅： How to resolve Java UnknownHostKey, while using JSch SFTP library?
首先，谢谢你的作品！
虽然，我想知道我是否应该为每个（可能同时的）SQL连接重用该Session，或者我是否应该每次都创建一个新的Session，并且只有在某些原因它已经过期时才刷新它。
目前，我每次建立连接时都会在此处创建该Controller的新实例，然后使用我从中获得的连接执行SQL查询，然后手动关闭它。
如果我可以通过try-with-resource使这个类可用并且它自己关闭也会很好。会调查一下。因为我不想错过关闭它。
这就是事情的样子，我现在正在接收DB Connections。
public class ConnectionManager {
private Connection con = null;
private Session session = null;
public Connection getConnection() {
Connection con = null;
var settings = new DbSettingsController();
boolean useSSH = settings.getSetting(SettingKey.UseSSH).equals("true");
String sshPort = settings.getSetting(SettingKey.SSHPort);
String sqlIp = settings.getSetting(SettingKey.MySqlIP);
String sqlPort = settings.getSetting(SettingKey.MySqlPort);
if(useSSH) {
JSch jSch = new JSch();
try {
this.session = jSch.getSession(settings.getSetting(SettingKey.SSHUser),
settings.getSetting(SettingKey.SSHHost),
Integer.valueOf(sshPort));
this.session.setPassword(settings.getSetting(SettingKey.SSHPassword));
this.session.setConfig("StrictHostKeyChecking", "no");
this.session.connect();
this.session.setPortForwardingL(Integer.parseInt(sshPort), sqlIp, Integer.parseInt(sqlPort));
} catch (JSchException e) {
e.printStackTrace();
}
}
var connectionString = String.format("jdbc:mysql://%s:%s/%s?autoReconnect=true&useSSL=false",
sqlIp, useSSH ? sshPort : sqlPort,
settings.getSetting(SettingKey.MySqlShema));
var user = settings.getSetting(SettingKey.MySqlUser);
var password = settings.getSetting(SettingKey.MySqlPassword);
try {
con = DriverManager.getConnection(connectionString, user, password);
} catch (SQLException e) {
e.printStackTrace();
}
return con;
}
public void close() {
if(this.con != null) {
try {
this.con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(this.session != null) {
this.session.disconnect();
}
}
如果你想知道DbSettingsController我自己也做了，只需将设置放在本地SQLite DB的Text列中，并为其分配一个键（即enum的int值）。只是复制粘贴代码我从其他项目中重复使用，所以这样做简单快捷。