I have a doubt about Class Not Found Exception. I've added all the jars in my file but I cant seem to make it work. I've added the mysql-connector.jar in my project. DOes anyone know how to make it right?
try {
String driverName = "com.mysql.jdbc.Driver";
Class.forName(driverName);
String serverName = "localhost";
String mydatabase = "UFRJSocial";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
String username = "root";
String password = "";
connection = DriverManager.getConnection(url, username, password);
if (connection != null) {
status = ("STATUS--->Connected!");
} else {
status = ("STATUS--->The connection failed");
}
return connection;
} catch (ClassNotFoundException e) {
System.out.println("The specified driver was nor found");
//THIS IS THE LINE THAT MY CONSOLE IS SHOWING
return null;
} catch (SQLException e) {
System.out.println("it was not possible to connect to the database.");
return null;
}
Take a look at this code please:
enter code
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import app.dao.connector.DatabaseManager;
public class MySQLDatabaseManager implements DatabaseManager{
#Override
public Connection getConnection() {
final String USER_NAME ="root";
final String PASSWORD = "1234";
final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
final String JDBC_URL = "jdbc:mysql://localhost:3306/inventory system";
Connection conn = null;
try{
Class.forName(JDBC_DRIVER);
conn = DriverManager.getConnection(JDBC_URL, USER_NAME, PASSWORD);
}catch(ClassNotFoundException e){
e.printStackTrace();
}catch(SQLException e){
e.printStackTrace();
}
return conn;
}
As You can see, I tried to declare all my variables outside the try and catch block. In declaring the JDBC_URL specify your database.
I've managed to make it work. It was missing the mysql.jar file in the Web-INF folder.
Related
I am using Android Studio to make program.I tried to connect to database of SQL Server 2014. But I found net.sourceforge.jtds.jdbc.Driver error. I do not know where I was missing or wrong
This is my code
private static final String LOG = "DEBUG";
private static String ip = "192.168.3.85";
private static String port = "1434";
private static String Driver = "net.sourceforge.jtds.jdbc.Driver";
private static String db = "Work";
private static String un = "zom";
private static String password = "111111";
public void connect() {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
String ConnURL = null;
String query;
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
try {
Class.forName(Driver);
ConnURL = "jdbc:jtds:sqlserver://" + ip +":"+port+";"
+ "databaseName=" + db + ";user=" + un + ";password="
+ password + ";";
query=" SELECT [Production order] FROM TIMEDATA1 WHERE RecordID = (SELECT MAX (RECORDID ) FROM TIMEDATA1 WHERE [Resource] = ? )";
conn = DriverManager.getConnection(ConnURL);
stmt=conn.prepareStatement(query);
stmt.setString(1,"M-MP3");
rs = stmt.executeQuery();
while (rs.next()) {
String result = rs.getString(1);
mTextMessage.setText(result);
Log.d("My Custom Tag", result);
}
rs.close();
stmt.close();
} catch (SQLException e) {
Log.d("Error 1", e.getMessage());
} catch (ClassNotFoundException e) {
Log.d("Error 2", e.getMessage());
}
}
How can I connect to remote MySQL database through SSH from java application? Small code example is helpful for me and I'd appreciate this.
My understanding is that you want to access a mysql server running on a remote machine and listening on let's say port 3306 through a SSH tunnel.
To create such a tunnel from port 1234 on your local machine to port 3306 on a remote machine using the command line ssh client, you would type the following command from your local machine:
ssh -L 1234:localhost:3306 mysql.server.remote
To do the same thing from Java, you could use JSch, a Java implementation of SSH2. From its website:
JSch allows you to connect to an sshd server and use port forwarding, X11 forwarding, file transfer, etc., and you can integrate its functionality into your own Java programs. JSch is licensed under BSD style license.
For an example, have a look at PortForwardingL.java. Once the session connected, create your JDBC connection to MySQL using something like jdbc:mysql://localhost:1234/[database] as connection URL.
My detail code is below:
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 = 'ripon.wasim#smile.com' WHERE email='peace#happy.com'";
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();
}
}
}
While the existing answers are correct, they obscure the significant code in bloats of other code.
This is the basic code you need to tunnel your JDBC (or any other) database connection through an SSH channel:
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);
You will also have to deal with host key verification. For that see:
How to resolve Java UnknownHostKey, while using JSch SFTP library?
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();
}
}
}
First of all, thank you works great!
Though, I wonder if I should reuse that Session for every (potentially simultaneous) SQL Connection, or if I should create a new Session every time and only refresh it if for some reason it has expired.
Currently, I would every time I make a connection make a new instance of that Controller here and then do the SQL queries with the connection I got from it, then close it manually.
Would also be nice if I could make the class useable with try-with-resource and it closing itself. Will look into that. Cause I don´t wanna miss closing it.
That´s how the thing looks like, I'm getting DB Connections from right now.
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();
}
}
If you wonder DbSettingsController I´ve made myself too, just puts settings in a Text column in a local SQLite DB, with a key assigned to it (that enum´s int value). Was just copy paste code I reused from some other project, so it was simple and fast to just do that this way.
I have this problem when I try to connect to my MySQL database. It gives me out that it's wrong and I don't know why because it doesn't give me a specific error.
It just gives me out what I wrote in the catch.
BTW I'm using MySQL Connector/J Version 5.1.47.
This is the connection Code:
private class GetData extends AsyncTask<String,String,String> {
String msg = "";
//JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://" +
DbStrings.DATABASE_URL + "/" +
DbStrings.DATABASE_NAME;
#Override
protected void onPreExecute() {
ProgressTextView.setText("Connecting to Database...");
}
#Override
protected String doInBackground(String... params) {
Connection conn = null;
Statement stmt = null;
try {
Class.forName(JDBC_DRIVER);
conn = DriverManager.getConnection(DB_URL, DbStrings.USERNAME, DbStrings.PASSWORD);
stmt = conn.createStatement();
String sql = "SELECT * FROM zimmerstamm";
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
String Bemerkung = rs.getString("Bemerkung");
Double Zimmer = rs.getDouble("Zimmer");
fruitsMap.put(Bemerkung, Zimmer);
}
msg = "Process complete";
rs.close();
stmt.close();
conn.close();
} catch (SQLException connError) {
msg = "An exception was thrwon for JDBC.";
connError.printStackTrace();
} catch (ClassNotFoundException e) {
msg = "And exception was No class found.";
e.printStackTrace();
}
I have poor knowledge about programming. I need to save image in MySQL database. I have created a database table and there is a column to add image with longblob data type.
I have code to a button to choose image from folder in PC then it load to a jlable. Now I need to insert this image to a database.
This is my code;
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser fc=new JFileChooser();
fc.showOpenDialog(this);
File f=fc.getSelectedFile();
String path=f.getAbsolutePath();
jLabel1.setIcon(new ImageIcon(path));
try{
FileInputStream fin=new FileInputStream(f);
int len=(int)f.length(); Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost/hss", "root", "bis123");
PreparedStatement ps=con.prepareStatement("Insert into profile values(?)");
ps.setBinaryStream(1, fin, len);
int status=ps.executeUpdate();
if(status > 0) {
jLabel2.setText("Successfully inserted in DB");
}else{
jLabel2.setText("Image not inserted!");
}
}catch(Exception e){
System.out.println(e);
}
}
In MySQL when we use the blob type to store the data , it support only 5 kb image capacity.
CREATE TABLE image (
id varchar(45) DEFAULT NULL,
size int(11) DEFAULT NULL,
image longblob
);
created database table in above code
this is java code to insert image in database
import java.sql.*;
import java.io.*;
public class InsertImagesMysql{
public static void main(String[] args){
System.out.println("Insert Image Example!");
String driverName = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/";
String dbName = "test";
String userName = "root";
String password = "root";
Connection con = null;
try{
Class.forName(driverName);
con = DriverManager.getConnection(url+dbName,userName,password);
Statement st = con.createStatement();
File imgfile = new File("pic.jpg");
FileInputStream fin = new FileInputStream(imgfile);
PreparedStatement pre =
con.prepareStatement("insert into Image values(?,?,?)");
pre.setString(1,"test");
pre.setInt(2,3);
pre.setBinaryStream(3,(InputStream)fin,(int)imgfile.length());
pre.executeUpdate();
System.out.println("Successfully inserted the file into the database!");
pre.close();
con.close();
}catch (Exception e1){
System.out.println(e1.getMessage());
}
}
}
here is code to retrieve data from database
import java.io.*;
import java.sql.*;
public class RetriveImagesMysql{
public static void main(String[] args){
System.out.println("Retrive Image Example!");
String driverName = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/";
String dbName = "test";
String userName = "root";
String password = "root";
Connection con = null;
try{
Class.forName(driverName);
con = DriverManager.getConnection(url+dbName,userName,password);
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select image from image");
int i = 0;
while (rs.next()) {
InputStream in = rs.getBinaryStream(1);
OutputStream f = new FileOutputStream(new File("test"+i+".jpg"));
i++;
int c = 0;
while ((c = in.read()) > -1) {
f.write(c);
}
f.close();
in.close();
}
}catch(Exception ex){
System.out.println(ex.getMessage());
}
}
}
here just assign fin to jbutton action event it will trigger automatically the run of the code
How can I connect to remote MySQL database through SSH from java application? Small code example is helpful for me and I'd appreciate this.
My understanding is that you want to access a mysql server running on a remote machine and listening on let's say port 3306 through a SSH tunnel.
To create such a tunnel from port 1234 on your local machine to port 3306 on a remote machine using the command line ssh client, you would type the following command from your local machine:
ssh -L 1234:localhost:3306 mysql.server.remote
To do the same thing from Java, you could use JSch, a Java implementation of SSH2. From its website:
JSch allows you to connect to an sshd server and use port forwarding, X11 forwarding, file transfer, etc., and you can integrate its functionality into your own Java programs. JSch is licensed under BSD style license.
For an example, have a look at PortForwardingL.java. Once the session connected, create your JDBC connection to MySQL using something like jdbc:mysql://localhost:1234/[database] as connection URL.
My detail code is below:
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 = 'ripon.wasim#smile.com' WHERE email='peace#happy.com'";
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();
}
}
}
While the existing answers are correct, they obscure the significant code in bloats of other code.
This is the basic code you need to tunnel your JDBC (or any other) database connection through an SSH channel:
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);
You will also have to deal with host key verification. For that see:
How to resolve Java UnknownHostKey, while using JSch SFTP library?
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();
}
}
}
First of all, thank you works great!
Though, I wonder if I should reuse that Session for every (potentially simultaneous) SQL Connection, or if I should create a new Session every time and only refresh it if for some reason it has expired.
Currently, I would every time I make a connection make a new instance of that Controller here and then do the SQL queries with the connection I got from it, then close it manually.
Would also be nice if I could make the class useable with try-with-resource and it closing itself. Will look into that. Cause I don´t wanna miss closing it.
That´s how the thing looks like, I'm getting DB Connections from right now.
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();
}
}
If you wonder DbSettingsController I´ve made myself too, just puts settings in a Text column in a local SQLite DB, with a key assigned to it (that enum´s int value). Was just copy paste code I reused from some other project, so it was simple and fast to just do that this way.