So I´ve been struggling with the JDBC driver to get my MySQL database running in my Android application. It´s a simple application that I have to make for school but I keep getting NullPointers at the Connection class.
I tested the connection in a regular Java project in Netbeans and that works fine.
Here is my code:
private Connection conn;
public data_Administration dataAdministration = data_Administration.getInstance();
public data_SQL()
{
this.connectToDatabase();
}
protected void connectToDatabase()
{
try
{
try
{
Class.forName("com.mysql.jdbc.Driver");
}
catch(Exception ee)
{
}
}
catch(Exception eee)
{
}
try
{
conn = DriverManager.getConnection("jdbc:mysql://db4free.net:3306/", ****, ****);
}
catch (SQLException ex)
{
}
}
Related
package com.example.financecontrol;
import java.sql.*;
public class DBController {
public static Connection Connector() {
try {
Class.forName("org.sqlite.JDBC");
Connection conn = DriverManager.getConnection("jdbc:sqlite:FinanceControl.sqlite");
return conn;
} catch (Exception e) {
System.out.println(e);
return null;
}
}
}
Is there a way to initialise database with some data if it does not exist. The problem is that I want to add some tables and configs while launching the application for the first time?
What I needed is "CREATE TABLE IF NOT EXISTS" statement. It worked properly!
I'm trying to connect my Java code to a db I've created in Google Cloud SQL, but I'm getting ClassNotFound and SQLException errors: -
java.lang.ClassNotFoundException: com.google.cloud.sql.mysql.SocketFactory
java.sql.SQLException: No suitable driver found for jdbc:mysql
I'm also getting a NullPointerException in code, in the getAllFilms() method at the line below, which I'm assuming is because the code isn't making a db connection: -
ResultSet rs1 = stmt.executeQuery(selectSQL);
Things I've done so far: -
Tested the Google Cloud SQL db credentials, through a client connection
Reviewed related posts, particularly [this one][1]
Been through the Google documentation
Added MySQL and Socket Factory Connector(j8) JARs to my project dependencies
Unfortunately I'm still unable to resolve. Hopefully someone can help. I've attached my Java code below. Thanks in advance...
Film oneFilm = null;
Connection googleSqlConnection = null;
Statement stmt = null;
String url = "jdbc:mysql:///<dbname>?<cloudSqlInstance>&socketFactory=com.google.cloud.sql.
mysql.SocketFactory&user=<user>&password=<pword>";
public FilmDAO() {
}
private void openConnection() {
try {
Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.google.cloud.sql.mysql.SocketFactory");
} catch (Exception e) {
System.out.println(e);
}
try {
googleSqlConnection = DriverManager.getConnection(url);
stmt = googleSqlConnection.createStatement();
} catch (SQLException se) {
System.out.println(se);
}
}
private void closeConnection() {
try {
googleSqlConnection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public ArrayList<Film> getAllFilms() {
ArrayList<Film> allFilms = new ArrayList<>();
openConnection();
try {
String selectSQL = "select * from films limit 50";
ResultSet rs1 = stmt.executeQuery(selectSQL);
while (rs1.next()) {
oneFilm = getNextFilm(rs1);
allFilms.add(oneFilm);
}
stmt.close();
closeConnection();
} catch (SQLException se) {
System.out.println(se);
}
return allFilms;
}
[1]: https://stackoverflow.com/questions/53693679/connecting-to-google-cloud-sql-with-java
Have you added the Cloud SQL JDBC SocketFactory and mysql-connector-java to your pom.xml?
I wanted to connect DB to Java application in Intellij.
I set the classpath correctly, so that javac from cmd is working correct.
I have also downloaded all the jar files needed as a libary, but I still get java.sql.SQLException: No suitable driver found for jdbc:derby
What can be the problem?
public static void main(String[] args) {
try {
Class.forName("org.apache.derby.jdbc.ClientDriver");
} catch(java.lang.ClassNotFoundException e) {
e.printStackTrace();
}
final String DATABASE_URL = "jdbc:derby:myDB;create=true;user=user;password=pass";
try (
Connection connection = DriverManager.getConnection(DATABASE_URL, "user", "pass");
)
{
// ...
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
}
}
You can try if org.apache.derby.jdbc.EmbeddedDriver works. And it seems your connection url is wrong.
final String DATABASE_URL = "jdbc:derby://localhost:1527/myDB;create=true;user=user;password=pass";
Connection connection = null;
try{
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
connection = DriverManager.getConnection(DATABASE_URL );
}
catch (Exception e)
{
e.printStackTrace();
}
I have a problem with JDBC drivers. I can't connect with my SQL Server database. Following code for test:
public class Test {
public static void main(String[] args) {
Connection con = null;
String conUrl = "jdbc:sqlserver://localhost:1433; databaseName=mydb; user=root; password=psswd;";
try {
con = DriverManager.getConnection(conUrl);
System.out.println("OK");
} catch (Exception e) { e.printStackTrace(); }
finally {
if (con != null) try { con.close(); } catch(Exception e) {}
}
}}
When i try run this code i still getting error:
java.sql.sqlexception no suitable driver found for (..)
I have added path to sqljdbc4.jar to classpath variable and enu\auth\x64 localization to Path variable. I'm working on JRE 1.8, SQL Server 2014 and Windows 7.
It's because you haven't loaded the driver. Just modify your existing code
try {
//this will load the driver
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
con = DriverManager.getConnection(conUrl);
System.out.println("OK");
} catch (Exception e) { e.printStackTrace(); }
finally {
if (con != null) try { con.close(); } catch(Exception e) {}
}
Following is my Java code. In linux, it is working fine but in Windows I'm unable to insert data into the database on local disk. In NetBeans get it all right but .jar file not. JDBC driver see be good.
Connecting to database:
public static Connection connectToDb() {
try {
Connection connection = null;
DriverManager.registerDriver(new org.sqlite.JDBC());
//LINUX PATH
if (OSDetector.isLinux()) {
connection = DriverManager.getConnection("jdbc:sqlite:/home/" + userNameLinux + "/PDFMalwareDataAnalyser/DatabaseSQLite/database.db", NAME, PASSWORD);
//WINDOWS PATH
} else {
connection = DriverManager.getConnection("jdbc:sqlite:C:\\PDFMalwareDataAnalyser\\DatabaseSQLite\\database.db", NAME, PASSWORD);
}
connection.setAutoCommit(true);
if (connection != null) {
System.out.println("Otvorená.");
}
return connection;
} catch (SQLException e) {
System.err.println(e.getClass().getName() + e.getMessage());
// System.exit(0);
}
return null;
}
Insertion:
public void insertDataToDatabase(int idReport) throws SQLException {
connection = new SQLiteJDBC().connectToDb();
PreparedStatement insertCommunication = connection.prepareStatement("insert into table_communication values(?,?);");
insertCommunication.setString(2, communicationsFinal.toString());
try {
insertCommunication.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
}
insertCommunication.close();
connection.close();
System.out.println("1. --- Insert do tabuľky TABLE_COMMUNICATION OK ---");
}
Try this:
connection = DriverManager.getConnection("jdbc:sqlite:C:/PDFMalwareDataAnalyser/DatabaseSQLite/database.db")