This question already has an answer here:
What is JDBC counterpart of Postgres' "\connect" command?
(1 answer)
Closed 5 years ago.
This code connects abd create a database ,how can I select the created database to use it?
public class Connect {
public static void main(String[] args) {
Connection connection = null;
try {
Class.forName("org.postgresql.Driver");
connection = DriverManager.getConnection(
"jdbc:postgresql://localhost:5432/","postgres", "12345");
Statement statement = connection.createStatement();
statement.execute("CREATE DATABASE mydb");
//now I hav to connect to mydb
connection.close();
} catch (ClassNotFoundException ex) {
Logger.getLogger(OracleToPostgres.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(OracleToPostgres.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Something like this will do ...
Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/mydb", "user", "password");
Related
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
The infamous java.sql.SQLException: No suitable driver found
(21 answers)
Closed 11 days ago.
Unable to connect Postgres database to Tomcat 10.0.27 server
Here is DBConnection code:
public class DBConnection {
public static Connection getConnectionToDatabase() {
Connection connection = null;
try {
System.out.println("MySQL JDBC Driver Registered!");
connection = DriverManager.getConnection("jdbc:postgresql://localhost:5432/hplus", "postgres", "");
}
catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
}
if (connection != null) {
System.out.println("Connection made to DB!");
}
return connection;
}
}
Here is the code, where i try to get the connection:
public class ApplicationDao {
public List<Product> searchProducts(String searchString) {
Product product = null;
List<Product> products = new ArrayList<>();
try{
Connection connection = DBConnection.getConnectionToDatabase();
String sql = "select * from products where product_name like '%"+searchString+"%'";
Statement statement = connection.createStatement();
ResultSet set = statement.executeQuery(sql);
while(set.next()){
product= new Product();
product.setProductId(set.getInt("product_id"));
product.setProductImgPath(set.getString("image_path"));
product.setProductName(set.getString("product_name"));
products.add(product);
}
}
catch(SQLException exception){
exception.printStackTrace();
}
return products;
}
}
Here is what i get:
HTTP Status 500 – Internal Server Error
Type Exception Report
Message Cannot invoke "java.sql.Connection.createStatement()" because "connection" is null
I tried to debug the code but got no response. I looked on different forms what the problem is, but I did not find anything
The problem was in incorrect driver. Everything work out after adding this lines of code in DBConnection class:
try {
Class.forName("org.postgresql.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
// ...
This question already has answers here:
Connect Java to a MySQL database
(14 answers)
Closed 1 year ago.
how to connect mysql database from server on netbeans
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/pmsdb", "root", "");
return con;
} catch(Exception e) {
System.out.println(e);
return null;
}
There is a standard idiom to create a JDBC connection ...
You can debug you configuration by just using this class and clicking the "Run" button in your IDE.
If it does not work for you add the error output to the original question and we can debug further.
public class JdbcConnection {
public static void main(String a[]){
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con = DriverManager.
getConnection("jdbc:oracle:thin:#<hostname>:<port num>:<DB name>"
,"user","password");
Statement stmt = con.createStatement();
System.out.println("Created DB Connection....");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
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 want to insert data from a table which connection is oracle to another table which connection is mysql. I use netbeans and jdbc driver.
Is it possible? I mean how can I do select data from A table (X connection) and insert B table (Y connection)
connection X = DriverManager.getConnection("jdbc:oracle:thin:#" + host__ + ":" + port__ + servic, props);
connection Y = DriverManager.getConnection("jdbc:mysql://hostname:port/dbname","username", "password");
conn.close();
Thank you.
Here is a small example that copies a database table to another database.
You just need two connections conf(rom) and cont(o). You will need to modify both getConnection parameters, table names and field types.
// Copy
Statement stf, stmt;
Connection conf, cont;
ResultSet rsf, rs;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
Class.forName("com.mysql.jdbc.Driver");
conf = DriverManager.getConnection("jdbc:oracle:thin:#localhost:1521:" + databaseFrom, "user1", "passwd1");
try {
stf = conf.createStatement();
rsf = stf.executeQuery("select * from supplier order by sname");
// read from rsf write to rs!
cont = DriverManager.getConnection("jdbc:mysql://localhost:3306/" + databaseTo, "user2", "passwd2");
stmt = cont.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
rs = stmt.executeQuery("select * from supplier order by sname");
while (rsf.next()) {
rs.moveToInsertRow();
rs.updateInt(1, rsf.getInt(1));
rs.updateString(2, rsf.getString(2));
rs.updateString(3, rsf.getString(3));
rs.updateString(4, rsf.getString(4));
rs.updateInt(5, rsf.getInt(5));
rs.updateString(6, rsf.getString(6));
rs.updateInt(7, rsf.getInt(7));
rs.updateDouble(8, rsf.getDouble(8));
rs.updateString(9, rsf.getString(9));
rs.insertRow();
}
} catch (SQLException s) {
JOptionPane.showMessageDialog(this, "problem creating database " + s);
}
} catch (Exception e) {
JOptionPane.showMessageDialog(this, e.getStackTrace());
} finally {
if (stf != null) {
try {
stf.close();
stmt.close();
} catch (SQLException e) {
// handle Exception
}
}
if (conf != null) {
try {
conf.close();
cont.close();
} catch (SQLException e) {
// handle Exception
}
}
}
You can create two classes for different connection:
public class OracleConnectionManager {
public static Connection getOracleConnection() throws SQLException, ClassNotFoundException {
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection connection = null;
connection = DriverManager.getConnection(
"jdbc:oracle:thin:#localhost:1521:oracle","username","password");
return connection;
}
}
public class MySqlConnectionManager {
public static Connection getMySqlConnection() throws SQLException, ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = null;
connection = DriverManager.getConnection(
"jdbc:mysql://localhost:3306:mysql","username","password");
return connection;
}
}
Now you can use these classes to get the specific connections and do whatever you want.
You can get the oracle database connection and get the oracle statement > Resultsset, iterate over it
and insert the data into mysql.
Please let me know in case more information is required.
Follow these steps:
Connect to the Oracle database with one data access class
Connect to the MySQL database with a different data access class
Read row(s) from a table in the Oracle database
Perform any column transformations
Write row(s) to a table in the MySQL database
Close the database connections
I am trying to connect a database named DailyRoutine. My SQL file stored in the same file as Java source files. Here is my code section:
String url = "jdbc:mysql://DailyRoutine";
try {
Connection con = DriverManager.getConnection(url);
} catch (SQLException ex) {
Logger.getLogger(JavaApplication2.class.getName())
.log(Level.SEVERE, null, ex);
}
What is the problem here? Where should I store SQL file?
Have you loaded the JDBC driver?
String url = "jdbc:mysql://DailyRoutine";
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url);
} catch (SQLException ex) {
Logger.getLogger(JavaApplication2.class.getName()).log(Level.SEVERE, null, ex);
}