Not able to connect to MySQL using Java - java

I am using the below code to connect to MySQL
import java.sql.DriverManager;
import com.mysql.jdbc.Connection;
public class connectMysql {
public static void main(String[] args){
Connection conn = null;
try{
conn = (Connection)DriverManager.getConnection("jdbc:mysql://localhost:3306//test","root","admin");
if(conn!=null)
{
System.out.println("Connected successfully");
}
}catch(Exception e)
{
System.out.println("Not connected");
e.printStackTrace();
}
}
}
The username: root, password: admin, Hostname: localhost, Port: 3306.
I get the output as "Not connected".
[Edits] Now I Stack Trace and see that error is 'Unknown database '/test'. But I do have a schema named test. Is the schema same as the database?
Everything is same as this. But I don't seem to get connected to the DB.
Thanks for the help!!!

Why you have double slash // before your database name in your connection string
jdbc:mysql://localhost:3306//test","root","admin"
Change it to
jdbc:mysql://localhost:3306/test","root","admin"

Check all the drivers are available in the Library
Check for the port number, Username and password(case Sensitive)
if every thing is correct then
use the below code
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "username", "password");
statement = con.createStatement();

Related

Cannot access H2 server from remote machine

I have a new H2 test DB all setup and have no issue getting to it locally.
I used this site to help https://www.tutorialspoint.com/h2_database/h2_database_jdbc_connection.htm
I took the code and put it up on an Amazon web server and can confirm it is indeed running and can, again, locally add data to it and access it VIA code and the H2 console. The H2 console can even be reached from my remote PC.
Now on my PC I am trying to get to the server VIA JDBC but cannot. Server is even set up for the TCP server.
in the properties file
spring.datasource.url=jdbc.h2.mem.test
In the application.java file, in a try-catch, and it reports the server did start.
Server.createTcp.Server().start();
The DB has a table called testable in there with server columns and test rows. And Again locally and even in the H2 console, I can get to the data no problem.
I tried several ways to list the URL in Java code to get to the server VIA JDBC.
here is the fake URL that I can get to a website hosted there just fine as well as the H2 console.
https://www.mywebsitehostedonamazon.com/h2
I have added this to my code to the connection for the URL.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class H2jdbcCreateDemo {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "org.h2.Driver";
static final String DB_URL = "jdbc:h2:tcp://https://www.mywebsitehostedonamazon.com:8082/test";
// Database credentials
static final String USER = "sa";
static final String PASS = "password";
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
// STEP 1: Register JDBC driver
Class.forName(JDBC_DRIVER);
//STEP 2: Open a connection
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
//STEP 3: Execute a query
System.out.println("Creating table in given database...");
stmt = conn.createStatement();
String sql = "SELECT * FROM testable LIMIT 1";
stmt.executeUpdate(sql);
System.out.println("Created table in given database...");
// STEP 4: Clean-up environment
stmt.close();
conn.close();
} catch(SQLException se) {
//Handle errors for JDBC
se.printStackTrace();
} catch(Exception e) {
//Handle errors for Class.forName
e.printStackTrace();
} finally {
//finally block used to close resources
try{
if(stmt!=null) stmt.close();
} catch(SQLException se2) {
} // nothing we can do
try {
if(conn!=null) conn.close();
} catch(SQLException se){
se.printStackTrace();
} //end finally try
} //end try
System.out.println("Goodbye!");
}
}
When I run this I receive a Zero length string error for line conn = DriverManager.getConnection(DB_URL,USER,PASS);
If I change up the URL then I get a connection time out. jdbc:h2:tcp://www.mywebsitehostedonamazon.com:8082/test
If I change up the URL then I get a connection time out. jdbc:h2:tcp://www.mywebsitehostedonamazon.com:8082/mem:test
If I change up the URL then I get an error that the Table "testable" not found. jdbc:h2:mem://www.mywebsitehostedonamazon.com:8082/mem:test
Can anyone help out with this?

Connect to SQL server from Java

I'm trying to connect from SSMS(SQL Server Management Studio) to Eclipse(Java), but I keep getting this error message:
com.microsoft.sqlserver.jdbc.SQLServerException: The connection to the host localhost, named instance sqlexpress failed. Error: "java.net.SocketTimeoutException: Receive timed out". Verify the server and instance names and check that no firewall is blocking UDP traffic to port 1434. For SQL Server 2005 or later, verify that the SQL Server Browser Service is running on the host.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:234)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.getInstancePort(SQLServerConnection.java:6132)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.primaryPermissionCheck(SQLServerConnection.java:2609)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:2346)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectInternal(SQLServerConnection.java:2213)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:1276)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:861)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
at net.codejava.sql.JavaConnect2SQL.main(JavaConnect2SQL.java:16)
The code I do have is:
import java.sql.DriverManager;
import java.sql.SQLException;
//import com.sun.jdi.connect.spi.Connection;
public class JavaConnect2SQL {
public static void main(String[] args) {
// TODO Auto-generated method stub
String url = "jdbc:sqlserver://localhost\\SQLEXPRESS;databaseName=students"; // This is where I think the error is
String user = "sa";
String password = "123";
try {
java.sql.Connection connection = DriverManager.getConnection(url, user, password);
System.out.println("Succesfully connected to Microsoft SQL Server");
}catch (SQLException e) {
System.out.println("Oops! There was an error: ");
e.printStackTrace();
}
}
}
I think the problem is in the connection URL, but I don't know the host name/instance name. If you can tell me how to get my host name/instance name, that would be appreciated. But if the problem is something else, please tell me!
Edit: I have changed the code, and I'm now getting a different. Here is the new code:
package net.codejava.sql;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JavaConnect2SQL {
public static void main(String[] args) {
// Create a variable for the connection string.
String url = " jdbc:sqlserver://LAPTOP-5697KK36:1433;databaseName=students";
String user= "sa";
String password = "123";
try {
Connection connection = DriverManager.getConnection(url, user, password);
System.out.println("Connection succesful!");
}
// Handle any errors that may have occurred.
catch (SQLException e) {
System.out.println("Here is your error message: ");
e.printStackTrace();
}
}
}
The new error message is this:
java.sql.SQLException: No suitable driver found for jdbc:sqlserver://LAPTOP-5697KK36:1433;databaseName=students
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:702)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
at net.codejava.sql.JavaConnect2SQL.main(JavaConnect2SQL.java:40)
I think the problem is that I installed the wrong version of JDBC Driver. My JRE version is 12.0.1. What is the correct JDBC Driver to install.
You can check in SQL server configuration manager and Microsoft SQL server management studio. The state must be running in server configuration manager and you can try to connect your database in Microsoft SQL server management with your password.
if you connect successfully then there is another problem but it looks like the database is stopped.

using a Java DB Connection in another form

I have created a simple Java connection script in Java to connect to a database shown below.
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class dbconn {
public static void main(String[] args) throws ClassNotFoundException
{
Class.forName("org.sqlite.JDBC");
Connection connection = null;
try
{
// create a database connection
connection = DriverManager.getConnection("jdbc:sqlite:C:/Program Files (x86)/Spiceworks/db/spiceworks_prod.db");
Statement statement = connection.createStatement();
statement.setQueryTimeout(30); // set timeout to 30 sec.
}
catch(SQLException e)
{
// if the error message is "out of memory",
// it probably means no database file is found
System.err.println(e.getMessage());
}
finally
{
try
{
if(connection != null)
connection.close();
}
catch(SQLException e)
{
// connection close failed.
System.err.println(e);
}
}
}
}
Now I have tested this connection via some SQL queries inside the dbconn script and it works.
However my question is, how would Icall this instance of the database into another form in the same project to preform the same SQL queries which are:
ResultSet resultSet = null;
resultSet = statement.executeQuery("SELECT * FROM users");
while (resultSet.next())
{
System.out.println("EMPLOYEE Email: " + resultSet.getString("email"));
}
You can retain and reuse the Connection, saving it probably in some static field. If you access it from multiple threads, SQLite must work in the Serialized mode. You must have the code somewhere to re-establish the connection if it has been lost for some reason.
If the use of Connection is not heavy, you can also have some method that opens it and close when no longer needed, better inside the finally block.

Cannot connect jdbc to sql server

Below is my code for a simple select query for the Sql Server using jdbc.
import java.sql.*;
import java.util.*;
public class DateServer{
public void dbconnect(String conn, String user, String pass){
try{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con = DriverManager.getConnection(conn, user, pass);
System.out.println("connected");
Statement stat = con.createStatement();
String query = "select * from headcount_new";
ResultSet rs = stat.executeQuery(query);
}
catch (Exception e){
e.printStackTrace();
}
}
public static void main(String[] args){
DateServer conserver = new DateServer();
conserver.dbconnect("jdbc:sqlserver://<<hostname>&gt", "<<username>&gt", "<<password>&gt");
}
}
I am getting the following error:
com.microsoft.sqlserver.jdbc.SQLServerException: The connection string contains a badly formed name or value.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:171)
at com.microsoft.sqlserver.jdbc.Util.parseUrl(Util.java:420)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.parseAndMergeProperties(SQLServerDriver.java:856)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:838)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:221)
at DateServer.dbconnect(DateServer.java:9)
at DateServer.main(DateServer.java:22)"
Can someone please help me what the error is about? I am new to Java.
thanks.
Not sure why you have <<hostname>&gt etc
A JDBC URL looks like this
jdbc:sqlserver://SomeServer;user=SomeUser;password=XXX;
this has nothing to do with java. in your connection string you have to replace '<hostname>', '<username>', etc. with actual values. See here for valid syntax: http://www.java2s.com/Tutorial/Java/0340__Database/AListofJDBCDriversconnectionstringdrivername.htm

How do I connect to a SQL Server 2008 database using JDBC?

I have MSSQL 2008 installed on my local PC, and my Java application needs to connect to a MSSQL database. I am a new to MSSQL and I would like get some help on creating user login for my Java application and getting connection via JDBC. So far I tried to create a user login for my app and used following connection string, but I doesn't work at all. Any help and hint will be appreciated.
jdbc:jtds:sqlserver://127.0.0.1:1433/dotcms
username="shuxer" password="itarator"
There are mainly two ways to use JDBC - using Windows authentication and SQL authentication. SQL authentication is probably the easiest. What you can do is something like:
String userName = "username";
String password = "password";
String url = "jdbc:sqlserver://MYPC\\SQLEXPRESS;databaseName=MYDB";
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection conn = DriverManager.getConnection(url, userName, password);
after adding sqljdbc4.jar to the build path.
For Window authentication you can do something like:
String url = "jdbc:sqlserver://MYPC\\SQLEXPRESS;databaseName=MYDB;integratedSecurity=true";
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection conn = DriverManager.getConnection(url);
and then add the path to sqljdbc_auth.dll as a VM argument (still need sqljdbc4.jar in the build path).
Please take a look here for a short step-by-step guide showing how to connect to SQL Server from Java using jTDS and JDBC should you need more details. Hope it helps!
You can use this :
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class ConnectMSSQLServer
{
public void dbConnect(String db_connect_string,
String db_userid,
String db_password)
{
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection conn = DriverManager.getConnection(db_connect_string,
db_userid, db_password);
System.out.println("connected");
Statement statement = conn.createStatement();
String queryString = "select * from sysobjects where type='u'";
ResultSet rs = statement.executeQuery(queryString);
while (rs.next()) {
System.out.println(rs.getString(1));
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args)
{
ConnectMSSQLServer connServer = new ConnectMSSQLServer();
connServer.dbConnect("jdbc:sqlserver://<hostname>", "<user>",
"<password>");
}
}
I am also using mssql server 2008 and jtds.In my case I am using the following connect string and it works.
Class.forName( "net.sourceforge.jtds.jdbc.Driver" );
Connection con = DriverManager.getConnection( "jdbc:jtds:sqlserver://<your server ip
address>:1433/zacmpf", userName, password );
Statement stmt = con.createStatement();
If your having trouble connecting, most likely the problem is that you haven't yet enabled the TCP/IP listener on port 1433. A quick "netstat -an" command will tell you if its listening. By default, SQL server doesn't enable this after installation.
Also, you need to set a password on the "sa" account and also ENABLE the "sa" account (if you plan to use that account to connect with).
Obviously, this also means you need to enable "mixed mode authentication" on your MSSQL node.
Try to use like this: jdbc:jtds:sqlserver://127.0.0.1/dotcms; instance=instanceName
I don't know which version of mssql you are using, if it is express edition, default instance is sqlexpress
Do not forget check if SQL Server Browser service is running.
You can try configure SQL server:
Step 1: Open SQL server 20xx Configuration Manager
Step 2: Click Protocols for SQL.. in SQL server configuration. Then, right click TCP/IP, choose Properties
Step 3: Click tab IP Address, Edit All TCP. Port is 1433
NOTE: ALL TCP port is 1433
Finally, restart the server.
Simple Java Program which connects to the SQL Server.
NOTE: You need to add sqljdbc.jar into the build path
// localhost : local computer acts as a server
// 1433 : SQL default port number
// username : sa
// password: use password, which is used at the time of installing SQL server management studio, In my case, it is 'root'
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class Conn {
public static void main(String[] args) throws InstantiationException, IllegalAccessException, ClassNotFoundException {
Connection conn=null;
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver").newInstance();
conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=company", "sa", "root");
if(conn!=null)
System.out.println("Database Successfully connected");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
Try this.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class SQLUtil {
public void dbConnect(String db_connect_string,String db_userid,
String db_password) {
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection conn = DriverManager.getConnection(db_connect_string,
db_userid, db_password);
System.out.println("connected");
Statement statement = conn.createStatement();
String queryString = "select * from cpl";
ResultSet rs = statement.executeQuery(queryString);
while (rs.next()) {
System.out.println(rs.getString(1));
}
} catch (Exception e) {
e.printStackTrace();
} }
public static void main(String[] args) {
SQLUtil connServer = new SQLUtil();
connServer.dbConnect("jdbc:sqlserver://192.168.10.97:1433;databaseName=myDB",
"sa",
"0123");
}
}
Try this
Class.forName( "net.sourceforge.jtds.jdbc.Driver" );
String url ="Jdbc:jtds:sqlsever://ip/instanceName;instance=instanceName;databseName=dbName;user=yourUser;password=yourpass;";

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