Error: Could not find or load main class JDBCExample - java

Hello I am trying to run a java file in cmd (Windows) with this:
C:\test>java -cp c:\test\postgresql-9.3-1102.jdbc41.jar;c:\test JDBCExample
where postgresql-9.3-1102.jdbc41.jar & JDBCExample are already in the folder "test".
and JDBCExample.java is:
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.SQLException;
public class JDBCExample {
public static void main(String[] args) {
System.out.println("-------- PostgreSQL "
+ "JDBC Connection Testing ------------");
try {
Class.forName("org.postgresql.Driver");
} catch (ClassNotFoundException e) {
System.out.println("Where is your PostgreSQL JDBC Driver? "
+ "Include in your library path!");
e.printStackTrace();
return;
}
System.out.println("PostgreSQL JDBC Driver Registered!");
Connection connection = null;
try {
connection = DriverManager.getConnection(
"jdbc:postgresql://127.0.0.1:5432/testdb", "java_postgres",
"4scoreand7yearsago");
} catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
return;
}
if (connection != null) {
System.out.println("You made it, take control your database now!");
} else {
System.out.println("Failed to make connection!");
}
}
}
I have tried to run a simple "Hello World" java file in the same "test" folder yet it also says the same error.
And next, I also tried changing directory to a source folder of a .java file which I am REALLY SURE that it works perfect in Netbeans or Eclipse, (sorting algo and etc), yet still in the cmd it says the same error when compiling. :(
Any help? Also, I already added in the Path of my computer's Environment Variables a "C:\Program Files\Java\jdk1.7.0_45\bin;" and added a new one named CLASSPATH where it points to a "C:\Program Files\Java\jdk1.7.0_45\bin;C:\Program Files\Java\jre7\bin" but to no avail, still the same error.
OR COULD ANY OF YOU JUST HELP ME FIND ANOTHER WAY OF SETTING UP THE JDBC DRIVE. THAT'S ALL THANK YOU. T_T

My bad, it's only a matter of compilation and running problem.
/> javac JDBCExample.java
/> java JBDCExample
Sorry for the disturbance people! xD

Related

JDBC JAVA No suitable driver found for jdbc:mysql://localhost:3306/voting

Hello im trying to connect to a mysql database using JDBC my code is below.I get an error as such No suitable driver found.Searching around I found that the usual error is syntax or missing the jar file from the class path.I tried both of these solutions and dont know what to do next it wont connect.Also to manage the databases I have WAMP and mySQL workbench installed not sure if its related.
package test.jdbc;
import java.sql.*;
public class jdbctester {
public static void main(String[] args)
{
try
{
Connection myconn=DriverManager.getConnection("jdbc:mysql://localhost:3306/voting","root","Vanquish123");
Statement myStmt=myconn.createStatement();
ResultSet myRs=myStmt.executeQuery("select * from electoral");
/*
while(myRs.next())
{
System.out.println(myRs.getString("state")+","+myRs.getString("perDem"));
}
*/
}
catch(Exception exc)
{
exc.printStackTrace();
}
}
}
Try this:
Class.forName("fully qualified driver class name");
Java Class.forName, JDBC connection loading driver
this post states that you should not need it but it will not hurt you to try.
you have to add "com.mysql.jdbc_5.1.5.jar" in to your project build path... go to project property>build Path> library> add external jar and add jar file.
Connection conn = null;
try {
// Register JDBC driver
Class.forName(DRIVER).newInstance();
// Open a connection
conn = DriverManager.getConnection(Local_URL + , USERNAME, PASSWORD);
System.out.println("Connected Database Successfully...\n\n");
} catch (Exception se) {
throw new AppException("Failed to create Local Database connection", se);
}
return conn;

Connecting to MySQL using JDBC [duplicate]

This question already has answers here:
Connect Java to a MySQL database
(14 answers)
Closed 7 years ago.
I have searched the internet trying to find solutions on using java and JDBC to connect to MySQL. Unfortunately I have found multiple answers and none that solved my problem.
I downloaded the JDBC from MySQL, and unzipped the file to find the .jar. I placed the .jar in my C:/Program Files (X86)/Java/JDK.../JRE/lib/ext folder. I set my environmental variable classpath (maybe CLASSPATH, ClassPath ??) to the following:
%CLASSPATH%;.;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext
I use the script I composed based on all the different solutions I have seen to get this:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class MySql {
public static void main(String[] args)
{
Connection con = getConnection();
if (con != null) {
System.out.println("Connection Made");
}
else {
System.out.println("Connection not made");
}
}
private static Connection getConnection() {
Connection con = null;
try {
Class.forName("com.mysql.jdbc");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/sakila", "java", "java");
System.out.println("Connection Made");
conn.close();
}
catch (SQLException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
catch (ClassNotFoundException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
return con;
}
}
It compiles with javac MySql.java. Then when it runs (java MySql) I get com.mysql.jdbc. I have read that I don't need to register the driver, but when I remove Class.forName all I get is 'cannot find JDBC driver' error.
I can't narrow down my problem to either:
1). Classpath not setup correctly.
2). Improper java connection code.
3). Unable to locate MySQL server.
Any help would be appreciated.
Edit -
I placed the .jar file onto Desktop for testing purposes. Changed system classpath variable:
%CLASSPATH%;.;C:\User\User\Desktop\mysql-connector-java-5.1.38-bin.jar
Then when I add the trace for the error statement I get:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader.findClass<Unkown Source>
at java.lang.ClassLoader.loadclass (Unknown source)
at sun.misc.Launcher$AppClassLoader.loadclass(Unkown Source)
etc.
etc.
edit 2 - I have spent two days using Connect Java to a MySQL database as a resource and none of the instructions I have followed have solved my problem.
Instead of
System.out.println(e.getMessage());
Do this
e.printStackTrace();
You will see that the exception is:
java.lang.ClassNotFoundException: com.mysql.jdbc
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at MySql.getConnection(MySql.java:24)
at MySql.main(MySql.java:10)
Remove the Class.forName. You might get an access denied or some other error but it will solve the ClassNotFoundException. Here is the final edited version that should work:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class MySql {
public static void main(String[] args)
{
Connection con = getConnection();
if (con != null) {
System.out.println("Connection Made");
}
else {
System.out.println("Connection not made");
}
}
private static Connection getConnection() {
Connection con = null;
try {
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/sakila", "java", "java");
System.out.println("Connection Made");
conn.close();
}
catch (SQLException e)
{
e.printStackTrace();
System.exit(0);
}
return con;
}
}
If you need Class.forName() you have to use correct class:
Class.forName("com.mysql.jdbc.Driver");
But with JDBC 4 that has become no longer needed.
Create full Exception stack traces and use the result to search here - most common errors have been solved here before.
NoSuitableDriverFound is a very strong indication your mysql-connector.jar (not the .zip....) is missing from your classpath when you run your code.
You could try like this:
Run java -cp .;C:\User\User\Desktop\mysql-connector-java-5.1.38-bin.jar MySql
I think you must add the path including the jar file name of the driver in your classpath. Like so:
%CLASSPATH%;.;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\mysql-connector-java-xxx.jar
If your Java is version 6 or above you doesn't need Class.formName(...) code.
And for ensure that everything works, compile and execute your code in the follow way.
To compile:
java -cp PATH_TO_DRIVER; YOUR_CLASS.java
To execute:
java -cp PATH_TO_DRIVER; YOUR_CLASS
Change YOUR_CLASS to the name of your class and PATH_TO_DRIVER to the path where you download the MySQL driver.
Hope it helps!
Try this code!
public static void main(String[] argv) {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
System.out.println("Where is your MySQL JDBC Driver?");
e.printStackTrace();
return;
}
System.out.println("MySQL JDBC Driver Registered!");
Connection connection = null;
try {
connection = DriverManager
.getConnection("jdbc:mysql://localhost:3306/yourSCHEMAname,"login", "password");
} catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
return;
}
if (connection != null) {
System.out.println("You made it, take control your database now!");
} else {
System.out.println("Failed to make connection!");
}
}
}

Getting "The filename, directory name, or volume label syntax is incorrect" error while connecting to MySQL (wamp server) from JAVA (eclipse)

I have a basic JAVA-MySQL connection class. But, when I execute the code I get
The filename, directory name, or volume label syntax is incorrect
error.
I am using MySQL through wamp server. And, Eclipse is my IDE.
Code (MySQL_connection.java) :
import java.sql.*;
public class MySQL_connection {
public static void main(String args[]) {
try {
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost:8080/error_report","root","");
System.out.println("Connection success");
} catch (Exception e) {
System.err.println(e);
}
}
}
I have created error_report database from phpmyadmin.
Check to make sure your MySQL config file does not contain & in the XML. XML Files must use &amp

Connecting to MySQL Database from java in IDE Netbeans

So this is my thing. I am trying to connect do MySQL Database from java. I have downloaded connector driver from MySQL ( Its called "mysql-connector-java-5.0.8-bin.jar" ) and I added to my libraries (Im using NetBeans). I tried to do simple connection like this:
package datacon;
public class Datacon {
public static void main(String[] args) {
try {
java.sql.Connection con = (java.sql.Connection) java.sql.DriverManager
.getConnection("jdbc:mysql://localhost:3306/test"
/*, "root"
, "root" */ );
} catch ( Exception e ) {
System.out.println( e.toString() );
}
}
}
But this hapened:
java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/test
I made my research on the internet and this pretty common thing, but none of the answers helped me. I was able connect to database through NetBeans/services, so that URL jdbc:mysql://localhost:3306/test should be correct.
I am using:
java: Oracle java SDK 1.7.0 _ 45
IDE: NetBeans 7.4
OS: Debian 3.2.51-1 x86_64
Driver: MySQL Connector/J 5.0.8
I am afraid this is gonna have a very trivial answer, but I am stuck here for a while now and i need to move. So what am I missing?
Add:
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (final ClassNotFoundException e) {
e.printStackTrace();
}
}
I thing you forget to load driver .
Class.forName("com.mysql.jdbc.Driver");
and make sure you have mysql-connector-java-5.1.22-bin in your class path.
try {
Class.forName("org.gjt.mm.mysql.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","root");
} catch(ClassNotFoundException e) {
e.printStackTrace();
}
try {
class.forname("com.mysql.jdbc.Driver");
driver.getconnection("connenctionurl","name","password");
Statement s =goodrecive.asif().createStatement();
s.executeUpdate("INSERT INTO product(productno,productname,quantity,ammount)values('"+t1.getText()+"','"+t2.getText()+"','"+t3.getText()+"','"+t4.getText()+"')");
} catch (Exception e) {
System.out.println(e);
}
}
My class for connection:
package connection;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class ConnectionFactory {
public Connection getConnection() throws SQLException {
return DriverManager.getConnection("jdbc:mysql://localhost:3306/<database>", "<user>", "<password>");
}
}
Don't need add ClassForName. This is necessary in older versions of java.

no suitable driver found calling getConnection

I'm using MySQL 5.5 with its defaults. I created a user/password and ran a script creating a database called employees. Through the command prompt I can access the database:
mysql -u user -p
SELECT * FROM employees
In my Java application, I am unable to connect. I have tried these URLs, as well as others, but nothing works:
"jdbc:mysql://localhost/employees" "user" "password"
"jdbc:mysql://localhost:3306/employees" "user" "password"
"jdbc:mysql:///employees?user=user&password=password"
Here's the relevant code:
public Main()
{
try {
connection = DriverManager.getConnection(url);
//connection = DriverManager.getConnection(url, user, password);
// I don't know what else to try
} catch (SQLException ex) {
System.out.print(ex + "\n\n");
}
}
Make sure you have Mysql driver jar in the class path and check MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/connector-j-usagenotes-basic.html
The error tells me that either
ConnectorJ driver is not in your classpath.
OR
When using DriverManager, the jdbc.drivers system property has not been populated with the location of the Connector/J driver.
OR
The format of your connection URL is incorrect, or you are referencing the wrong JDBC driver.
In your scenario, it is the list item #1 which is the cause of the issue you are facing.
I would use something like below code snippet to get the connection object.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
Connection conn = null;
...
try {
conn =
DriverManager.getConnection("jdbc:mysql://localhost/employees?" +
"user=user&password=password");
// Do something with the Connection
...
} catch (SQLException ex) {
// handle any errors
System.out.println("SQLException: " + ex.getMessage());
System.out.println("SQLState: " + ex.getSQLState());
System.out.println("VendorError: " + ex.getErrorCode());
}

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