CODEWITHSUNDEEP
javamysqljdbc
Reshad
Reshad

Reputation: 2652

Using database mysql in Java

I have started trying out some stuff so that I can use mysql database together with Java. First of all I have some questions about it.

I have used mysql a lot with PHP development but never with Java. Can I use the MySQL that MAMP brings or do I have to install it stand alone or something?

and second.. I have created this code with the help of a tutorial but the only output I get is

com.mysql.jdbc.Driver

The code that I have used for this you can find below:

package Databases;

import java.sql.*;

public class MysqlConnect{

/* These variable values are used to setup
the Connection object */

 static final String URL = "jdbc:mysql://localhost:3306/test";
 static final String USER = "root";
 static final String PASSWORD = "root";
 static final String DRIVER = "com.mysql.jdbc.Driver";

 public Connection getConnection() throws SQLException {
    Connection con = null;
    try {
       Class.forName(DRIVER); 
       con = DriverManager.getConnection(URL, USER, PASSWORD);
    }
    catch(ClassNotFoundException e) {
       System.out.println(e.getMessage());
       System.exit(-1);
    }
    return con;
 }

 public void getEmployees() {
    ResultSet rs = null;
    try {
       Statement s = getConnection().createStatement();
       rs = s.executeQuery("SELECT id, name, job_id, location FROM person");
       System.out.format("%3s %-15s %-7s %-7s%n", 
          "ID", "NAME", "JOB ID", 
            "LOCATION");
       System.out.format("%3s %15s %7s %7s%n", 
          "---", "---------------", 
            "-------", "--------");

       while(rs.next()) {
          long id = rs.getLong("id");
          String name = rs.getString("name");
          long job = rs.getLong("job_id");
          String location = rs.getString("location");
          System.out.format("%-3d %-15s %7d %5s%n", 
             id, name, job, location);
       }
    }
    catch(SQLException e) {
       System.out.println(e.getMessage());
       System.exit(-1);
    }
 }
}

Upvotes: 0

Views: 161

Answers (2)

BalusC
BalusC

Reputation: 1109695

It's coming from the following block:

catch(ClassNotFoundException e) {
   System.out.println(e.getMessage());
   System.exit(-1);
}

That's a pretty poor way of handling exceptions. You're just printing the exception message. You have no clue what's going on. Rather just throw it (which will end up with a nice stacktrace), or print a more descriptive message along alone the exception message, e.g.

catch(ClassNotFoundException e) {
   System.out.println("JDBC driver class not found in runtime classpath: " + e.getMessage());
   System.exit(-1);
}

How to fix the particular exception is in turn actually a second question (with a pretty obvious answer: just put JAR file containing JDBC driver class in runtime classpath), but ala, you may find this mini-tutorial helpful then: Connect Java to a MySQL database.

Unrelated to the concrete problem, I'm not sure which tutorial you're reading there, but I'd take it with a grain of salt. Apart from poor exception handling, it's also leaking DB resources in getEmployees() method by never closing the result set, statement and connection. This is absolutely not a good practice either. How to do it is also already covered in the aforelinked mini-tutorial. See further also: How often should Connection, Statement and ResultSet be closed in JDBC?

Upvotes: 7

Michael
Michael

Reputation: 2867

Yes, you need to install MySQL server locally or remotely.

The code will be usable if you also downloaded jdbc Driver jar from MySQL download pages. and you configured your MySQL instance with the proper username and password.

Upvotes: 0

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