Connect to MySQL in Java
It’s been too long, I didnt get time to post anything OpenSource.
So here I am again with one simple class Database, to connect to MySQL in Java.
You can use this class in 2 ways –
- Specifying user,pwd and database name to connect
- Specifying connection ID and class will load rest of the variables from CONFIG file
Here I will post the Database class only, class to read config file and loading properties will be posted in different post.
The Database
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import java.sql.*; public class Database { Connection conn; Statement stmt; PreparedStatement pstmt; ResultSet rs; Config cfg; int affectedRows; /*Reading From CFG*/ String dbuser,dbpwd,dbname,dbserver; public Database(){ } public Database(String database, String user,String pwd) { this.affectedRows = 0; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/"+database, user , pwd); stmt = conn.createStatement(); } catch (Exception e){ e.printStackTrace(); } } public Database(String dbid) { cfg = new Config(); this.dbname = cfg.getProperty("mStrName"+dbid); this.dbuser = cfg.getProperty("mStrUser"+dbid); this.dbpwd = cfg.getProperty("mStrPwds"+dbid); this.dbserver = cfg.getProperty("mStrHost"+dbid); try { Class.forName("com.mysql.jdbc.Driver").newInstance(); conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/"+this.dbname, this.dbuser , this.dbpwd); stmt = conn.createStatement(); } catch (Exception e){ e.printStackTrace(); } } public ResultSet query(String qry) { try{ rs = this.stmt.executeQuery(qry); }catch(SQLException se){ System.out.println("Error : " + se.getMessage()); } return rs; } public int update(String qry) { int count = 0; try{ count = this.stmt.executeUpdate(qry); }catch(Exception se){ System.out.println("Error : " + se.getMessage()); } return count; } } |
And here is how we are going to use this class:
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Database db = new Database("mydb","myuser","mypwd"); //simple query ResultSet rs = db.query("SELECT * FROM mytable"); |
Now you can traverse record rs set in a way you want…
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//update query int affected = db.update("DELETE FROM mytable"); |
We will shortly see how we are going to use Config class and its usage.
Summary
So now yo have seen how its easy to connect to MySQL in Java. I hope you find this example useful and you can use in any of your assignment or project.
