неділя, 18 січня 2015 р.

How to extract data from the Data Table

1. Suppose we have database: (how to create table you can see here)



2. add driver (Project>Properties>Java Build Path>Libraries>Add External JARs... in the window take mysql-connector-java-5.0.8-bin)
Driver can be downloaded from here

3. add code
package DB;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestDataTable {

// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/rusyn";

//  Database credentials
static final String USER = "root";
static final String PASS = "1234";

public static void main(String[] args) {

Connection conn = null;
  Statement stmt = null;
  try{
     //STEP 2: Register JDBC driver
     Class.forName("com.mysql.jdbc.Driver");

     //STEP 3: Open a connection
     System.out.println("Connecting to database...");
     conn = DriverManager.getConnection(DB_URL,USER,PASS);

     //STEP 4: Execute a query
     System.out.println("Creating statement...");
     stmt = conn.createStatement();
     String sql;
     sql = "SELECT userID, FirstName FROM users";
     ResultSet rs = stmt.executeQuery(sql);

     //STEP 5: Extract data from result set
     while(rs.next()){
        //Retrieve by column name
        int id  = rs.getInt("userID");
        String name = rs.getString("FirstName");

        //Display values
        System.out.print("ID: " + id);
        System.out.print(", Name: " + name);

     }
     //STEP 6: Clean-up environment
     rs.close();
     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!");
}//end main
}//end FirstExample


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