Created
October 28, 2019 12:47
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FirstExample (JDBC)
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//STEP 1. Import required packages | |
import java.sql.*; | |
public class FirstExample { | |
// JDBC driver name and database URL | |
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; | |
static final String DB_URL = "jdbc:mysql://localhost/EMP"; | |
// Database credentials | |
static final String USER = "username"; | |
static final String PASS = "password"; | |
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 id, first, last, age FROM Employees"; | |
ResultSet rs = stmt.executeQuery(sql); | |
//STEP 5: Extract data from result set | |
while(rs.next()){ | |
//Retrieve by column name | |
int id = rs.getInt("id"); | |
int age = rs.getInt("age"); | |
String first = rs.getString("first"); | |
String last = rs.getString("last"); | |
//Display values | |
System.out.print("ID: " + id); | |
System.out.print(", Age: " + age); | |
System.out.print(", First: " + first); | |
System.out.println(", Last: " + last); | |
} | |
//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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