JDBC - Batching with Statement Object
Here is a typical sequence of steps to use Batch Processing with Statement Object −
Create a Statement object using either createStatement() methods.
Set auto-commit to false using setAutoCommit().
Add as many as SQL statements you like into batch using addBatch() method on created statement object.
Execute all the SQL statements using executeBatch() method on created statement object.
Finally, commit all the changes using commit() method.
This sample code has been written based on the environment and database setup done in the previous chapters.
Copy and past the following example in JDBCExample.java, compile and run as follows −
// Import required packages import java.sql.*; public class JDBCExample { // 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{ // Register JDBC driver Class.forName("com.mysql.jdbc.Driver"); // Open a connection System.out.println("Connecting to database..."); conn = DriverManager.getConnection(DB_URL,USER,PASS); // Create statement System.out.println("Creating statement..."); stmt = conn.createStatement(); // Set auto-commit to false conn.setAutoCommit(false); // First, let us select all the records and display them. printRows( stmt ); // Create SQL statement String SQL = "INSERT INTO Employees (id, first, last, age) " + "VALUES(200,'Zia', 'Ali', 30)"; // Add above SQL statement in the batch. stmt.addBatch(SQL); // Create one more SQL statement SQL = "INSERT INTO Employees (id, first, last, age) " + "VALUES(201,'Raj', 'Kumar', 35)"; // Add above SQL statement in the batch. stmt.addBatch(SQL); // Create one more SQL statement SQL = "UPDATE Employees SET age = 35 " + "WHERE id = 100"; // Add above SQL statement in the batch. stmt.addBatch(SQL); // Create an int[] to hold returned values int[] count = stmt.executeBatch(); //Explicitly commit statements to apply changes conn.commit(); // Again, let us select all the records and display them. printRows( stmt ); // Clean-up environment 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 public static void printRows(Statement stmt) throws SQLException{ System.out.println("Displaying available rows..."); // Let us select all the records and display them. String sql = "SELECT id, first, last, age FROM Employees"; ResultSet rs = stmt.executeQuery(sql); 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); } System.out.println(); rs.close(); }//end printRows() }//end JDBCExample
Now let us compile the above example as follows −
C:\>javac JDBCExample.java C:\>
When you run JDBCExample, it produces the following result −
C:\>java JDBCExample Connecting to database... Creating statement... Displaying available rows... ID: 95, Age: 20, First: Sima, Last: Chug ID: 100, Age: 18, First: Zara, Last: Ali ID: 101, Age: 25, First: Mahnaz, Last: Fatma ID: 102, Age: 30, First: Zaid, Last: Khan ID: 103, Age: 30, First: Sumit, Last: Mittal ID: 110, Age: 20, First: Sima, Last: Chug Displaying available rows... ID: 95, Age: 20, First: Sima, Last: Chug ID: 100, Age: 35, First: Zara, Last: Ali ID: 101, Age: 25, First: Mahnaz, Last: Fatma ID: 102, Age: 30, First: Zaid, Last: Khan ID: 103, Age: 30, First: Sumit, Last: Mittal ID: 110, Age: 20, First: Sima, Last: Chug ID: 200, Age: 30, First: Zia, Last: Ali ID: 201, Age: 35, First: Raj, Last: Kumar Goodbye! C:\>